TCP Analyser

Dale-C · Post by **Dale-C** » Tue Dec 22, 2009 9:51 am

Hey guys the TCP Analyser reckons my MTU is 1460. I have changed the router to 1500 then back to 1492 again and the Analyser reckons its still 1460. I have changed ell the settings in my registry with the guide and even use the Vista Tweaker. You guys know whats goin on?

« SpeedGuide.net TCP Analyzer Results »
Tested on: 12.22.2009 09:47
IP address: 121.45.xxx.xxx
Client OS: Windows Vista

TCP options string: 0204058c0103030201010402
MSS: 1420
MTU: 1460
TCP Window: 66740 (multiple of MSS)
RWIN Scaling: 2 bits (2^2=4)
Unscaled RWIN : 16685
Recommended RWINs: 65320, 130640, 261280, 522560, 1045120
BDP limit (200ms): 2670kbps (334KBytes/s)
BDP limit (500ms): 1068kbps (133KBytes/s)
MTU Discovery: ON
TTL: 43
Timestamps: OFF
SACKs: ON
IP ToS: 00000000 (0)

Dale.

trogers · Post by **trogers** » Tue Dec 22, 2009 12:39 pm

Dale-C wrote:Hey guys the TCP Analyser reckons my MTU is 1460. I have changed the router to 1500 then back to 1492 again

If there is a setting for MSS, it will need to be set to 1460 (for MTU at 1500) and 1452 (for MTU at 1492), 'else MSS will override MTU settings.

Dale-C · Post by **Dale-C** » Wed Dec 23, 2009 4:02 am

I'm pretty sure ther isn't an MSS on the router, I didn't think many routers had it either. And why would my MSS be 1420 Anyway? The router is a Netgear DG834Gv2 With 849DGTeam Firmware

trogers · Post by **trogers** » Wed Dec 23, 2009 4:58 am

Dale-C wrote:I'm pretty sure ther isn't an MSS on the router, I didn't think many routers had it either. And why would my MSS be 1420 Anyway? The router is a Netgear DG834Gv2 With 849DGTeam Firmware

Your router has vpn function and MTU will be sized down to allow vpn to work. Some netgear router may even require MTU to be as low as 1398:

http://forums.techguy.org/networking/39 ... lives.html

Dale-C · Post by **Dale-C** » Mon Dec 28, 2009 4:52 am

I have no entries in my VPN and I have disabled it.

I just did the ping -f -l thing and got max: ping -f -l 1464 to on.net
So does that mean I have to change my Router and PC to 1464?

trogers · Post by **trogers** » Mon Dec 28, 2009 9:42 am

Dale-C wrote:I have no entries in my VPN and I have disabled it.

I just did the ping -f -l thing and got max: ping -f -l 1464 to on.net
So does that mean I have to change my Router and PC to 1464?

MTU = max ping + 28 = 1492.

This is the MTU for PPPoE ADSL internet service.

Dale-C · Post by **Dale-C** » Mon Dec 28, 2009 11:27 pm

So I don't need to change anything?

trogers · Post by **trogers** » Mon Dec 28, 2009 11:38 pm

Dale-C wrote:So I don't need to change anything?

If the Analyzer is still reporting MTU at 1460, then MTU is changed as signal passes through the router.

If so, your may need to check for an updated firmware for the router.

Dale-C · Post by **Dale-C** » Thu Jan 07, 2010 4:27 pm

I have tried all firmwares and still 1460 with my MTU set at 1492 on my router.

Will PPPoA Make any difference? And should I set the encapsulation to VC Based instead of LLC Based for PPPoE?