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JM
04-30-07, 11:42 AM
A customer of mine (I'm an IT-for-hire person) has Comcast business class
cable internet service. A few weeks ago they started experiencing
intermittent internet. They have a Comcast/Netgear combo device
(router/modem/firewall) that we have configured for what they call "router
mode," which I call "bridge mode." Either way, we have a static IP address
that is passed through to our LAN, NAT and firewall in the device turned
off. I have the IP address configured on one of the NICs in a Novell
server. The second NIC in the server is for the LAN, with the server giving
out DHCP. There have been no problems there. The Novell server also is our
main app server and our email (Groupwise) server. When the internet is
down, everything else works fine. And I changed out the WAN NIC twice.
Point being there are no indications that the server is behaving in a way
that would cause the internet problems.

Each morning when they show up for work the internet is down. They call me,
and I start trying to ping both the IP of the Netgear (gateway address) and
the server (static IP). Usually, I cannot get a response from either
address. Occasionally I can get a response from the gateway, but not the
server (and of course I can never get the server and not the gateway). This
weekend I performed random ping tests to the gateway, and I caught it down
at least 5 times.

Comcast has changed out the Netgear unit 2 times (meaning we've had 3 of the
units). They monitored the device for several days and say it does not go
"off-line." However, this morning they told me that, yet neither I nor the
support rep could ping the gateway. She offered to "reset the modem" for
me. As soon as she did, I could ping the gateway, the server, and the
internet was up at the office.

Comcast's theory - after many, many support calls, as well as changing out
the box twice - is that something on the client's network side is "locking
up" their device (the Netgear).

Does that make any sense?


jm

Warren H
04-30-07, 02:08 PM
JM wrote:
>A customer of mine (I'm an IT-for-hire person) has Comcast business
>class cable internet service. A few weeks ago they started
>experiencing intermittent internet. They have a Comcast/Netgear combo
>device (router/modem/firewall) that we have configured for what they
>call "router mode," which I call "bridge mode." Either way, we have a
>static IP address that is passed through to our LAN, NAT and firewall
>in the device turned off. I have the IP address configured on one of
>the NICs in a Novell server. The second NIC in the server is for the
>LAN, with the server giving out DHCP. There have been no problems
>there. The Novell server also is our main app server and our email
>(Groupwise) server. When the internet is down, everything else works
>fine. And I changed out the WAN NIC twice. Point being there are no
>indications that the server is behaving in a way that would cause the
>internet problems.
>
> Each morning when they show up for work the internet is down. They
> call me, and I start trying to ping both the IP of the Netgear
> (gateway address) and the server (static IP). Usually, I cannot get a
> response from either address. Occasionally I can get a response from
> the gateway, but not the server (and of course I can never get the
> server and not the gateway). This weekend I performed random ping
> tests to the gateway, and I caught it down at least 5 times.
>
> Comcast has changed out the Netgear unit 2 times (meaning we've had 3
> of the units). They monitored the device for several days and say it
> does not go "off-line." However, this morning they told me that, yet
> neither I nor the support rep could ping the gateway. She offered to
> "reset the modem" for me. As soon as she did, I could ping the
> gateway, the server, and the internet was up at the office.
>
> Comcast's theory - after many, many support calls, as well as changing
> out the box twice - is that something on the client's network side is
> "locking up" their device (the Netgear).
>
> Does that make any sense?


You start by saying that there are intermittent outages, but you only
specifically mention it being down first thing in the morning. Are there
on-going problems at random times during the day, or is this only
happening when the connection has been idle for some time?

If the problem appears often after the use of the Internet connection
has been unused for a period of time, then I would check to see if the
server is shutting down the NIC because of some power management
setting.

Also, if it only happens overnight, set it up to run ping continuously
overnight, and see if the problem goes away.

Something else you could try is instead of having the Novell server
connected to the Internet, connect a different system. Of course this
wouldn't be practical during the work day, so you'd probably have to do
this over the weekend. Make sure there are no power management settings
to shut parts of that system down when idle, and test to see if the
Internet connection goes down.

BTW... You don't mention how you get the connection back up when it goes
down. Are you rebooting the server? Power-cycling the modem? Calling
Comcast, and having them reset the modem remotely? What does, and what
doesn't work to bring the connection back up?

--
Warren H.

==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.

Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker

JM
04-30-07, 04:28 PM
>>A customer of mine (I'm an IT-for-hire person) has Comcast business class
>>cable internet service. A few weeks ago they started experiencing
>>intermittent internet. They have a Comcast/Netgear combo device
>>(router/modem/firewall) that we have configured for what they call "router
>>mode," which I call "bridge mode." Either way, we have a static IP
>>address that is passed through to our LAN, NAT and firewall in the device
>>turned off. I have the IP address configured on one of the NICs in a
>>Novell server. The second NIC in the server is for the LAN, with the
>>server giving out DHCP. There have been no problems there. The Novell
>>server also is our main app server and our email (Groupwise) server. When
>>the internet is down, everything else works fine. And I changed out the
>>WAN NIC twice. Point being there are no indications that the server is
>>behaving in a way that would cause the internet problems.
>>
>> Each morning when they show up for work the internet is down. They call
>> me, and I start trying to ping both the IP of the Netgear (gateway
>> address) and the server (static IP). Usually, I cannot get a response
>> from either address. Occasionally I can get a response from the gateway,
>> but not the server (and of course I can never get the server and not the
>> gateway). This weekend I performed random ping tests to the gateway, and
>> I caught it down at least 5 times.
>>
>> Comcast has changed out the Netgear unit 2 times (meaning we've had 3 of
>> the units). They monitored the device for several days and say it does
>> not go "off-line." However, this morning they told me that, yet neither
>> I nor the support rep could ping the gateway. She offered to "reset the
>> modem" for me. As soon as she did, I could ping the gateway, the server,
>> and the internet was up at the office.
>>
>> Comcast's theory - after many, many support calls, as well as changing
>> out the box twice - is that something on the client's network side is
>> "locking up" their device (the Netgear).
>>
>> Does that make any sense?

Thank you very much for your excellent reply.
Here are some answers (I'll get other answers this evening).

> You start by saying that there are intermittent outages, but you only
> specifically mention it being down first thing in the morning. Are there
> on-going problems at random times during the day, or is this only
> happening when the connection has been idle for some time?

It happens throughout the day, mostly on the server's static address (for
terminology clarification, I'll use "gateway" address and "server" address
from now on). This fact led Comcast to conclude pretty early on that the
problem was on our side, since when we called during the day they could ping
the gateway address. That was reasonable, enough, until I started finding
the gateway address down at certain times, too, and often it's down in the
morning. However, over the weekend, I had failed ping tests to the gateway
at various times, day and night. Another fact perhaps worth mentioning is
that every workstation in the business is turned off at night and weekends.
So whatever is happening along the lines of Comcast's theory is limited
solely to server activity. In other words, if some activity on the lan side
indeed is "locking up" the Netgear, it's emanating from the server, not a
workstation, i.e., a malware-infected computer flooding the network. (and
I'm being open-minded, but I have my doubts in any event that something
lan-side could indeed lock up a cable modem). In general, there seems to be
no relationship to idle time.



> If the problem appears often after the use of the Internet connection has
> been unused for a period of time, then I would check to see if the server
> is shutting down the NIC because of some power management setting.

This does not appear to be the case.


> Also, if it only happens overnight, set it up to run ping continuously
> overnight, and see if the problem goes away.

As mentioned, it happens day and night.


> Something else you could try is instead of having the Novell server
> connected to the Internet, connect a different system. Of course this
> wouldn't be practical during the work day, so you'd probably have to do
> this over the weekend. Make sure there are no power management settings to
> shut parts of that system down when idle, and test to see if the Internet
> connection goes down.

That is my plan for tonight. I'm going down there in a little while to
connect a newly-formatted PC to the connection. That should be very
informative.

>
> BTW... You don't mention how you get the connection back up when it goes
> down. Are you rebooting the server? Power-cycling the modem? Calling
> Comcast, and having them reset the modem remotely? What does, and what
> doesn't work to bring the connection back up?

That is another strange aspect to the story. For 3 straight days, the modem
began working again during my call to Comcast. I would call in, and after
identifying the customer the Comcast rep would attempt to log in to the
Netgear to "take a look." The router would start working immediately. In
fact, during that 3-4 day stretch, one of the reps and I used the "sleep
mode" analogy, such as you mentioned with the power management suggestions.
However, many Comcast folks have assured me the Netgear has no sleep mode.
This morning when I called in, the Comcast rep offered to reset the modem,
which brought the internet back up. When I said that indicated a problem on
their end (or with their equipment), she reiterated Comcast's position that
since they've swapped the unit out twice the problem MUST be on the client
side. They think something is locking the Netgear up, requiring a reset
sometimes, while other times not.

jm

$Bill
04-30-07, 05:27 PM
JM wrote:
>

I'd start with a separate router and modem setup if possible.
Should make it easier to isolate your problem and it might just go away.

JM
04-30-07, 06:14 PM
"$Bill" <news@SPAMOLAtodbe.com> wrote in message
news:46365f47$0$9942$4c368faf@roadrunner.com...
> JM wrote:
>>
>
> I'd start with a separate router and modem setup if possible.
> Should make it easier to isolate your problem and it might just go away.

Funny you should suggest that, as I just returned from driving halfway to
the customer site to install a Linksys. Instead, I turned around, deciding
to have them turn off the server tonight to see if the gateway still "locks
up" or otherwise stops responding anytime between now and 7:30 a.m tomorrow
morning. I have a ping test monitoring the gateway right now. If the
gateway still has problems with the server and all workstations turned off,
I think Comcast's theory is pretty much debunked.

Agree?

jm

JM
04-30-07, 06:21 PM
After further consideration, I don't see much value in this bit of
troubleshooting. Unless the unit is bad in a manufacturer defect kind of
way (which I seriously doubt, since we're on our third one), there is no way
the unit will fail with no traffic going through it.

As $Bill suggested, perhaps it would have been better for me to go ahead and
install the Linksys and remove the server-as-internet-gateway from the
equation.

jm






"JM" <jake@yahoo.com> wrote in message
news:f_KdnbrJ6sOz96vbnZ2dnUVZ_tmknZ2d@comcast.com...
>
> "$Bill" <news@SPAMOLAtodbe.com> wrote in message
> news:46365f47$0$9942$4c368faf@roadrunner.com...
>> JM wrote:
>>>
>>
>> I'd start with a separate router and modem setup if possible.
>> Should make it easier to isolate your problem and it might just go away.
>
> Funny you should suggest that, as I just returned from driving halfway to
> the customer site to install a Linksys. Instead, I turned around,
> deciding to have them turn off the server tonight to see if the gateway
> still "locks up" or otherwise stops responding anytime between now and
> 7:30 a.m tomorrow morning. I have a ping test monitoring the gateway
> right now. If the gateway still has problems with the server and all
> workstations turned off, I think Comcast's theory is pretty much debunked.
>
> Agree?
>
> jm
>
>
>
>
>
>
>

$Bill
04-30-07, 08:53 PM
JM wrote:
> "$Bill" <news@SPAMOLAtodbe.com> wrote in message
> news:46365f47$0$9942$4c368faf@roadrunner.com...
>
>>JM wrote:
>>
>>I'd start with a separate router and modem setup if possible.
>>Should make it easier to isolate your problem and it might just go away.
>
>
> Funny you should suggest that, as I just returned from driving halfway to
> the customer site to install a Linksys. Instead, I turned around, deciding
> to have them turn off the server tonight to see if the gateway still "locks
> up" or otherwise stops responding anytime between now and 7:30 a.m tomorrow
> morning. I have a ping test monitoring the gateway right now. If the
> gateway still has problems with the server and all workstations turned off,
> I think Comcast's theory is pretty much debunked.
>
> Agree?

It would go a long way towards it if indeed all the LAN equipment is off,
but that really doesn't solve anything.

Next try sticking that Linksys in and reconfiguring the Netgear as a
plain router (I assume that can be done) or replace it with a another
router.

JM
04-30-07, 09:30 PM
"$Bill" <news@SPAMOLAtodbe.com> wrote in message
news:46368f89$0$4670$4c368faf@roadrunner.com...
> JM wrote:
>> "$Bill" <news@SPAMOLAtodbe.com> wrote in message
>> news:46365f47$0$9942$4c368faf@roadrunner.com...
>>
>>>JM wrote:
>>>
>>>I'd start with a separate router and modem setup if possible.
>>>Should make it easier to isolate your problem and it might just go away.
>>
>>
>> Funny you should suggest that, as I just returned from driving halfway to
>> the customer site to install a Linksys. Instead, I turned around,
>> deciding to have them turn off the server tonight to see if the gateway
>> still "locks up" or otherwise stops responding anytime between now and
>> 7:30 a.m tomorrow morning. I have a ping test monitoring the gateway
>> right now. If the gateway still has problems with the server and all
>> workstations turned off, I think Comcast's theory is pretty much
>> debunked.
>>
>> Agree?
>
> It would go a long way towards it if indeed all the LAN equipment is off,
> but that really doesn't solve anything.
>
> Next try sticking that Linksys in and reconfiguring the Netgear as a
> plain router (I assume that can be done) or replace it with a another
> router.

The Netgear is provided by Comcast. It's a combo router/cable modem, and
it's the only device they offer for business use with static IP.

jm

$Bill
04-30-07, 10:44 PM
JM wrote:
>
> The Netgear is provided by Comcast. It's a combo router/cable modem, and
> it's the only device they offer for business use with static IP.

Borrow one or buy your own for $40 and sell it later if need be. At least
you'll have a chance of finding the problem for $40 (or less if you pass
it on when you're done) and I assume you already own the Linksys.

If it works with your equipment, they won't be able to pass the buck.

JM
04-30-07, 11:09 PM
"$Bill" <news@SPAMOLAtodbe.com> wrote in message
news:4636a9a9$0$8996$4c368faf@roadrunner.com...
> JM wrote:
>>
>> The Netgear is provided by Comcast. It's a combo router/cable modem, and
>> it's the only device they offer for business use with static IP.
>
> Borrow one or buy your own for $40 and sell it later if need be. At least
> you'll have a chance of finding the problem for $40 (or less if you pass
> it on when you're done) and I assume you already own the Linksys.
>
> If it works with your equipment, they won't be able to pass the buck.

I asked about this a few days ago, and they told me they do not allow
customer-owned cable modems. I pressed the issue with another csr, who
insisted they cannot do this, since there is no way for them to provision
the service on equipment other than theirs. She asked me, "How in the world
would we configure it?"

jm

$Bill
05-01-07, 01:23 AM
$Bill wrote:
> JM wrote:
>
>>
>> The Netgear is provided by Comcast. It's a combo router/cable modem,
>> and it's the only device they offer for business use with static IP.
>
>
> Borrow one or buy your own for $40 and sell it later if need be. At least
> you'll have a chance of finding the problem for $40 (or less if you pass
> it on when you're done) and I assume you already own the Linksys.
>
> If it works with your equipment, they won't be able to pass the buck.

It just dawned on me that you didn't say wether your Linksys was a modem
or router - I had assumed modem.

$Bill
05-01-07, 02:31 AM
JM wrote:
>
> I asked about this a few days ago, and they told me they do not allow
> customer-owned cable modems. I pressed the issue with another csr, who
> insisted they cannot do this, since there is no way for them to provision
> the service on equipment other than theirs. She asked me, "How in the world
> would we configure it?"

That's got to be both the funniest and stupidest thing I've heard lately.
Who trains these people ?

You should have told her the same way every other ISP does it. :)

Warren H
05-01-07, 11:12 AM
$Bill wrote:
> JM wrote:
>>
>> I asked about this a few days ago, and they told me they do not allow
>> customer-owned cable modems. I pressed the issue with another csr,
>> who insisted they cannot do this, since there is no way for them to
>> provision the service on equipment other than theirs. She asked me,
>> "How in the world would we configure it?"
>
> That's got to be both the funniest and stupidest thing I've heard
> lately.
> Who trains these people ?
>
> You should have told her the same way every other ISP does it. :)
>

I don't think she meant that it wasn't possible in the global sense, but
rather it isn't something that they're allowed to do, and there aren't
any work-arounds, either.

I don't know why Comcast requires that those business-class customers
use only the modem that they provide, or why they chose that particular
modem. I suspect it has to do with an SLA, and their need to minimize
the variables out of their control.

But it's not a training issue. The company could provision a
customer-owned modem, but they've chosen not to allow the agents that
ability. So they, the agents, don't have any way "in the world" to
provision it, but that's probably not the best way she could have gotten
that point across.

BTW, this brings up another point. Is there an SLA in the contract? The
cost of business-class service has gone down considerably in most
markets, and that may be because they only include priority support, and
not an SLA these days But I suspect that if there is an SLA, it would
have something to do with the modem being up, but not necessarily
anything beyond. If there's an SLA, they would probably keep records to
protect their liability, and those records might also be available to
the agent. I'd ask what they show. And if there is no SLA, and they
don't keep those kinds of records, there ought to still be a way to
escalate the issue to the NOC, and have them do such monitoring.

It would be hard for a customer to do the monitoring themselves. A
DOCSIS cable modem has an IP address on it's WAN side. Normally it's a
class A private range IP address, so monitoring the modem would require
being on their network. And it would also require knowing what the
modem's IP address is, and that's not something that there is any way
for the customer to discover. Perhaps the CRS is able to see what that
IP address is, but it's also possible the tools they have hide that
address as well.

I'm also curious about what the modem's indicator lights are indicating
during the problems. And I also wonder what the modem logs show.
Confirming that it's a TCP/IP problem, and not an RF problem (or vice
versa) is an important step that should have already been taken. (And
probably was, but, hey, if we're brainstorming...)

--
Warren H.

==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.

Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker

JM
05-01-07, 07:03 PM
"Warren H" <wholzem@hotmail.com> wrote in message
news:r_KdnSlLmv9yxarbnZ2dnUVZ_jCdnZ2d@comcast.com...
> $Bill wrote:
>> JM wrote:
>>>
>>> I asked about this a few days ago, and they told me they do not allow
>>> customer-owned cable modems. I pressed the issue with another csr, who
>>> insisted they cannot do this, since there is no way for them to
>>> provision the service on equipment other than theirs. She asked me,
>>> "How in the world would we configure it?"
>>
>> That's got to be both the funniest and stupidest thing I've heard lately.
>> Who trains these people ?
>>
>> You should have told her the same way every other ISP does it. :)
>>
>
> I don't think she meant that it wasn't possible in the global sense, but
> rather it isn't something that they're allowed to do, and there aren't any
> work-arounds, either.
>
> I don't know why Comcast requires that those business-class customers use
> only the modem that they provide, or why they chose that particular modem.
> I suspect it has to do with an SLA, and their need to minimize the
> variables out of their control.
>
> But it's not a training issue. The company could provision a
> customer-owned modem, but they've chosen not to allow the agents that
> ability. So they, the agents, don't have any way "in the world" to
> provision it, but that's probably not the best way she could have gotten
> that point across.
>
> BTW, this brings up another point. Is there an SLA in the contract? The
> cost of business-class service has gone down considerably in most markets,
> and that may be because they only include priority support, and not an SLA
> these days But I suspect that if there is an SLA, it would have something
> to do with the modem being up, but not necessarily anything beyond. If
> there's an SLA, they would probably keep records to protect their
> liability, and those records might also be available to the agent. I'd ask
> what they show. And if there is no SLA, and they don't keep those kinds of
> records, there ought to still be a way to escalate the issue to the NOC,
> and have them do such monitoring.
>
> It would be hard for a customer to do the monitoring themselves. A DOCSIS
> cable modem has an IP address on it's WAN side. Normally it's a class A
> private range IP address, so monitoring the modem would require being on
> their network. And it would also require knowing what the modem's IP
> address is, and that's not something that there is any way for the
> customer to discover. Perhaps the CRS is able to see what that IP address
> is, but it's also possible the tools they have hide that address as well.
>
> I'm also curious about what the modem's indicator lights are indicating
> during the problems. And I also wonder what the modem logs show.
> Confirming that it's a TCP/IP problem, and not an RF problem (or vice
> versa) is an important step that should have already been taken. (And
> probably was, but, hey, if we're brainstorming...)
>

The activities of the front panel lights don't tell me anything, although
I'm not sure I would know what I'm looking at anyway. The power light is
on, of course, as the "network" light (as the csr called it), indicating
sync with the ISP. Then there two opposing "lightening bolt" lights
(upstream/downstream) that flicker contstantly. They seem to flicker 3
times in unison, and then several times alternating. Then there are
numbered lights for the lan ports connected.

As for network monitoring, I asked about that, and, you're correct, it's not
something they can do from their local help desk. They simply don't have
the tools. I had another support group on the phone on Saturday, and she
actually referred to the "real" IP address, not our static (I wrote it down
if that would do any good). They could not monitor the network traffic,
either. Interestingly, she said her group could not even log in to the
Netgears. Comcast has recently purchased Time Warner - our old ISP - and
Adelphia. There seems to still be a lot of fragmentation.

The question remains: Why is the Netgear locking up? Some Comcast reps
still deny their equipment is ever going off line. But while I was at the
customer site today I proved it again, at least to my satisfaction. The
internet went down, I reset the Netgear, the internet came up.

While Comcast's basic stance is that the problem is on our side (after all,
they've tried 3 Netgears), one event seems to stop them all in their tracks
when I bring it up: Last Thursday during an outage, I called Comcast - as
has been my habit every day for 3 weeks - and the rep was in the process of
logging into the Netgear when the Netgear did a full power reset. For some
reason, this didn't flip my lid. I simply asked the Comcast rep, "What did
you just do?" He answered, "What do you mean?" When I told him the Netgear
powered off and back on, he didn't hesitate: He said, "That's never
supposed to happen. I'll have a tech out shortly." Thus, our 3rd Netgear.

With that in mind, what in the world are my options?

thanks to EVERYONE who has given of their experience and time in helping
brainstorm this issue.


jm

Warren H
05-02-07, 04:43 PM
JM wrote:
> While Comcast's basic stance is that the problem is on our side (after
> all, they've tried 3 Netgears), one event seems to stop them all in
> their tracks when I bring it up: Last Thursday during an outage, I
> called Comcast - as has been my habit every day for 3 weeks - and the
> rep was in the process of logging into the Netgear when the Netgear
> did a full power reset. For some reason, this didn't flip my lid. I
> simply asked the Comcast rep, "What did you just do?" He answered,
> "What do you mean?" When I told him the Netgear powered off and back
> on, he didn't hesitate: He said, "That's never supposed to happen.
> I'll have a tech out shortly." Thus, our 3rd Netgear.


When they replace the modem, are they just replacing the modem, or are
they also replacing the power cord and power supply brick? If they just
swapped the modem itself, the problem piece may be still sitting there.

And what is the power supply plugged into? If it's plugged into a power
strip, surge protector, or UPS, try taking that out of the mix. Plug the
power supply for the modem directly into a normal wall outlet. Use a
heavy-duty extension cord if there isn't one close enough.

In fact, if you can reach an outlet on a different circuit, try that --
especially if there's a laser printer (or any other appliance that
periodically needs to heat-up) plugged into the circuit it's on now.

--
Warren H.

==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.

Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker

w_tom
05-03-07, 07:40 PM
On May 1, 7:03 pm, "JM" <j...@yahoo.com> wrote:
> The activities of the front panel lights don't tell me anything, although
> I'm not sure I would know what I'm looking at anyway. The power light is
> on, of course, as the "network" light (as the csr called it), indicating
> sync with the ISP. Then there two opposing "lightening bolt" lights
> (upstream/downstream) that flicker contstantly. They seem to flicker 3
> times in unison, and then several times alternating. Then there are
> numbered lights for the lan ports connected.
>
> As for network monitoring, I asked about that, and, you're correct, it's not
> something they can do from their local help desk. They simply don't have
> the tools.

Your modem is receiving radio waves. Just like any radio, signal
integrity is determined by signal strength, or more important, Signal
to Noise ratio.

Many cable modems for some reason cannot bother to provide that
critical parameter. Without it, then one can only speculate whether
the cable connection is good or bad. As obvious from responses -
modem 'swappers' are only speculating. Wildly replacing modems
without first learning what is wrong. Without that 'signal to noise'
ratio number, then no one can even know which side of the modem is
failing.

That number is displayed by a modem on a status page. But only if
the cable provider had an engineer (not a bean counter) selecting
modems.

Meanwhile, eliminate other reasons for intermittent operation.
Start with something so often forgotten by untrained cable installers
and that can permit household or neighborhood appliances to create
intermittent failures. That cable must drop down to be connected
'less than 10 feet' to the same earthing electrode that is also 'less
than 10 feet' from the breaker box. Make that earthing connection
before cable enters the building. Connected to an earth ground that
every other utility also connects to; using a ground block (as even
sold in Lowes for $2) and 'less than 10 feet' of 12 AWG wire.

Next, where does that cable wire route. What else connects to it?
An alternative test is to route a wire direct to where cable enters
the building with nothing else connected - and change nothing else.
Does system work more reliable? You would know that immediately if
modem provided S/N ratio numbers. Of course this test performed only
because useful information to identify a fault is (apparently) not
available AND your cable 'tech support' has no idea.

Meanwhile, a computer can connect directly to modem's status page -
constantly. That being one way to monitor customer side of the
modem. When outside connection is lost, is that modem status page
still accessible?

Of course, anything you do to make the problem worse should help
find the failure. Find a failure before trying to fix or replace
anything. Since they did not do that and then replaced modems, what
do you know? Nothing. You don't even know which side of the modem is
problematic because they did not identify a problem before fixing it.
Instead they shotgunned. Therefore nothing useful was learned.
Therefore zero progress has been made. You don't even know what is
good. Everything is still unknown.

If available, get that S/N ratio number that every miminally
acceptable modem (cable, DSL, etc) must report.

JM
05-06-07, 10:50 AM
"w_tom" <w_tom1@usa.net> wrote in message
news:1178235617.893336.88510@y80g2000hsf.googlegroups.com...
> On May 1, 7:03 pm, "JM" <j...@yahoo.com> wrote:
>> The activities of the front panel lights don't tell me anything, although
>> I'm not sure I would know what I'm looking at anyway. The power light is
>> on, of course, as the "network" light (as the csr called it), indicating
>> sync with the ISP. Then there two opposing "lightening bolt" lights
>> (upstream/downstream) that flicker contstantly. They seem to flicker 3
>> times in unison, and then several times alternating. Then there are
>> numbered lights for the lan ports connected.
>>
>> As for network monitoring, I asked about that, and, you're correct, it's
>> not
>> something they can do from their local help desk. They simply don't have
>> the tools.
>
> Your modem is receiving radio waves. Just like any radio, signal
> integrity is determined by signal strength, or more important, Signal
> to Noise ratio.
>
> Many cable modems for some reason cannot bother to provide that
> critical parameter. Without it, then one can only speculate whether
> the cable connection is good or bad. As obvious from responses -
> modem 'swappers' are only speculating. Wildly replacing modems
> without first learning what is wrong. Without that 'signal to noise'
> ratio number, then no one can even know which side of the modem is
> failing.
>
> That number is displayed by a modem on a status page. But only if
> the cable provider had an engineer (not a bean counter) selecting
> modems.
>
> Meanwhile, eliminate other reasons for intermittent operation.
> Start with something so often forgotten by untrained cable installers
> and that can permit household or neighborhood appliances to create
> intermittent failures. That cable must drop down to be connected
> 'less than 10 feet' to the same earthing electrode that is also 'less
> than 10 feet' from the breaker box. Make that earthing connection
> before cable enters the building. Connected to an earth ground that
> every other utility also connects to; using a ground block (as even
> sold in Lowes for $2) and 'less than 10 feet' of 12 AWG wire.
>
> Next, where does that cable wire route. What else connects to it?
> An alternative test is to route a wire direct to where cable enters
> the building with nothing else connected - and change nothing else.
> Does system work more reliable? You would know that immediately if
> modem provided S/N ratio numbers. Of course this test performed only
> because useful information to identify a fault is (apparently) not
> available AND your cable 'tech support' has no idea.
>
> Meanwhile, a computer can connect directly to modem's status page -
> constantly. That being one way to monitor customer side of the
> modem. When outside connection is lost, is that modem status page
> still accessible?
>
> Of course, anything you do to make the problem worse should help
> find the failure. Find a failure before trying to fix or replace
> anything. Since they did not do that and then replaced modems, what
> do you know? Nothing. You don't even know which side of the modem is
> problematic because they did not identify a problem before fixing it.
> Instead they shotgunned. Therefore nothing useful was learned.
> Therefore zero progress has been made. You don't even know what is
> good. Everything is still unknown.
>
> If available, get that S/N ratio number that every miminally
> acceptable modem (cable, DSL, etc) must report.


Thank you for your reply.

I cannot access the modem's config, but Comcast (both locally and the level
2 guys in their Denver NOC) insist that their levels (S/N, upstream,
downstream) are all "within spec." And, regarding their support, I've now
spoken to more knowledgeable, more sincere Comcast people, and I'm convinced
for the most part that they are simply as stumped as I am about this whole
deal.

How strange is this: Every morning the internet is down. I can neither
access the lan nor ping the modem's gateway address remotely during this
time. However, as soon as I call Comcast and the support person pulls up
the portal to "take a look," the internet starts working again.

It's the most bizarre thing. It's as if the modem is going to sleep at
night. However, in Comcast's software the modem shows to be online the
entire time.

jm

w_tom
05-06-07, 01:47 PM
Comcast on their end only sees their connection to line amplifiers.
That number only says whether everyone is getting connected. It says
zero about a connection only on your end.

Again, your problem is classic of intermittents which is why a
provider should provide S/N ratios on your modem that you can
monitor. Did the Comcast tech look at signal strength from modem
while standing in the room - or instead only with his measuring
equipment? Modem can report valid and useful number. Their equipment
can only report what modem 'might' see - and not from their equipment
on other side of amplifiers.

Remember a trend among techs. It was never a problem elsewhere;
therefore it is not your problem.

Listed were numerous things to perform. Did they confirm above
listed connections? Your post did not reply to what can create a
significant problem and can only be identified by visual inspection..
And yes, many techs do not appreciate the engineering even in simple
earthing. Often because it did not cause a problem elsewhere;
therefore is not your problem. Did they perform the 'reroute' test?
If not, then why not? Is existing cable good only because they know
it must be good?

Meanwhile, what did you do to verify a problem does not exist on
subscriber side of modem? For example, as your computer pings the
modem constantly, what happens to ping (the numbers) both when
connections are working and not?.

Again, their levels can always look good. But only valid number is
S/N number read directly from your modem. Any only valid number is
both when connection is working and has failed. That number must be
measured on your end of wire and is only useful if read directly by
modem. That number read anywhere else says nothing about your unique
connection.

Your post implies a "we have done everything and nothing is wrong"
attitude. One indication of a bad attitude is no numbers taken when
system is both working AND while failure is ongoing. But again, who
confirmed the earthing connection? I don't see the results of an
inspection so critical that I posted it. Who monitored the S/N
numbers both when modem is working AND when a failure occurs? And who
did same thing using ping from subscriber side - and collected numbers
from that ping both when connections are good and bad? Nothing in
that previous post can be ignored if the problem is to be solved.
Nothing in the last post says to me that technicians are really
looking for a problem.

On May 6, 10:50 am, "JM" <jakem38671omitt...@yahoo.com> wrote:
> I cannot access the modem's config, but Comcast (both locally and the level
> 2 guys in their Denver NOC) insist that their levels (S/N, upstream,
> downstream) are all "within spec." And, regarding their support, I've now
> spoken to more knowledgeable, more sincere Comcast people, and I'm convinced
> for the most part that they are simply as stumped as I am about this whole
> deal.
>
> How strange is this: Every morning the internet is down. I can neither
> access the lan nor ping the modem's gateway address remotely during this
> time. However, as soon as I call Comcast and the support person pulls up
> the portal to "take a look," the internet starts working again.
>
> It's the most bizarre thing. It's as if the modem is going to sleep at
> night. However, in Comcast's software the modem shows to be online the
> entire time.

Warren H
05-06-07, 06:27 PM
w_tom wrote:
> Comcast on their end only sees their connection to line amplifiers.
> That number only says whether everyone is getting connected. It says
> zero about a connection only on your end.

Not true. At any given moment, they can tell how many modems are up (and
down) on each node, and which ones they are. This is at the IP level.


> Again, your problem is classic of intermittents which is why a
> provider should provide S/N ratios on your modem that you can
> monitor. Did the Comcast tech look at signal strength from modem
> while standing in the room - or instead only with his measuring
> equipment? Modem can report valid and useful number. Their equipment
> can only report what modem 'might' see - and not from their equipment
> on other side of amplifiers.

Again, not so. Their monitoring equipment can tell what each modem is
reporting.


> Remember a trend among techs. It was never a problem elsewhere;
> therefore it is not your problem.
>
> Listed were numerous things to perform. Did they confirm above
> listed connections? Your post did not reply to what can create a
> significant problem and can only be identified by visual inspection..
> And yes, many techs do not appreciate the engineering even in simple
> earthing. Often because it did not cause a problem elsewhere;
> therefore is not your problem. Did they perform the 'reroute' test?
> If not, then why not? Is existing cable good only because they know
> it must be good?
>
> Meanwhile, what did you do to verify a problem does not exist on
> subscriber side of modem? For example, as your computer pings the
> modem constantly, what happens to ping (the numbers) both when
> connections are working and not?.
>
> Again, their levels can always look good. But only valid number is
> S/N number read directly from your modem. Any only valid number is
> both when connection is working and has failed. That number must be
> measured on your end of wire and is only useful if read directly by
> modem. That number read anywhere else says nothing about your unique
> connection.

What the agents on the phone see is what the modem is reporting. It is
not a measurement from their end. It is the numbers that the modem
itself reports back.


> Your post implies a "we have done everything and nothing is wrong"
> attitude. One indication of a bad attitude is no numbers taken when
> system is both working AND while failure is ongoing. But again, who
> confirmed the earthing connection? I don't see the results of an
> inspection so critical that I posted it. Who monitored the S/N
> numbers both when modem is working AND when a failure occurs? And who
> did same thing using ping from subscriber side - and collected numbers
> from that ping both when connections are good and bad? Nothing in
> that previous post can be ignored if the problem is to be solved.
> Nothing in the last post says to me that technicians are really
> looking for a problem.

This whole idea that it has to be a grounding problem is quite a
long-shot, and really doesn't fit with the symptoms reported to this
point. However since we're all starting to run out of ideas, and
practical isolation troubleshooting hasn't been very fruitful, he might
as well start checking random long-shots.

I also don't detect any bad attitude on his part. What I see is that he
tried everything he could think of (which is different from everything),
and still has not found the problem, and is therefore trying to
backtrack, and look for things that may have missed. Hardly the "bad
attitude" you're attributing to him. If anything, his attitude is better
than most of the people who post problems here.

--
Warren H.

==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.

Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker

JM
05-06-07, 09:44 PM
> Comcast on their end only sees their connection to line amplifiers.
> That number only says whether everyone is getting connected. It says
> zero about a connection only on your end.

I'm no expert on internet/WAN, by any means, but I don't believe you are
correct on this point. Even the local first-tier support people can log
directly into the modem using what I believe they call PSV, peruse the
settings, readings, config, etc. Granted, the information they glean
appears to be rather limited - compared to the NOCs of other providers with
whom I've worked - but I think you are describing Comcast's support as much
more "in the dark" than they actually are.


> Again, your problem is classic of intermittents which is why a
> provider should provide S/N ratios on your modem that you can
> monitor. Did the Comcast tech look at signal strength from modem
> while standing in the room - or instead only with his measuring
> equipment? Modem can report valid and useful number. Their equipment
> can only report what modem 'might' see - and not from their equipment
> on other side of amplifiers.

I'm not following the reasoning.


> Remember a trend among techs. It was never a problem elsewhere;
> therefore it is not your problem.

I respectfully disagree with this generalization. I have been a technician
for seven years, and I used to operate a team of 13 telecom technicians. In
general, technicians try to solve problems to the best of their ability.
Your characterization is the exception, in my experience.


> Listed were numerous things to perform. Did they confirm above
> listed connections? Your post did not reply to what can create a
> significant problem and can only be identified by visual inspection..
> And yes, many techs do not appreciate the engineering even in simple
> earthing. Often because it did not cause a problem elsewhere;
> therefore is not your problem. Did they perform the 'reroute' test?
> If not, then why not? Is existing cable good only because they know
> it must be good?

Several issues here. First of all, I have not had time to distill your
suggestions and put them into context. Secondly, Comcast is not simpy going
to execute every list of suggestions that might come their way. Third,
while I sincerely appreciate your willingness to help, and I respect your
expertise, I do not believe your earthing theory is valid. The reason is
that cable internet has been functioning perfectly in this location for
years. Only within the past 3 weeks have the problems arisen. While I'm no
electrician, I do understand the basics of electricity and grounding, and I
do not see how this factor bears on an internet connection's reliability
after working so well in the past. However, I may be missing something, and
I welcome your arguments to the contrary.


> Meanwhile, what did you do to verify a problem does not exist on
> subscriber side of modem? For example, as your computer pings the
> modem constantly, what happens to ping (the numbers) both when
> connections are working and not?


This is a valid question, and there is much to say here when I have a little
more time, but for now I want to ask: What are some examples of problems on
the subscriber side might cause intermittent internet?


> Again, their levels can always look good. But only valid number is
> S/N number read directly from your modem. Any only valid number is
> both when connection is working and has failed. That number must be
> measured on your end of wire and is only useful if read directly by
> modem. That number read anywhere else says nothing about your unique
> connection.

> Your post implies a "we have done everything and nothing is wrong"
> attitude.

To some degree. However, more accurately, the attitude is: "Yes, something
is wrong. We have caught our modem offline a time or two. However, for the
most part our equipment shows your modem to be online. Whatever is causing
the Netgear to stop responding is a result of a problem on your LAN side."

They do not disagree that something is affecting the performance of their
Netgear modem. They just don't think the problem is "their fault."


>One indication of a bad attitude is no numbers taken when
> system is both working AND while failure is ongoing. But again, who
> confirmed the earthing connection? I don't see the results of an
> inspection so critical that I posted it. Who monitored the S/N
> numbers both when modem is working AND when a failure occurs? And who
> did same thing using ping from subscriber side - and collected numbers
> from that ping both when connections are good and bad? Nothing in
> that previous post can be ignored if the problem is to be solved.
> Nothing in the last post says to me that technicians are really
> looking for a problem.

Without re-reading all my posts on this issue, I'm not sure what details of
included and left out. However, I can say with certainty that everyone
involved is "looking for a problem." They/we may not be looking in the way
you would look, but that doesn't negate the effort.

And please clarify your suggestion regarding recording ping results from
subscriber side when connections are good and bad. Ping what? When the
internet is down, the Netgear [usually but not always] will not respond to a
ping, either from within or from the outside. Perhaps I've missed your
point.

Thank you for your determination to help.

jm

















>
> On May 6, 10:50 am, "JM" <jakem38671omitt...@yahoo.com> wrote:
>> I cannot access the modem's config, but Comcast (both locally and the
>> level
>> 2 guys in their Denver NOC) insist that their levels (S/N, upstream,
>> downstream) are all "within spec." And, regarding their support, I've
>> now
>> spoken to more knowledgeable, more sincere Comcast people, and I'm
>> convinced
>> for the most part that they are simply as stumped as I am about this
>> whole
>> deal.
>>
>> How strange is this: Every morning the internet is down. I can neither
>> access the lan nor ping the modem's gateway address remotely during this
>> time. However, as soon as I call Comcast and the support person pulls up
>> the portal to "take a look," the internet starts working again.
>>
>> It's the most bizarre thing. It's as if the modem is going to sleep at
>> night. However, in Comcast's software the modem shows to be online the
>> entire time.
>

JM
05-06-07, 09:55 PM
"Warren H" <wholzem@hotmail.com> wrote in message
news:nPGdnb9qNML4y6PbnZ2dnUVZ_hynnZ2d@comcast.com...
> w_tom wrote:
>> Comcast on their end only sees their connection to line amplifiers.
>> That number only says whether everyone is getting connected. It says
>> zero about a connection only on your end.
>
> Not true. At any given moment, they can tell how many modems are up (and
> down) on each node, and which ones they are. This is at the IP level.
>
>
>> Again, your problem is classic of intermittents which is why a
>> provider should provide S/N ratios on your modem that you can
>> monitor. Did the Comcast tech look at signal strength from modem
>> while standing in the room - or instead only with his measuring
>> equipment? Modem can report valid and useful number. Their equipment
>> can only report what modem 'might' see - and not from their equipment
>> on other side of amplifiers.
>
> Again, not so. Their monitoring equipment can tell what each modem is
> reporting.
>
>
>> Remember a trend among techs. It was never a problem elsewhere;
>> therefore it is not your problem.
>>
>> Listed were numerous things to perform. Did they confirm above
>> listed connections? Your post did not reply to what can create a
>> significant problem and can only be identified by visual inspection..
>> And yes, many techs do not appreciate the engineering even in simple
>> earthing. Often because it did not cause a problem elsewhere;
>> therefore is not your problem. Did they perform the 'reroute' test?
>> If not, then why not? Is existing cable good only because they know
>> it must be good?
>>
>> Meanwhile, what did you do to verify a problem does not exist on
>> subscriber side of modem? For example, as your computer pings the
>> modem constantly, what happens to ping (the numbers) both when
>> connections are working and not?.
>>
>> Again, their levels can always look good. But only valid number is
>> S/N number read directly from your modem. Any only valid number is
>> both when connection is working and has failed. That number must be
>> measured on your end of wire and is only useful if read directly by
>> modem. That number read anywhere else says nothing about your unique
>> connection.
>
> What the agents on the phone see is what the modem is reporting. It is not
> a measurement from their end. It is the numbers that the modem itself
> reports back.
>
>
>> Your post implies a "we have done everything and nothing is wrong"
>> attitude. One indication of a bad attitude is no numbers taken when
>> system is both working AND while failure is ongoing. But again, who
>> confirmed the earthing connection? I don't see the results of an
>> inspection so critical that I posted it. Who monitored the S/N
>> numbers both when modem is working AND when a failure occurs? And who
>> did same thing using ping from subscriber side - and collected numbers
>> from that ping both when connections are good and bad? Nothing in
>> that previous post can be ignored if the problem is to be solved.
>> Nothing in the last post says to me that technicians are really
>> looking for a problem.
>
> This whole idea that it has to be a grounding problem is quite a
> long-shot, and really doesn't fit with the symptoms reported to this
> point. However since we're all starting to run out of ideas, and practical
> isolation troubleshooting hasn't been very fruitful, he might as well
> start checking random long-shots.
>
> I also don't detect any bad attitude on his part. What I see is that he
> tried everything he could think of (which is different from everything),
> and still has not found the problem, and is therefore trying to backtrack,
> and look for things that may have missed. Hardly the "bad attitude" you're
> attributing to him. If anything, his attitude is better than most of the
> people who post problems here.
>

Thank you, Warren, but I do not believe he meant that I have a bad attitude.
My reading of his post indicates he is ascribing that attitude to the
Comcast folks. But, maybe not ; ))

This problem is as perplexing as I've ever seen, and I've been around
networks 5-6 days a week for the past 7 years. At this point, several facts
stand out:

- the internet is down every morning
- when I cannot ping the gateway address remotely, the modem shows online in
Comcast's equipment and their constant ping shows no or very little packet
loss
- when they "poll" the modem with their software, as I'm on the phone with
them, the Netgear wakes up and in mid execution my pings start getting
replies and internet service resumes (this one really makes me shake my
head)
- within the past couple of months, the client's domain has turned up on
some ISPs blocked list as possible spammers

I'm now a bit confused as to what information I've included in what posts,
but I can elaborate on that last fact if you think it might bear on the
problem.

thank you so much for your willingness to assist.

jm

Warren H
05-07-07, 12:57 AM
"JM" <jake@yahoo.com> wrote in message
news:zNadnYR9wZOiGqPbnZ2dnUVZ_uiknZ2d@comcast.com...
> Thank you, Warren, but I do not believe he meant that I have a bad
> attitude. My reading of his post indicates he is ascribing that
> attitude to the Comcast folks. But, maybe not ; ))
>
> This problem is as perplexing as I've ever seen, and I've been around
> networks 5-6 days a week for the past 7 years. At this point, several
> facts stand out:
>
> - the internet is down every morning
> - when I cannot ping the gateway address remotely, the modem shows
> online in Comcast's equipment and their constant ping shows no or very
> little packet loss
> - when they "poll" the modem with their software, as I'm on the phone
> with them, the Netgear wakes up and in mid execution my pings start
> getting replies and internet service resumes (this one really makes me
> shake my head)
> - within the past couple of months, the client's domain has turned up
> on some ISPs blocked list as possible spammers
>
> I'm now a bit confused as to what information I've included in what
> posts, but I can elaborate on that last fact if you think it might
> bear on the problem.
>
> thank you so much for your willingness to assist.


I'm leaning towards going back to the idea of disconnecting their
systems from the network, and just connecting a clean PC, and seeing if
the problem appears under those conditions.

I think you've stumbled upon an interesting thing with the rogue
connection to send e-mail. I wonder if there are other processes
running, too.

Frankly, I'm running out of ideas, but if you can't unequivocally show
that the problem is with Comcast, switching to DSL may just be a futile
move.

--
Warren H.

==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.

Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker

w_tom
05-07-07, 04:44 AM
Important information that I did not see earlier:
> When the internet is down, the Netgear [usually but
> not always] will not respond to a ping, either from
> within or from the outside.

IOW the Netgear modem has an IP address from your house and cable
company AND has a completely different IP address from LAN -
subscriber's computer. Subscriber may ping to 192.168.1.1 to 'see'
the modem. You may use 216.123.456.23 to ping same modem from other
side. As I now understand your statement, ping works from both sides
or fails on both sides - simultaneously. Is that correct?

Again, cable techs only do what they have done previously.
Therefore, did they run a wire directly from that Netgear, out the
window, and directly to their cable? Typically they don't do it
because it was never necessary previously. Therefore it is one of the
first things I do. Part of breaking a problem down into parts and
then testing those separated parts.

Same concept applies in this paragraph. If grounding is not
verified visually, then a new machine in a nearby other building or
distant utility load changing early every morning may create current
loops in this building. Why must all incoming utilities connect to
the same ground? Among different things performed by a ground so that
electrical problems in other buildings do not adversely affect your
signals. And since inspection takes only minutes, it is usually one
of the first things we look at - when technicians are totally
confused.

Why is grounding important. Well grounding for safety is understood
by electricians. But that grounding also does things that
electricians typically need not understand. Electrician is a
technician who is carefully trained into how to respond to code. Ask
an electrician how to lower impedance in a wire? He would not know.
He knows what meets code. But can he explain why that ground would
eliminate radio frequency noise from a neighbors new machine? To know
that, he would have to learn things beyond what is in code books.

Comcast is better than most cable companies. For example, Comcast
trained their installers to make that ground connection. But there
are still bad installations out there that can only be found by visual
inspection. Improper grounding may, for example, cause rare voltage
spikes to saturate an RF amp. Does that make sense to you? Does not
matter. Checking grounds are an automatic first inspection when
strange things are occurring.

My experience is that cable company does not read meter's analog
numbers - the decibel numbers. They simply say an IP address responds
- therefore modem is 100% OK. - a GoNogo test. But in a real world,
something can 1) respond when signal is sufficient, 2) not respond
when signal is way too low, AND 3) respond when signal is too low.
This world is ternary. That third state is only detectable from
signal strength numbers - both incoming and outgoing - and read from
modem. Assume numbers to be read by Comcast are intermittently
insufficient. They must read and be able to tell you what outgoing
and especially what incoming signal strength numbers are at any
moment. Are they reading signal strength? Well when signal strength
is too low, then Comcast would not see it. They would only see
numbers when numbers are sufficient. Just one example of why I
posted:
> Again, your problem is classic of intermittents which is
> why a provider should provide S/N ratios on your modem
> that you can monitor.

If their answer is 'it is good', then you want to know 'how good'.
Any answer without numbers reports nothing useful. No numbers is
symptomatic of Go-Nogo testing such as ping. Ping would not report
the third of three states listed later.

When your signal strength drops periodically (due to noise bursts that
a missing ground would have eliminated, or due to periodic frequency
shifting, or interference from a neighbors TV, etc), then what will a
remotely located cable tech see? Nothing useful because bad numbers
cannot be read remotely when modem has temporarily failed. An
intermittent failure due to a missing ground, an improperly routed
cable wire inside the building, etc.

Moving on, if Netgear completely stops responding to pings on both
sides and restore on both sides, well, then who is sending a master
reset to the modem? Does he know his test sends a master reset? Yes,
techs do try to solve to the best of their abilities. But how many
know (for example) why proper grounding is essential - what it
accomplishes? Many techs know "When this happens, then we do
this." Therefore many techs don't know what a "we do this" actually
does. Or whether a DOSCIS signal can cause a modem to perform a
master reset.

Every tech does the best he can. But how many are actually familiar
with the DOSCIS standard? IOW they do the best they can which is
"when this happens, then we do that". Why? Not relevant to many
techs which is why, for example, a tech might never understand the
long list of reasons why all incoming wires (AC electric, phone,
cable) must be grounded to a common point. Also would not know why
many electricians also do not know all the reasons for a common
ground.

Moving on again. Modem is down on this morning. What happens when
the modem is power cycled - meaning even power plug is completely
disconnected and reconnected. Does that restore the signal? Does
that permit ping to occur from both sides? Does that restore signal
strength? IOW does modem start working - respond to pings from both
sides when a power-on master reset occurs? OK. Does Comcast reset it
from a remote center. Does power-in reset also do same? (again this
assumes only two possible conditions: modem is both side locked out
and both sides functional.)

What from the subscribers (LAN) side could cause problems? Well I
am limiting this to answers that only explain a crashed modem on both
LAN and Comcast sides simultaneously. For example, a mismatch in
twisted wires for an Ethernet cable could cause problems - but
typically not crash the modem.

Electrically, a voltage must be so high to overwhelm galvanic
isolation inside that ethernet port - such as static electric
discharge from a human. Or noise frequency must be sufficiently
high. I am not fully familiar with the Netgear modem (and could not
find that necessary status page that I believe Comcast intentionally
did not provide). Therefore I am not aware of any simple command that
can lock out ports without some complex human interaction.

Only LAN side event I know of that can lock out the entire modem?
Excessive voltage spike. BTW, same could happen on cable side of
modem because cable wire was not properly grounded.

Doing the same test as should have been done on cable side of
modem. All LAN cables, except one, would be disconnected the night
before. Is modem locked up that morning? Or temporary cables are
routed through doors and hallways. When not using orginal LAN cables,
does modem no longer lock?

And finally, what can you do to make this problem worse? Heat modem
with a hairdryer on high? I will be unable to suggest in this
paragraph because the scene is too far away. Heating modem with a
hairdryer demonstrates the tone of that suggestion. I don't really
believe heat will yield anything useful. But is there something
unique in that room that when exaggerated, would make failure more
frequent? More frequent failures are easier to solve.

On May 6, 9:44 pm, "JM" <j...@yahoo.com> wrote:
> ...
> I'm no expert on internet/WAN, by any means, but I don't believe you are
> correct on this point. Even the local first-tier support people can log
> directly into the modem using what I believe they call PSV, peruse the
> settings, readings, config, etc. Granted, the information they glean
> appears to be rather limited - compared to the NOCs of other providers with
> whom I've worked - but I think you are describing Comcast's support as much
> more "in the dark" than they actually are.
> ...
>
> I respectfully disagree with this generalization. I have been a technician
> for seven years, and I used to operate a team of 13 telecom technicians. In
> general, technicians try to solve problems to the best of their ability.
> Your characterization is the exception, in my experience.
> ...
>
> Several issues here. First of all, I have not had time to distill your
> suggestions and put them into context. Secondly, Comcast is not simpy going
> to execute every list of suggestions that might come their way. Third,
> while I sincerely appreciate your willingness to help, and I respect your
> expertise, I do not believe your earthing theory is valid. The reason is
> that cable internet has been functioning perfectly in this location for
> years. Only within the past 3 weeks have the problems arisen. While I'm no
> electrician, I do understand the basics of electricity and grounding, and I
> do not see how this factor bears on an internet connection's reliability
> after working so well in the past. However, I may be missing something, and
> I welcome your arguments to the contrary.
> ...
>
> This is a valid question, and there is much to say here when I have a little
> more time, but for now I want to ask: What are some examples of
> problems on the subscriber side might cause intermittent internet?
> ...
>
> And please clarify your suggestion regarding recording ping results from
> subscriber side when connections are good and bad. Ping what? When the
> internet is down, the Netgear [usually but not always] will not respond to a
> ping, either from within or from the outside. Perhaps I've missed your
> point.
>
> Thank you for your determination to help.

$Bill
05-07-07, 05:52 AM
Warren H wrote:
>
> I'm leaning towards going back to the idea of disconnecting their
> systems from the network, and just connecting a clean PC, and seeing if
> the problem appears under those conditions.

Or just disconnect everything since he has his Linksys router in there now
and that should suffice for the local LAN side to take pings and such.

> I think you've stumbled upon an interesting thing with the rogue
> connection to send e-mail. I wonder if there are other processes
> running, too.
>
> Frankly, I'm running out of ideas, but if you can't unequivocally show
> that the problem is with Comcast, switching to DSL may just be a futile
> move.

Way too early for that I would think.

What happens late/early in the morning that could be a factor ? Cold,
humidity maybe ?

What time were these suspicious emails going out and what time do the
failures occur ? Why would data content bother a modem/router ?

Has any of the infrastructure been swapped out yet besides the modem/router
(wiring, ground block, splitter, etc) ? What are all the components currently
in the path to the pole ?

Etc.

JM
05-08-07, 12:09 AM
"$Bill" <news@SPAMOLAtodbe.com> wrote in message
news:463ef6e3$0$27094$4c368faf@roadrunner.com...
> Warren H wrote:
>>
>> I'm leaning towards going back to the idea of disconnecting their systems
>> from the network, and just connecting a clean PC, and seeing if the
>> problem appears under those conditions.
>
> Or just disconnect everything since he has his Linksys router in there now
> and that should suffice for the local LAN side to take pings and such.

Yes, I was planning on doing that tonight, but I didn't make it down. My
only reservation about this is that if I turn off the LAN equipment (except
for the Linksys) and the modem does not go down, what does that prove? It
would seem to support Comcast's assertion that the problem is on the
client's side, but, on the other hand, is it defensible that a modem should
only work when no traffic is going through it?


>> I think you've stumbled upon an interesting thing with the rogue
>> connection to send e-mail. I wonder if there are other processes running,
>> too.
>>
>> Frankly, I'm running out of ideas, but if you can't unequivocally show
>> that the problem is with Comcast, switching to DSL may just be a futile
>> move.
>
> Way too early for that I would think.

With respect, it's not "way too early" for the client who has been dealing
with no internet access every morning for 3 weeks. They are running out of
patience. And a significant challenge is that much troubleshooting is
required, but I cannot work on it every day, and for the most part I'm all
they've got.


> What happens late/early in the morning that could be a factor ? Cold,
> humidity maybe ?

Perhaps, but the fact remains that this internet connection has been working
fine for years.


> What time were these suspicious emails going out and what time do the
> failures occur ?

I can find no definite relationship.

>Why would data content bother a modem/router ?

The heart of the question, as far as I'm concerned. Comcast has suggested
that the activities of our mail server is causing the problems. And I
continue to repeat your question: What bearing does content and traffic in
general have on the performance (or lack thereof) of a cable modem????


jm

Warren H
05-08-07, 01:48 AM
JM wrote:
>
> The heart of the question, as far as I'm concerned. Comcast has
> suggested that the activities of our mail server is causing the
> problems. And I continue to repeat your question: What bearing does
> content and traffic in general have on the performance (or lack
> thereof) of a cable modem????
>

Have you checked for any snmp packets headed to the modem?

Most modems can also be controlled through an http interface showing to
the LAN side.

Can you get to any of the modem logs at 192.168.100.1 ? How about
192.168.1.1 ?

If we could see the modem logs, we could see why it's going down. Or for
that matter, confirm that it's the modem that's going down.

Just to review, and make sure we've been talking about all the same
things, is this how things are set-up:

Various Computers on the LAN
|
V
The "Server" (which is acting as a router for your LAN, and is assigned
your public static IP)
|
V
The Netgear, which includes a cable modem, and has routing capabilities
that are turned off.
|
V
The CMTS at the headend, which has the gateway IP address for the static
IP used by the server)
|
V
The rest of the world.

Numerous times you've mentioned being unable to ping the gateway. Are
you talking about the CMTS at the headend, or some other device. And
where are you pinging it from? The client's side of the modem, or where
you are in the outside world?

You've also mentioned pinging the modem's IP. A cable modem has a class
A private range IP address facing the HFC side that the provider can use
to manage the modem. That 10.x.x.x address is only going to be
accessible from within the Comcast network. The modem also has an
internal http server (to serve pages with logs and status information)
that's accessible only from the LAN side. It has a class C private range
IP address (192.168.100.1). All other traffic is bridged through the
modem.

If the routing capabilities of the modem are turned off, then all you've
got left is the switch that's between the modem part of the Netgear, and
the Ethernet port. So if the routing capabilities are turned-off,
there's no IP address used for this side of the Netgear.

All in all, at this point the modem logs would probably be the most
useful tool we could use.

--
Warren H.

==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.

Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker




--
Warren H.

==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.

Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker

JM
05-08-07, 01:12 PM
>>
>
> Have you checked for any snmp packets headed to the modem?

not sure how to look for that.


> Most modems can also be controlled through an http interface showing to
> the LAN side.
>
> Can you get to any of the modem logs at 192.168.100.1 ? How about
> 192.168.1.1 ?

The modem is not set up this way. There are two IP addresses associated
with our account: a "gateway" address, which is a Class B ISP address
allocated to the cable modem (in this case a Netgear); and a static IP
address, a Class B ISP address that is allocated for the customer premise
equipment. With RoadRunner/Comcast standard business accounts, the customer
gets one public routable "static" address. So, faik, the only ip address
the Netgear "knows" is the gateway address.


> If we could see the modem logs, we could see why it's going down. Or for
> that matter, confirm that it's the modem that's going down.

That's the thing: Although I have not actually seen the modem logs, Comcast
support says the modem logs (historical data) is not reflecting the outages.
In fact, when I cannot ping the gateway address (and the internet service is
not functioning), the Netgear will show to be "on line." They can be in it,
which they are, because they reset it - then the internet starts working
again.


> Just to review, and make sure we've been talking about all the same
> things, is this how things are set-up:
>
> Various Computers on the LAN
> |
> V
> The "Server" (which is acting as a router for your LAN, and is assigned
> your public static IP)
> |
> V
> The Netgear, which includes a cable modem, and has routing capabilities
> that are turned off.
> |
> V
> The CMTS at the headend, which has the gateway IP address for the static
> IP used by the server)
> |
> V
> The rest of the world.


That was the config until last Tuesday, when I placed a Linksys "behind" the
Netgear. So, from the client side -> out, it looks like this:

Various computers on the LAN
(how did you do that straight up-and-down line ????)
V
Network switch
V
Linksys
V
Netgear cable modem/router
V
Comcast headend equipment


> Numerous times you've mentioned being unable to ping the gateway. Are you
> talking about the CMTS at the headend, or some other device. And where are
> you pinging it from? The client's side of the modem, or where you are in
> the outside world?

When I say "ping the gateway," I'm talking about the gateway IP address
Comcast assigns to the Netgear, i.e, 24.xx.xx.30 (the static IP, which now
is assigned to the Linksys WAN port, is 24.xx.xx.31). There is another IP
address used by Comcast to access the Netgear (I belive it's a 73.xx.xx.xx
address), but they do not refer to it.

I am pinging from my office, which is about 20 miles away. A typical series
of events goes like this: approx 8:15 a.m., someone from the firm (my
client) calls and says the internet is down and can't send/receive email. I
immediately try two things from either my laptop or my main work machine,
both running Windows XP Pro: log into the Linksys at the client site using
a web browser (I have remote GUI mgmt enabled, which I access via static IP
address:port I've chosen); and, ping the Netgear using the gateway address.
Both attempts fail. Then, we do one two things: either have someone on
site to power recycle the Netgear, or (much more commonly) I will call
Comcast and tell them the problem has returned.

It's at this point that things always get sideways. Invariably, Comcast
pulls up the client info and informs me that their "constant ping test"
shows no failure, no packet loss, and the "historical data" shows the
Netgear to have been online for days, with perhaps a minute or two
"interruption" here and there. I ask them to explain to me why I cannot
ping the gateway address, and depending on when I call, to whom I speak, and
the specifics of the incident, I will get various replies. The general
stance is that they do not know why. It must be a problem on our end.
After all, they changed out the Netgear twice, their monitoring reveals no
problems, and all the critical measurements are within spec.

During business hours I get the local support team (the former Time Warner
RoadRunner group). The two techs I've spoken to the most "explain" the
problem in slightly different terms, but the general stance is the same:
Since we cannot identify a problem on our end, it MUST be on your end.

And here's the most disheartening part: Even if we eliminate every
possibility from the client side, Comcast still will not have a solution.


> You've also mentioned pinging the modem's IP. A cable modem has a class A
> private range IP address facing the HFC side that the provider can use to
> manage the modem. That 10.x.x.x address is only going to be accessible
> from within the Comcast network. The modem also has an internal http
> server (to serve pages with logs and status information) that's accessible
> only from the LAN side. It has a class C private range IP address
> (192.168.100.1). All other traffic is bridged through the modem.

I did not realize that a modem configured for static IP/bridge mode still
retains a Class C private address. I will try that later from within the
client's network.


> If the routing capabilities of the modem are turned off, then all you've
> got left is the switch that's between the modem part of the Netgear, and
> the Ethernet port. So if the routing capabilities are turned-off, there's
> no IP address used for this side of the Netgear.

Ah, okay, that's what I was going to ask: Where does that private IP come
from?

> All in all, at this point the modem logs would probably be the most useful
> tool we could use.

I asked about this today, but the tech said it wouldn't do any good.
According to him it just shows the modem being online.

I'm an extremely persistent person - some would say obsessive. But I'm
growing weary with this thing.

jm

Warren H
05-08-07, 02:29 PM
JM wrote:
> The modem is not set up this way. There are two IP addresses
> associated with our account: a "gateway" address, which is a Class B
> ISP address allocated to the cable modem (in this case a Netgear); and
> a static IP address, a Class B ISP address that is allocated for the
> customer premise equipment. With RoadRunner/Comcast standard business
> accounts, the customer gets one public routable "static" address. So,
> faik, the only ip address the Netgear "knows" is the gateway address.
>
>> If we could see the modem logs, we could see why it's going down. Or
>> for that matter, confirm that it's the modem that's going down.
>
> That's the thing: Although I have not actually seen the modem logs,
> Comcast support says the modem logs (historical data) is not
> reflecting the outages. In fact, when I cannot ping the gateway
> address (and the internet service is not functioning), the Netgear
> will show to be "on line." They can be in it, which they are, because
> they reset it - then the internet starts working again.

Not sure why you can't just look at the logs on the modem. Comcast
usually doesn't lock-out the customer from this function of the modem.


>> Just to review, and make sure we've been talking about all the same
>> things, is this how things are set-up:
>>
>> Various Computers on the LAN
>> |
>> V
>> The "Server" (which is acting as a router for your LAN, and is
>> assigned your public static IP)
>> |
>> V
>> The Netgear, which includes a cable modem, and has routing
>> capabilities that are turned off.
>> |
>> V
>> The CMTS at the headend, which has the gateway IP address for the
>> static IP used by the server)
>> |
>> V
>> The rest of the world.
>
>
> That was the config until last Tuesday, when I placed a Linksys
> "behind" the Netgear. So, from the client side -> out, it looks like
> this:
>
> Various computers on the LAN
> (how did you do that straight up-and-down line ????)
> V
> Network switch
> V
> Linksys
> V
> Netgear cable modem/router
> V
> Comcast headend equipment
>
>
>> Numerous times you've mentioned being unable to ping the gateway. Are
>> you talking about the CMTS at the headend, or some other device. And
>> where are you pinging it from? The client's side of the modem, or
>> where you are in the outside world?
>
> When I say "ping the gateway," I'm talking about the gateway IP
> address Comcast assigns to the Netgear, i.e, 24.xx.xx.30 (the static
> IP, which now is assigned to the Linksys WAN port, is 24.xx.xx.31).
> There is another IP address used by Comcast to access the Netgear (I
> belive it's a 73.xx.xx.xx address), but they do not refer to it.


If the Netgear has a public IP address, it must be assigned to the
router portion of the equipment. And if that's the case, it's not
operating as a bridge or a switch, it's actually operating as a router.
And if it's operating as a router, the nature of the traffic coming from
the LAN can affect how it operates, as the metaphoric envelopes nested
in the packets are opened, as oposed to just passing the packet through
like in a bridge.


> I am pinging from my office, which is about 20 miles away. A typical
> series of events goes like this: approx 8:15 a.m., someone from the
> firm (my client) calls and says the internet is down and can't
> send/receive email. I immediately try two things from either my
> laptop or my main work machine, both running Windows XP Pro: log into
> the Linksys at the client site using a web browser (I have remote GUI
> mgmt enabled, which I access via static IP address:port I've chosen);
> and, ping the Netgear using the gateway address. Both attempts fail.
> Then, we do one two things: either have someone on site to power
> recycle the Netgear, or (much more commonly) I will call Comcast and
> tell them the problem has returned.
>
> It's at this point that things always get sideways. Invariably,
> Comcast pulls up the client info and informs me that their "constant
> ping test" shows no failure, no packet loss, and the "historical data"
> shows the Netgear to have been online for days, with perhaps a minute
> or two "interruption" here and there. I ask them to explain to me why
> I cannot ping the gateway address, and depending on when I call, to
> whom I speak, and the specifics of the incident, I will get various
> replies. The general stance is that they do not know why. It must be
> a problem on our end. After all, they changed out the Netgear twice,
> their monitoring reveals no problems, and all the critical
> measurements are within spec.

Okay. Now this is starting to make a little more sense.

The *cable modem* in the Netgear has probably been operating perfectly.
(Or as close to perfectly as practical.) It's not the problem. The
problem is happening in the *router* part of the Netgear. Although this
part may be in the same physical box as the cable modem, it's not
normally something that is monitored on an HFC cable modem system.


> During business hours I get the local support team (the former Time
> Warner RoadRunner group). The two techs I've spoken to the most
> "explain" the problem in slightly different terms, but the general
> stance is the same: Since we cannot identify a problem on our end, it
> MUST be on your end.
>
> And here's the most disheartening part: Even if we eliminate every
> possibility from the client side, Comcast still will not have a
> solution.
>
>
>> You've also mentioned pinging the modem's IP. A cable modem has a
>> class A private range IP address facing the HFC side that the
>> provider can use to manage the modem. That 10.x.x.x address is only
>> going to be accessible from within the Comcast network. The modem
>> also has an internal http server (to serve pages with logs and status
>> information) that's accessible only from the LAN side. It has a class
>> C private range IP address (192.168.100.1). All other traffic is
>> bridged through the modem.
>
> I did not realize that a modem configured for static IP/bridge mode
> still retains a Class C private address. I will try that later from
> within the client's network.

The cable modem part of the equipment is *always* a bridge. It's the
router included in the same box that can be configured differently. But
if it has a public IP address, it's not operating as a bridge. It's
operating as a router.


>> If the routing capabilities of the modem are turned off, then all
>> you've got left is the switch that's between the modem part of the
>> Netgear, and the Ethernet port. So if the routing capabilities are
>> turned-off, there's no IP address used for this side of the Netgear.
>
> Ah, okay, that's what I was going to ask: Where does that private IP
> come from?

There are two private range IP addresses associated with most DOCSIS
cable modems. The class A is assigned to the side facing the HFC
network, and is used by the provider to manage the modem. The class C
address, usually 192.168.100.1, faces the Ethernet side. With the right
firmware, it could also be used to access the modem to manage it, but
rarely - very rarely - is that ever enabled. Typically the firmware will
allow you to access status reports and logs which will be served via
http.


>> All in all, at this point the modem logs would probably be the most
>> useful tool we could use.
>
> I asked about this today, but the tech said it wouldn't do any good.
> According to him it just shows the modem being online.

I tend to believe that now.

It sounds like the problem is in the *router* part of your combination
cable modem-router. And it may not be so much a problem with the router
not acting as intended, but a problem with what's being sent to it from
the LAN. Something is locking-up the router part of the Netgear, not the
cable modem part of the Netgear.

I know you aren't going to have any access to manage the cable modem
part of the Netgear, but how much access do you have to manage the
router portion of the Netgear?

Since you've had three different Netgears, and they all act the same,
replacing the hardware again probably won't make a difference. There may
be a setting that can be changed that will change the way the router
acts, but then the question is why was that setting configured the way
it is, and not the way that resolves the problem. What was it designed
to do?

So even though there may be a setting that can be changed in the Netgear
router, that may not be the correct fix. The correct fix may be to find
out what it is that is being sent to the router to cause it to crash.

This differs from the question of what's being sent to the modem to
cause it to crash. Nothing should cause a simple bridge to crash. But
we're not talking about the simple bridge of the modem crashing. It
seems that the modem is working correctly. It's the more complex router,
which is operating at a higher level on the OSI model that's crashing,
and it's not unheard of for a router to crash in this way. It's not just
passing the packets. It's partially opening them.

So what's in those packets that's causing the *router* (not the modem)
to crash?

That's my diagnosis. But in this case, the treatment goes beyond my
level of training.

Would going to DSL solve the problem? Depends on what kind of equipment
they give you. If they give you a combo modem/router, and that router
has the same hardware or the same settings, it probably won't solve the
problem. But it's also possible that it could remain a problem with
different routers, too because switching the modem type, and the network
it's attached to is just changing things on the wrong side of where the
problem is.

--
Warren H.

==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.

Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker

$Bill
05-08-07, 08:32 PM
Warren H wrote:
>
> So even though there may be a setting that can be changed in the Netgear
> router, that may not be the correct fix. The correct fix may be to find
> out what it is that is being sent to the router to cause it to crash.
>
> This differs from the question of what's being sent to the modem to
> cause it to crash. Nothing should cause a simple bridge to crash. But
> we're not talking about the simple bridge of the modem crashing. It
> seems that the modem is working correctly. It's the more complex router,
> which is operating at a higher level on the OSI model that's crashing,
> and it's not unheard of for a router to crash in this way. It's not just
> passing the packets. It's partially opening them.
>
> So what's in those packets that's causing the *router* (not the modem)
> to crash?
>
> That's my diagnosis. But in this case, the treatment goes beyond my
> level of training.
>
> Would going to DSL solve the problem? Depends on what kind of equipment
> they give you. If they give you a combo modem/router, and that router
> has the same hardware or the same settings, it probably won't solve the
> problem. But it's also possible that it could remain a problem with
> different routers, too because switching the modem type, and the network
> it's attached to is just changing things on the wrong side of where the
> problem is.

I wonder if Netgear has a modem similar to the one he has but separate
from the router ? If so, maybe he could swap the modem-router for just
a modem and use his Linksys for the router and see if there's a change.

What's the model number of this Netgear m-r ? I'm guessing it would
have to be a CG814CPR or similar.

I'm still having problem with that stmt a while back that says they have
to use this specific modem-router and nothing else could possibly be
configured (or some such). There's got to be similar but separate hdw
that they can configure - like a separate Motorola/Linksys modem with a
separate Linksys/Netgear router.

Warren H
05-08-07, 08:54 PM
$Bill wrote:
>
> I wonder if Netgear has a modem similar to the one he has but separate
> from the router ? If so, maybe he could swap the modem-router for
> just
> a modem and use his Linksys for the router and see if there's a
> change.
>
> What's the model number of this Netgear m-r ? I'm guessing it would
> have to be a CG814CPR or similar.
>
> I'm still having problem with that stmt a while back that says they
> have
> to use this specific modem-router and nothing else could possibly be
> configured (or some such). There's got to be similar but separate hdw
> that they can configure - like a separate Motorola/Linksys modem with
> a
> separate Linksys/Netgear router.
>

For residential service, Comcast will allow you to use your own modem.
It doesn't work that way for business service. I'm sure that's mostly a
business, not a technical decision on their part, but there could be
some technical reason that I'm just not aware of.

So a different modem (or modem/router) is a step that Comcast has to be
willing to take in this case.

--
Warren H.

==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.

Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker

w_tom
05-08-07, 10:59 PM
On May 8, 12:09 am, "JM" <jakem38671omitt...@yahoo.com> wrote:
> The heart of the question, as far as I'm concerned. Comcast has suggested
> that the activities of our mail server is causing the problems. And I
> continue to repeat your question: What bearing does content and traffic in
> general have on the performance (or lack thereof) of a cable modem????

Looking at what some Netgear modems report. They don't report
signal to noise ratios - therefore Comcast remote centers may have no
such data contrary to what others have implied. These modems do
report a count of packets transmitted and received along with another
important number - data that counter is reset. Therefore if e-mail
was causing a problem, then number of packets transmitted would be
excessive and obvious.

These are numbers that a tech could provide if he has them. But
again, important numbers that might show a problem are still unknown
because numbers are not being provided AND what the tech uses to say
problem does not exist - both are unknown.

There is no acceptable reason why status information is denied the
subscriber.

Meanwhile, Warren H's explaination - what the various IP addresses
are - should be obvious from client machines using IPCONFIG and
TRACERT commands. If problem is only on the router side, then
various computers on client side cannot ping each other. That test
result also was not reported.

Also not defined is whether modem is in router mode or bridge mode.

Warren H
05-09-07, 01:34 AM
w_tom wrote:
> Meanwhile, Warren H's explaination - what the various IP addresses
> are - should be obvious from client machines using IPCONFIG and
> TRACERT commands. If problem is only on the router side, then
> various computers on client side cannot ping each other. That test
> result also was not reported.

He's using the server as his LAN router. The Netgear router isn't
routing in the lay sense of the word. That is, in the topography of his
network, it's not directing traffic here or there. It is only sitting
there between his server (which is the real router on his LAN), and the
cable modem, but it's opening packets, and repackaging them as a router
does, and not simply passing them through as a bridge would.


> Also not defined is whether modem is in router mode or bridge mode.

I can't find a model number for the piece of equipment, but giving this
more consideration, I don't think it can actually be configured to be a
bridge. I believe that it can only act as a router. It can act as a NAT
router, or it can operate as a normal router. Not normal in the same
since as a "home" or "broadband" router, which normally acts as a NAT
router, but normal as in it routes packets to various public IP
addresses. In this case, there's only one IP address to route to, but
that doesn't mean the equipment stops opening packets like a router
does, and turns into a bridge that doesn't open packets. (Remember that
a router and a bridge operate on different levels of the OSI model.)

Also, if it were just a bridge, there's no ISP that's going to waste a
publicly routable IP address on it. As a bridge, it's IP address would
only be useful for managing the equipment, and would not be a part of
the path through the device. For that, they'd use a private range IP
address just like they do for the cable modem.

The more I think about this issue, assuming that everyone is reporting
honestly, my confidence that it's not the cable modem, and that the
failure is happening because something is crashing the router part of
the Netgear box goes up.

--
Warren H.

==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.

Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker

$Bill
05-09-07, 02:21 AM
w_tom wrote:
>
> These are numbers that a tech could provide if he has them. But
> again, important numbers that might show a problem are still unknown
> because numbers are not being provided AND what the tech uses to say
> problem does not exist - both are unknown.
>
> There is no acceptable reason why status information is denied the
> subscriber.

True.

> Meanwhile, Warren H's explaination - what the various IP addresses
> are - should be obvious from client machines using IPCONFIG and
> TRACERT commands. If problem is only on the router side, then
> various computers on client side cannot ping each other. That test
> result also was not reported.

There's a switch in there and another router now, so that shouldn't
be happening. There may also be a switch on the Netgear ????
Still don't know the model.

Warren H
05-09-07, 03:11 AM
$Bill wrote:
> There may also be a switch on the Netgear ????

Right. If there's more than one Ethernet port, there would be a switch
involved. But a switch operates on an even lower-level than a bridge, so
the chances that it's a switch issue is low. And since the most likely
switch-related issue would be the physical hardware, since three
different Netgear boxes have been used, it's not likely that they all
had the same physical defect.

--
Warren H.

==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.

Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker

$Bill
05-09-07, 06:43 AM
Warren H wrote:
> $Bill wrote:
>
>> There may also be a switch on the Netgear ????
>
>
> Right. If there's more than one Ethernet port, there would be a switch
> involved. But a switch operates on an even lower-level than a bridge, so
> the chances that it's a switch issue is low. And since the most likely
> switch-related issue would be the physical hardware, since three
> different Netgear boxes have been used, it's not likely that they all
> had the same physical defect.

I was referring to the fact that if there is a switch, the packets from
the LAN may not even make it to the router portion. Therefore, no local
LAN pinging problem could exist. And we know there's another switch farther
in that should allow the local PCs to ping each other without a router
getting involved. This in response to Tom's pinging stmt.

JM
05-09-07, 10:41 AM
I'm not sure where to put my responses now.

I just want to thank everyone for their time and effort. I sincerely
appreciate it. Really. I'd be totally on my own without this discussion.


>> Meanwhile, Warren H's explaination - what the various IP addresses
>> are - should be obvious from client machines using IPCONFIG and
>> TRACERT commands. If problem is only on the router side, then
>> various computers on client side cannot ping each other. That test
>> result also was not reported.
>
> He's using the server as his LAN router. The Netgear router isn't routing
> in the lay sense of the word. That is, in the topography of his network,
> it's not directing traffic here or there. It is only sitting there between
> his server (which is the real router on his LAN), and the cable modem, but
> it's opening packets, and repackaging them as a router does, and not
> simply passing them through as a bridge would.

Correct, with the addition of a Linksys WRT54GL between the LAN switch and
Netgear.


>> Also not defined is whether modem is in router mode or bridge mode.
>
> I can't find a model number for the piece of equipment,

It's a Netgear CG814CCR v2. I'm sorry. I thought I provided this a long
time ago, but I did not.


>but giving this more consideration, I don't think it can actually be
>configured to be a bridge. I believe that it can only act as a router. It
>can act as a NAT router, or it can operate as a normal router. Not normal
>in the same since as a "home" or "broadband" router, which normally acts as
>a NAT router, but normal as in it routes packets to various public IP
>addresses.

This is how I understand it.

>In this case, there's only one IP address to route to, but that doesn't
>mean the equipment stops opening packets like a router does, and turns into
>a bridge that doesn't open packets. (Remember that a router and a bridge
>operate on different levels of the OSI model.)
>
> Also, if it were just a bridge, there's no ISP that's going to waste a
> publicly routable IP address on it. As a bridge, it's IP address would
> only be useful for managing the equipment, and would not be a part of the
> path through the device. For that, they'd use a private range IP address
> just like they do for the cable modem.

That's correct. There is no bridge mode in play here at all. That was a
terminology error on my part.


> The more I think about this issue, assuming that everyone is reporting
> honestly, my confidence that it's not the cable modem, and that the
> failure is happening because something is crashing the router part of the
> Netgear box goes up.

I've been 100% honest, although I can't say for sure I've reported 100% of
the pertinent information. I've done my best, but I've spent a tremendous
amount of time with this issue. If I'm leaving something important out,
it's simple oversight.

As for events since I posted last: Last night I logged into the Linksys and
disabled outbound traffic from the server. I put a 24/7 block on the
server's internet NIC. This morning at 7:50 the Netgear was unresponsive to
ping from my office.

To me, this is compelling information, although I'm not sure how to
interpret it. Does this demonstrate definitively that outbound server
traffic is not the root cause? Did my block indeed prevent all packets from
reaching the Netgear? I seems so. Am I missing something?

Next I want to completely turn the server off for the night. This takes
some doing, because we back up data at night, and I do not have complete
access to the building. But I can arrange it.
Then, depending on the results, I want to disconnect everything from the
Netgear except one clean PC.

I'm not sure what else to try.

Also, what information exactly should I request from Comcast? A text file
containing the router logs?

jm

JM
05-09-07, 10:43 AM
"$Bill" <news@SPAMOLAtodbe.com> wrote in message
news:46416863$0$9902$4c368faf@roadrunner.com...
> w_tom wrote:
>>
>> These are numbers that a tech could provide if he has them. But
>> again, important numbers that might show a problem are still unknown
>> because numbers are not being provided AND what the tech uses to say
>> problem does not exist - both are unknown.
>>
>> There is no acceptable reason why status information is denied the
>> subscriber.
>
> True.

What exactly should I ask for? I will gladly go back to them. When I've
asked for this type of information before they are not sure what to give me.


>> Meanwhile, Warren H's explaination - what the various IP addresses
>> are - should be obvious from client machines using IPCONFIG and
>> TRACERT commands. If problem is only on the router side, then
>> various computers on client side cannot ping each other. That test
>> result also was not reported.
>
> There's a switch in there and another router now, so that shouldn't
> be happening. There may also be a switch on the Netgear ????
> Still don't know the model.

I apologize. It is a Netgear CG814CCR v2

jm

JM
05-09-07, 10:45 AM
"$Bill" <news@SPAMOLAtodbe.com> wrote in message
news:4641a5bd$0$1416$4c368faf@roadrunner.com...
> Warren H wrote:
>> $Bill wrote:
>>
>>> There may also be a switch on the Netgear ????
>>
>>
>> Right. If there's more than one Ethernet port, there would be a switch
>> involved. But a switch operates on an even lower-level than a bridge, so
>> the chances that it's a switch issue is low. And since the most likely
>> switch-related issue would be the physical hardware, since three
>> different Netgear boxes have been used, it's not likely that they all had
>> the same physical defect.
>
> I was referring to the fact that if there is a switch, the packets from
> the LAN may not even make it to the router portion. Therefore, no local
> LAN pinging problem could exist. And we know there's another switch
> farther
> in that should allow the local PCs to ping each other without a router
> getting involved. This in response to Tom's pinging stmt.
>

When the Netgear (model CG814CCR v2) is down (unresponsive, locked up, no
internet, etc), all internal network functions work fine.

jm

Warren H
05-09-07, 07:34 PM
JM wrote:
> As for events since I posted last: Last night I logged into the
> Linksys and disabled outbound traffic from the server. I put a 24/7
> block on the server's internet NIC. This morning at 7:50 the Netgear
> was unresponsive to ping from my office.

I know you don't have any access to configure the modem part of the
Netgear, but do you have any access to configure the router side?

If not, or if unknown, try these ideas: From the customer's side, use a
web browser to access 192.168.100.1, or 192.168.1.1, 192.168.0.1 or
10.1.10.1 the public IP address assigned to the Netgear, or
www.routerlogin.net. If a login/password screen comes up, try cuadmin /
highspeed . I would advise not changing any settings, but rather just
look around. There is probably a "blocked services" (or similar) menu,
and there should be an option for setting a schedule.

If you find that the router has been configured to block services based
on a schedule, any Comcast didn't give you the ability to manage the
router, then call them up, and talk to them again about this situation.
When they've said that the modem doesn't go into sleep mode, they may
not have been thinking about what the router can/can't do, and they may
not have thought about it's ability to block services on a schedule. In
other words, if they were focusing on the modem, they may have
overlooked the anything dealing with the router. On some level they
probably realized it was a combo unit, but they may not have made the
cognitive connection correctly.

If they claim they can't manage the router, ask them to send a tech who
can.

If you are able to look at the router configuration, and you find
there's nothing there that should be a problem, then we've reached a
huge stumbling block. When you shut-down traffic from the server to the
Netgear, that should eliminate the issue of traffic from the LAN
crashing the router. And if Comcast has been honest about the modem logs
indicating that the modem side isn't going down, then we've isolated the
problem to the router side of the Netgear. And since multiple Netgears
have exhibited the same problem, it seems to point towards a
configuration problem on the router side of the Netgear.

BTW... Did you make sure that when they replaced the Netgear they also
replaced the power brick? And have you confirmed that it's not on a
circuit that could be experiencing a surge or brown-out condition during
the time in question? If not, those, and not the configuration, could
still be an issue.

Either way, assuming that Comcast is being truthful about the modem side
not going down, the problem has sufficiently been isolated to the router
side of the Netgear. If they haven't been truthful about the modem
status, then the problem could be further out on their side.

--
Warren H.

==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.

Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker

$Bill
05-09-07, 09:12 PM
JM wrote:
>
> What exactly should I ask for? I will gladly go back to them. When I've
> asked for this type of information before they are not sure what to give me.

If it were me, I'd be asking for a separate cable modem without a router.
Then use your Linksys as the router. There's no logical reason why they
can't provision another modem model. If that works, then I'd ask them
for a separate router too if they're supposed to supply one on a bus. acct.
unless of course you don't mind using your own.

$Bill
05-09-07, 09:18 PM
Warren H wrote:
>
> He's using the server as his LAN router. The Netgear router isn't
> routing in the lay sense of the word. That is, in the topography of his
> network, it's not directing traffic here or there. It is only sitting
> there between his server (which is the real router on his LAN), and the
> cable modem, but it's opening packets, and repackaging them as a router
> does, and not simply passing them through as a bridge would.

I didn't get that from the picture he supplied which I inserted below.
The server isn't even mentioned separately and local routing is basically
uneeded and handled by the switch. Either the Linksys or the Netgear
has to be handling the external routing.

Various computers on the LAN (I assume this includes the server)
V
Network switch
V
Linksys
V
Netgear cable modem/router
V
Comcast headend equipment

GET THE NETGEAR REPLACED WITH A PLAIN OLD MODEM !!!!!

Like a Motorola or Linksys and tell those idiots to provision it and if
they don't know how, have them ask another ISP or Google and find out.

JM
05-10-07, 01:03 PM
"$Bill" <news@SPAMOLAtodbe.com> wrote in message
news:464272f0$0$9934$4c368faf@roadrunner.com...
> Warren H wrote:
>>
>> He's using the server as his LAN router. The Netgear router isn't routing
>> in the lay sense of the word. That is, in the topography of his network,
>> it's not directing traffic here or there. It is only sitting there
>> between his server (which is the real router on his LAN), and the cable
>> modem, but it's opening packets, and repackaging them as a router does,
>> and not simply passing them through as a bridge would.
>
> I didn't get that from the picture he supplied which I inserted below.
> The server isn't even mentioned separately and local routing is basically
> uneeded and handled by the switch. Either the Linksys or the Netgear
> has to be handling the external routing.

The Linksys is handling the "external routing," in terms of your question,
although I think there is a little misunderstanding about this function.
The Netgear is the cable mode, for sure, but it also "routes" our static
public IP address to/from the Linksys, which I have configured for static IP
address, NAT, and no DHCP. DHCP is handled by the Novell server.

Some confusion surrounds exactly what functions are provided by the Netgear,
and I believe our problem is mostly one of semantics and how each of us
thinks of "router" vs "modem." The Netgear is indeed a router, at least in
terms of Comcast's system, but it's not playing that role in terms of the
subscriber network. This has caused great problems for me in my
conversations with Comcast, because my basic view is this:

- a "modem" is a device that converts/reconverts a particular type of
carrier signal to a signal that can be used by computers and networking
equipment
- a "router" is a device that specifies where network traffic goes

So, what is the Netgear doing? In my mind it's being a "modem," not a
"router." However, in Comcast's world it's very much a router. Practically
speaking, Comcast doesn't route internet traffic "to" the subscriber device
(router, switch, NIC, etc) to which their equipment is attached. They route
internet traffic "to" their device, which then "passes to" the subscriber
device.

This is how I understand it. Of course, my understanding of all this is
changing almost by the hour, so don't hesitate to shoot that one full of
holes, too.


> Various computers on the LAN (I assume this includes the server)

Yes.


> GET THE NETGEAR REPLACED WITH A PLAIN OLD MODEM !!!!!

My thoughts and words precisely to at least 2-3 of the Comcast support
people. However, this view reflects a misunderstanding of how Comcast (and
perhaps cable providers in general??) do things. With a business account
using a *static* IP address, there is no such beast as a "plain old modem."
Plain Old Modems are for residential and business accounts with a "dynamic"
IP address.

In the Comcast system, there is no method of assigning a static IP address
to a plain old modem.

And, what's even more frustrating, is that Comcast in my area offers exactly
ONE device for business/static provisioning: The Netgear unit we have.

jm

Warren H
05-10-07, 02:06 PM
JM wrote:
> - a "modem" is a device that converts/reconverts a particular type of
> carrier signal to a signal that can be used by computers and
> networking equipment
> - a "router" is a device that specifies where network traffic goes
>
> So, what is the Netgear doing? In my mind it's being a "modem," not a
> "router."

A modem is a bridge. A bridge is normally used to connect two different
kinds of physical networks. In this case, it is a bridge between the HFC
network, and the Ethernet network. It operates at layer two of the OSI
network. It doesn't open the IP packets; it only changes the physical
medium over which they're carried.

A router can direct traffic to multiple devices, like the lay definition
would infer. But it doesn't have to. A router, in terms of completer
networking, is a device that works on layer three of the OSI model. It
opens the IP packets, and inspects them. Based on that inspection, it
can direct traffic to multiple devices, or it could do a number of other
things.

In it's application here, it is primarily used to segregate the
subscriber's network from the Comcast network. TCP/IP traffic using
private IP addresses cannot travel between networks. Neither can
transport or network protocols that aren't TCP/IP. The primary purpose
of using a router at this point is segregation of networks, not
direction of traffic. Forget the common dictionary definition of what a
route is, or that the device happens to be named a router. Just because
it's named a router doesn't mean it's directing traffic between multiple
devices, and just because it isn't directing traffic between multiple
devices doesn't mean it's not a router in networking terms.



> However, in Comcast's world it's very much a router. Practically
> speaking, Comcast doesn't route internet traffic "to" the subscriber
> device (router, switch, NIC, etc) to which their equipment is
> attached. They route internet traffic "to" their device, which then
> "passes to" the subscriber device.
>
> This is how I understand it. Of course, my understanding of all this
> is changing almost by the hour, so don't hesitate to shoot that one
> full of holes, too.

You're using a layman's concept of what a router is. Remember we're
talking networking here. When I say "router", I'm talking about a device
that works on level 3 of the OSI model, and therefore is partially
opening packets in order to decide what to do with them. I don't care if
there's only one path in and out on each side. That's not relevant in
networking terms.


>> Various computers on the LAN (I assume this includes the
server)
>
> Yes.
>
>
>> GET THE NETGEAR REPLACED WITH A PLAIN OLD MODEM !!!!!
>
> My thoughts and words precisely to at least 2-3 of the Comcast support
> people. However, this view reflects a misunderstanding of how Comcast
> (and perhaps cable providers in general??) do things. With a business
> account using a *static* IP address, there is no such beast as a
> "plain old modem." Plain Old Modems are for residential and business
> accounts with a "dynamic" IP address.
>
> In the Comcast system, there is no method of assigning a static IP
> address to a plain old modem.

It's mostly a business decision to use a combo device. They *can* assign
a static IP address to a customer's equipment with just a modem. The
modem's IP address, a 10.x.x.x address, is only used to manage the
modem, and is not involved in how traffic gets to or through it. Before
DOCSIS, IP wasn't even used to manage the modem, so modems didn't even
have IP addresses. (The exception was the LanCity system, which could
really be thought of as an early version of DOCSIS.)

The apparent reason why they use a combo device for business customers
is that business customers often have more complex networks than home
users, and the router ensures that the two networks are segregated --
and are segregated by a device that the customer can't accidentally take
out of the picture. Essentially, they're afraid that the customer's
complex, mission critical network is going to be operated by someone who
doesn't understand the OSI model, and why it's essential to have a level
3 device segregating the networks.

> And, what's even more frustrating, is that Comcast in my area offers
> exactly ONE device for business/static provisioning: The Netgear unit
> we have.

Then they need to get people who know how to manage it.

When you asked them about a "sleep mode", and they said that there was
no such thing, they were overlooking the ability of the router to block
IP services based on a schedule. Either they were having a cognitive
disconnect, and didn't realize you were talking about the whole device,
and not just the modem part of the combo, or they really don't know what
control they have over their router.

At this point, my confidence that it's the router, not the modem, is
high. You need to be talking to someone who not only knows the box is a
combo device, but understands the difference between the modem and the
router parts, and what they each do. And I'm starting to get the feeling
(based on what you said earlier) that you're not clear about what a
router is as well. Perhaps you don't normally need to know, but whoever
you talk to at Comcast better know, and in this case you need to know so
you can tell whether they know. In other words, someone needs to
understand that a router really does.

(Hint: "A 'router' is a device that specifies where network traffic
goes," as said earlier.)

--
Warren H.

==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.

Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker

$Bill
05-10-07, 02:18 PM
JM wrote:
>
>>GET THE NETGEAR REPLACED WITH A PLAIN OLD MODEM !!!!!
>
>
> My thoughts and words precisely to at least 2-3 of the Comcast support
> people. However, this view reflects a misunderstanding of how Comcast (and
> perhaps cable providers in general??) do things. With a business account
> using a *static* IP address, there is no such beast as a "plain old modem."
> Plain Old Modems are for residential and business accounts with a "dynamic"
> IP address.
>
> In the Comcast system, there is no method of assigning a static IP address
> to a plain old modem.

You're not assigning the IP to the modem, but to the router connected to the
modem. In your case it's all in one Netgear box. Many people have static
IPs to their networks (1 or more) - they just pay a few $/mo for the static
IP(s) and deal with it at the router.

> And, what's even more frustrating, is that Comcast in my area offers exactly
> ONE device for business/static provisioning: The Netgear unit we have.

There's no reason for this. Many ISPs will let you convert from a dynamic IP
to a static IP for $1/mo. It shouldn't make any difference to them what kind
of modem you're using as long as it's on their list of supported devices (and
most ISPs will support several modems). There's something really inept going
on here IMO. It's just a matter of config'ing your router to the static IP.

JM
05-11-07, 01:58 AM
"Warren H" <wholzem@hotmail.com> wrote in message
news:u4KdnYvCLvq4wt7bnZ2dnUVZ_tijnZ2d@comcast.com...
> JM wrote:
>> - a "modem" is a device that converts/reconverts a particular type of
>> carrier signal to a signal that can be used by computers and
>> networking equipment
>> - a "router" is a device that specifies where network traffic goes
>>
>> So, what is the Netgear doing? In my mind it's being a "modem," not a
>> "router."
>
> A modem is a bridge. A bridge is normally used to connect two different
> kinds of physical networks. In this case, it is a bridge between the HFC
> network, and the Ethernet network. It operates at layer two of the OSI
> network. It doesn't open the IP packets; it only changes the physical
> medium over which they're carried.
>
> A router can direct traffic to multiple devices, like the lay definition
> would infer. But it doesn't have to. A router, in terms of completer
> networking, is a device that works on layer three of the OSI model. It
> opens the IP packets, and inspects them. Based on that inspection, it
> can direct traffic to multiple devices, or it could do a number of other
> things.
>
> In it's application here, it is primarily used to segregate the
> subscriber's network from the Comcast network. TCP/IP traffic using
> private IP addresses cannot travel between networks. Neither can
> transport or network protocols that aren't TCP/IP. The primary purpose
> of using a router at this point is segregation of networks, not
> direction of traffic. Forget the common dictionary definition of what a
> route is, or that the device happens to be named a router. Just because
> it's named a router doesn't mean it's directing traffic between multiple
> devices, and just because it isn't directing traffic between multiple
> devices doesn't mean it's not a router in networking terms.
>
>
>
>> However, in Comcast's world it's very much a router. Practically
>> speaking, Comcast doesn't route internet traffic "to" the subscriber
>> device (router, switch, NIC, etc) to which their equipment is
>> attached. They route internet traffic "to" their device, which then
>> "passes to" the subscriber device.
>>
>> This is how I understand it. Of course, my understanding of all this
>> is changing almost by the hour, so don't hesitate to shoot that one
>> full of holes, too.
>
> You're using a layman's concept of what a router is. Remember we're
> talking networking here. When I say "router", I'm talking about a device
> that works on level 3 of the OSI model, and therefore is partially
> opening packets in order to decide what to do with them. I don't care if
> there's only one path in and out on each side. That's not relevant in
> networking terms.
>
>
> >> Various computers on the LAN (I assume this includes the
> server)
>>
>> Yes.
>>
>>
>>> GET THE NETGEAR REPLACED WITH A PLAIN OLD MODEM !!!!!
>>
>> My thoughts and words precisely to at least 2-3 of the Comcast support
>> people. However, this view reflects a misunderstanding of how Comcast
>> (and perhaps cable providers in general??) do things. With a business
>> account using a *static* IP address, there is no such beast as a
>> "plain old modem." Plain Old Modems are for residential and business
>> accounts with a "dynamic" IP address.
>>
>> In the Comcast system, there is no method of assigning a static IP
>> address to a plain old modem.
>
> It's mostly a business decision to use a combo device. They *can* assign
> a static IP address to a customer's equipment with just a modem. The
> modem's IP address, a 10.x.x.x address, is only used to manage the
> modem, and is not involved in how traffic gets to or through it. Before
> DOCSIS, IP wasn't even used to manage the modem, so modems didn't even
> have IP addresses. (The exception was the LanCity system, which could
> really be thought of as an early version of DOCSIS.)
>
> The apparent reason why they use a combo device for business customers
> is that business customers often have more complex networks than home
> users, and the router ensures that the two networks are segregated --
> and are segregated by a device that the customer can't accidentally take
> out of the picture. Essentially, they're afraid that the customer's
> complex, mission critical network is going to be operated by someone who
> doesn't understand the OSI model, and why it's essential to have a level
> 3 device segregating the networks.
>
>> And, what's even more frustrating, is that Comcast in my area offers
>> exactly ONE device for business/static provisioning: The Netgear unit
>> we have.
>
> Then they need to get people who know how to manage it.
>
> When you asked them about a "sleep mode", and they said that there was
> no such thing, they were overlooking the ability of the router to block
> IP services based on a schedule. Either they were having a cognitive
> disconnect, and didn't realize you were talking about the whole device,
> and not just the modem part of the combo, or they really don't know what
> control they have over their router.
>
> At this point, my confidence that it's the router, not the modem, is
> high. You need to be talking to someone who not only knows the box is a
> combo device, but understands the difference between the modem and the
> router parts, and what they each do. And I'm starting to get the feeling
> (based on what you said earlier) that you're not clear about what a
> router is as well. Perhaps you don't normally need to know, but whoever
> you talk to at Comcast better know, and in this case you need to know so
> you can tell whether they know. In other words, someone needs to
> understand that a router really does.
>
> (Hint: "A 'router' is a device that specifies where network traffic goes,"
> as said earlier.)

There's a whole bunch up there that my ego would like to clarify, but it
likely would detract from the target. I do understand what a router does.
I
do understand the OSI model. My attempts to generalize and present the
various miscommunications between myself and a room full of Comcast support
people over the past 4 weeks misrepresented the situation.
That a router operates at layer 3 is a fact. That it does much more than
"route" traffic also is a fact. However, I'm having trouble seeing the
pertinence of this information, in the context of your theory concerning
possible cause. If I'm interpreting your comments correctly, you think the
router might be blocking IP traffic according to a schedule. If that's so,
then would we see the internet "down" specific times of day? Should it be
predictably recurring? Could there be other times of the day when the
internet is intermittent? Finally, would a reset of the Netgear "fix" this
type of problem?

jm

Warren H
05-11-07, 02:50 AM
JM wrote:
> There's a whole bunch up there that my ego would like to clarify, but
> it likely would detract from the target. I do understand what a
> router does. I
> do understand the OSI model. My attempts to generalize and present
> the
> various miscommunications between myself and a room full of Comcast
> support
> people over the past 4 weeks misrepresented the situation.
> That a router operates at layer 3 is a fact. That it does much more
> than
> "route" traffic also is a fact. However, I'm having trouble seeing
> the
> pertinence of this information, in the context of your theory
> concerning possible cause. If I'm interpreting your comments
> correctly, you think the router might be blocking IP traffic according
> to a schedule. If that's so, then would we see the internet "down"
> specific times of day? Should it be predictably recurring? Could
> there be other times of the day when the internet is intermittent?
> Finally, would a reset of the Netgear "fix" this type of problem?


Well, here's where we are:

Comcast has stated that the modem is not going down, and there's nothing
in the modem logs to indicate a problem.

You've isolated your LAN from the Netgear box.

That narrows things down to the router in the Netgear box.

You've implied that this happens every night, over night. That would
seem to indicate a regularly scheduled event.

So possible issues include:
- The router is configured wrong, possibly blocking on a schedule.
- The router has some other problem.
- The router, and the other two also, are all from the same batch,
and are all defective.
- You really didn't isolate your LAN from the Netgear.
- Comcast isn't being honest about the modem not having a problem.

That's a pretty short list, but it could get longer if one of the last
two items on it are where the problem is. But assuming that you did
isolate the LAN from the Netgear box, and assuming that Comcast is
correct that there aren't any problems up to and including the modem
that's in the Netgear box, then we're down to the something with the
router in the Netgear box.

So assuming that isolation troubleshooting has been properly done, and
the results have been correctly reported, it's now time to focus on that
router. I'm suggesting the blocking schedule because the context of your
reports of your conversations with Comcast infer that they aren't aware
of a way that the Netgear box can shut-down sometime overnight, and your
reports on when the problem happens, for the most part, point towards
the same timeframe each day. But that's just one example of what it
could be, and something that I'd look at first in the router
configuration.

My point is that isolation troubleshooting has narrowed us down to the
router. The symptoms reported are not inconsistent with a router
problem. (They were inconsistent with a bridge problem.)

What else can be done?

You can physically disconnect the LAN instead of just disabling the NIC.
That would confirm that you have isolated the problem to someplace
outside your LAN. And Comcast can recheck the modem logs, and recheck
the RF signal to the modem. If everyone re-does, and confirms the steps
they've taken to isolate the problem, then we're right back at the
router. And so far, I've seen absolutely zip on the router
configuration. The only thing we know is that three different physical
routers have been in place during the course of this problem.

Speaking of things I haven't seen addressed, a number of times I've
asked if they only replaced the combo box, or if they also replaced the
power brick for it as well. And I've also asked about what other
electrical equipment might be on the same circuit. Even if you can't get
into the router to check the configuration, you should be able to make
sure that it's getting clean power.

I'm not saying I'm locked into the blocking schedule theory. But I am
saying that if all the information that has been offered is correct, and
all the methodology has been sound, then we have isolated the problem to
that Netgear router packed in the same box as the modem. And despite
replacing the combo box twice already, the problem is still there.

So what else can it be? Either you need to go back and re-do the
isolation troubleshooting again, and see if you wind-up someplace else,
or the problem is in the router. And they symptoms are not inconsistent
with something that can happen with a router.

Where else can we go with this?

--
Warren H.

==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.

Maintain your landscape with Black & Decker:
http://www.holzemville.com/mall/blackanddecker

$Bill
05-11-07, 03:43 AM
Warren H wrote:
>
> Where else can we go with this?

To a tech that can configure something other than a Netgear combo modem. ;)

Eric
05-19-07, 01:04 AM
On May 11, 1:43 am, "$Bill" <n...@SPAMOLAtodbe.com> wrote:
> Warren H wrote:
>
> > Where else can we go with this?
>
> To a tech that can configure something other than a Netgear combo modem. ;)

To a tech that can get a line tech out to set up the amps feeding the
modem.

To a tech that understands that just because a modem is "in spec"
doesn't mean it will work properly.

To a tech that will actually troubleshoot and not just swap out a
perfectly good modem.

JM
05-21-07, 12:21 PM
"Eric" <egrumling@gmail.com> wrote in message
news:1179551066.109815.121600@e65g2000hsc.googlegroups.com...
> On May 11, 1:43 am, "$Bill" <n...@SPAMOLAtodbe.com> wrote:
>> Warren H wrote:
>>
>> > Where else can we go with this?
>>
>> To a tech that can configure something other than a Netgear combo modem.
>> ;)
>
> To a tech that can get a line tech out to set up the amps feeding the
> modem.
>
> To a tech that understands that just because a modem is "in spec"
> doesn't mean it will work properly.
>
> To a tech that will actually troubleshoot and not just swap out a
> perfectly good modem.


I could not agree more. After another week watching this thing go down
every single night and having to reset it every single morning, I'm
convinced there is a signal problem to the modem that could be identified if
a competent tech would perform some real troubleshooting. But the tech they
keep sending does not qualify. In all seriousness, he appears to have a
learning disability. I'm not being mean. I'm just stating the truth. I
feel sorry for him, really, but the fact remains that Comcast is not
bringing high-level resources to bear on this problem.

jm

Eric
05-22-07, 12:36 AM
On May 21, 10:21 am, "JM" <j...@yahoo.com> wrote:
> "Eric" <egruml...@gmail.com> wrote in message
>
> news:1179551066.109815.121600@e65g2000hsc.googlegroups.com...
>
>
>
> > On May 11, 1:43 am, "$Bill" <n...@SPAMOLAtodbe.com> wrote:
> >> Warren H wrote:
>
> >> > Where else can we go with this?
>
> >> To a tech that can configure something other than a Netgear combo modem.
> >> ;)
>
> > To a tech that can get a line tech out to set up the amps feeding the
> > modem.
>
> > To a tech that understands that just because a modem is "in spec"
> > doesn't mean it will work properly.
>
> > To a tech that will actually troubleshoot and not just swap out a
> > perfectly good modem.
>
> I could not agree more. After another week watching this thing go down
> every single night and having to reset it every single morning, I'm
> convinced there is a signal problem to the modem that could be identified if
> a competent tech would perform some real troubleshooting. But the tech they
> keep sending does not qualify. In all seriousness, he appears to have a
> learning disability. I'm not being mean. I'm just stating the truth. I
> feel sorry for him, really, but the fact remains that Comcast is not
> bringing high-level resources to bear on this problem.
>
> jm

You mean they keep sending the same guy? I'm sorry to say this, but
you're going to have to contact your sales rep (since this is a
commercial account, you'll have a sales rep), and demand they escalate
the issue to the local supervisor. It is unacceptable for them to
continue to send the same guy out time and time again without
resolution. Make sure you make your rep aware of all that has
transpired.

JoeSespn
02-16-08, 12:53 PM
I won't go into details about their lack of skill and sending the same person out each time, I do want to spread the information I have from something somewhat similar that may or may not help.

I just got Comcast business, I upgraded from Comcast home. When I first had it installed it was very flaky. I would get intermittent connectivity and speed. VPN, XBox Live, and Vonage were all terribly affected. I troubleshot with their technicians and we determined it was a bad Netgear Cable modem, which they promptly came out and replaced. After it was replaced I still had poor VPN performance (both Cisco VPN, Juniper SSL VPN) as well as poor XBOX live. All of which worked perfectly with Comcast Home internet service. Again I called and worked with their technicians, they verified the firewall on the Netgear was disabled, but it turned out to be Smart Packet Detection on the Netgear which was causing all the problems. They shut off Smart Packet Detection and everything has worked perfectly since. Maybe you can call them and ask about that.

The symptoms I saw with this were most clear with Ethereal, showing severe packet loss (retries galore) when VPN'd, but clean as a whistle when not VPN'd.

Again, not sure if this is totally related as your symptoms seem to be time related, but perhaps there is a scheduled *something* that is triggering the Smart Packet Detection.

bojack13
04-13-08, 03:52 PM
Sorry to bring up this old topic. Are any of the original posters still around? It was an interesting read and I'd like to know if a solution was ever found.