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Thread: Router vs. Telco DSL Quality Stats

  1. #1
    Jon.R.Kibler@gmail.com
    Guest

    Router vs. Telco DSL Quality Stats

    Hi,

    We have been having an on-going battle with several local telcos over
    DSL line quality. For some reason their testers always show a much
    higher line quality than does the routers.

    For example, I have taken the exact same DSL POTS cable, and plugged
    it into a Cisco 827, 837, and 877 router and got essentially the same
    line quality stats. When the local telco test the line (usually using
    a SunSet MTT test set), they consistently see a good quality line,
    where the routers see a marginal line -- one that keeps dropping. (And
    this is not just a single line at a single location -- we have the
    same problem at multiple locations, and at some locations, on multiple
    lines at that location.)

    For example, here is what the router reports:
    ATU-R (DS) ATU-C (US)
    Capacity Used: 98% 53%
    Noise Margin: 5.0 dB 12.0 dB
    Output Power: 17.0 dBm 8.0 dBm
    Attenuation: 64.0 dB 31.5 dB
    Interleave Fast
    Interleave Fast
    Speed (kbps): 1216 0
    256 0

    and the test set reports:

    Capacity: 47% / 40%
    SNR: 8.5dB / 15dB
    Attenuation: 40dB / 28dB
    kbps: 1472 / 256 (noise profile)

    Why such a substantial disagreement between telco test sets and Cisco
    routers? Especially when there is no difference between the wiring to
    the device, up to and including the cable plugged into the device.

    This is getting to be a real pain. We have flaky connections and
    numerous drops, yet the telco says everything is fantastic. It just
    doesn't make sense.

    TIA for any insights into this problem.

    Jon K.

  2. #2
    LouB
    Guest

    Re: Router vs. Telco DSL Quality Stats

    Jon.R.Kibler@gmail.com wrote:
    > Hi,
    >
    > We have been having an on-going battle with several local telcos over
    > DSL line quality. For some reason their testers always show a much
    > higher line quality than does the routers.
    >
    > For example, I have taken the exact same DSL POTS cable, and plugged
    > it into a Cisco 827, 837, and 877 router and got essentially the same
    > line quality stats. When the local telco test the line (usually using
    > a SunSet MTT test set), they consistently see a good quality line,
    > where the routers see a marginal line -- one that keeps dropping. (And
    > this is not just a single line at a single location -- we have the
    > same problem at multiple locations, and at some locations, on multiple
    > lines at that location.)
    >
    > For example, here is what the router reports:
    > ATU-R (DS) ATU-C (US)
    > Capacity Used: 98% 53%
    > Noise Margin: 5.0 dB 12.0 dB
    > Output Power: 17.0 dBm 8.0 dBm
    > Attenuation: 64.0 dB 31.5 dB
    > Interleave Fast
    > Interleave Fast
    > Speed (kbps): 1216 0
    > 256 0
    >
    > and the test set reports:
    >
    > Capacity: 47% / 40%
    > SNR: 8.5dB / 15dB
    > Attenuation: 40dB / 28dB
    > kbps: 1472 / 256 (noise profile)
    >
    > Why such a substantial disagreement between telco test sets and Cisco
    > routers? Especially when there is no difference between the wiring to
    > the device, up to and including the cable plugged into the device.
    >
    > This is getting to be a real pain. We have flaky connections and
    > numerous drops, yet the telco says everything is fantastic. It just
    > doesn't make sense.
    >
    > TIA for any insights into this problem.
    >
    > Jon K.


    The telcos are lying to save money. Escalate the complaint.

  3. #3
    Merv
    Guest

    Re: Router vs. Telco DSL Quality Stats


    you should check that you have the latest DSL firmware loaded

    see Cisco doc "IOS Software Release-to-DSL Firmware Version Mapping on
    Cisco Access Routers"

    http://www.cisco.com/en/US/prod/coll...d801d5c4c.html


  4. #4
    Bod43@hotmail.co.uk
    Guest

    Re: Router vs. Telco DSL Quality Stats

    On 3 Apr, 10:12, Merv <merv.hr...@rogers.com> wrote:
    > you should check that you have the latest DSL firmware loaded
    >
    > see Cisco doc "IOS Software Release-to-DSL Firmware Version Mapping on
    > Cisco Access Routers"
    >
    > http://www.cisco.com/en/US/prod/coll...1/prod_bulleti...


    There are free ftp downloads of firmware for the 8[57]7.
    ftp://ftp.cisco.com/pub/access/800

    I have found them to be useful in a number of cases but since the
    IOS bundled firmware went to 3.x I have not bothered.

    Certainly with the 857 and 877 I have seen numerous issues
    that firmware changes have resolved.

    This has been in the UK.

  5. #5
    Jon.R.Kibler@gmail.com
    Guest

    Re: Router vs. Telco DSL Quality Stats

    Thanks to all. I will try some firmware upgrades this weekend.

    I guess that leaves me with the question of how the firmware can
    effect apparent line quality? It seems that line quality should be
    independent of the chipset/firmware used. Can someone please explain
    this?

    Again, THANKS!

    Jon Kibler

  6. #6
    Hans =?iso-8859-1?Q?J=F8rgen?= Jakobsen
    Guest

    Re: Router vs. Telco DSL Quality Stats

    On Thu, 3 Apr 2008 08:13:13 -0700 (PDT), Jon.R.Kibler@gmail.com wrote:
    > Thanks to all. I will try some firmware upgrades this weekend.
    >
    > I guess that leaves me with the question of how the firmware can
    > effect apparent line quality? It seems that line quality should be
    > independent of the chipset/firmware used. Can someone please explain
    > this?


    If your DSL vendor has a list of recomended modems follow that or
    you are on your own!

    Not all combinations chipset/firmware work equaly well.

    When my local telco do a full test they are testing at all cable
    lengths in 50meter(150feet) incriments. And they have found "funny"
    bugs.
    /hjj

  7. #7
    Who Me?
    Guest

    Re: Router vs. Telco DSL Quality Stats


    <Jon.R.Kibler@gmail.com> wrote

    > I guess that leaves me with the question of how the firmware can
    > effect apparent line quality? It seems that line quality should be
    > independent of the chipset/firmware used. Can someone please explain
    > this?
    >


    If we forget for the moment that the term "line quality" is itself somewhat
    ambiguous...........

    The chipset/firmware may not be capable of making full use of a "good" line.
    Or there may be "glitches" in the good line.
    Or the equipment at your end might not be fully compatible with what the ISP
    has at his end.
    Or the equipment at your end might just be "bad".

    Not too complicated really.

    And to echo a previous post: If you insist on using equipment that is not on
    your ISPs approved list, then you're on your own.......and it doesn't sound
    like you are qualified to take up that challenge.




  8. #8
    Franc Zabkar
    Guest

    Re: Router vs. Telco DSL Quality Stats

    On Wed, 2 Apr 2008 11:30:16 -0700 (PDT), Jon.R.Kibler@gmail.com put
    finger to keyboard and composed:

    >Hi,
    >
    >We have been having an on-going battle with several local telcos over
    >DSL line quality. For some reason their testers always show a much
    >higher line quality than does the routers.
    >
    >For example, I have taken the exact same DSL POTS cable, and plugged
    >it into a Cisco 827, 837, and 877 router and got essentially the same
    >line quality stats. When the local telco test the line (usually using
    >a SunSet MTT test set), they consistently see a good quality line,
    >where the routers see a marginal line -- one that keeps dropping. (And
    >this is not just a single line at a single location -- we have the
    >same problem at multiple locations, and at some locations, on multiple
    >lines at that location.)
    >
    >For example, here is what the router reports:
    > ATU-R (DS) ATU-C (US)
    >Capacity Used: 98% 53%
    >Noise Margin: 5.0 dB 12.0 dB
    >Output Power: 17.0 dBm 8.0 dBm
    >Attenuation: 64.0 dB 31.5 dB
    > Interleave Fast
    >Interleave Fast
    >Speed (kbps): 1216 0
    >256 0
    >
    >and the test set reports:
    >
    >Capacity: 47% / 40%
    >SNR: 8.5dB / 15dB
    >Attenuation: 40dB / 28dB
    >kbps: 1472 / 256 (noise profile)
    >
    >Why such a substantial disagreement between telco test sets and Cisco
    >routers? Especially when there is no difference between the wiring to
    >the device, up to and including the cable plugged into the device.
    >
    >This is getting to be a real pain. We have flaky connections and
    >numerous drops, yet the telco says everything is fantastic. It just
    >doesn't make sense.
    >
    >TIA for any insights into this problem.
    >
    >Jon K.


    Apart from the downstream attentuation, it seems that your two sets of
    readings are within agreement, there being a consistent 3.5dB
    difference which I suspect may reflect different refence points (?).
    The big 64dB versus 40dB discrepancy is a worry, though. Could there
    be a 24dB loss within your premises? (but wouldn't that affect the
    output power also???)

    FWIW, here is my ISP's explanation as to factors that may affect
    performance:
    http://www.internode.on.net/resident...ernet/extreme/

    There is also a "how fast can it be?" graph that charts speed versus
    attenuation.

    - Franc Zabkar
    --
    Please remove one 'i' from my address when replying by email.

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