MTU setting in Linksys Router

[Doh! Nutz]

Hello All,

I'm new to the group, tried the tweaks and am happy aside from my MTU setting. In Win98, I'm all set to 1500, however after running TCP analyzer, it says my Linksys router may be limiting the MTU to 1476.

Do you know if there's any way to get the router to an MTU of 1500? Probly not huh...

Am on @home. Just got up and running today.

Thanx ahead, for any advice!


TCP options string = 0204059c0103030401010402
MTU = 1476
MTU is not fully optimized for broadband. Consider increasing your MTU to 1500 for better throughput. If you are using a router, it could be
limiting your MTU regardless of Registry settings.
MSS = 1436
Maximum useful data in each packet = 1436, which is equal to MSS.
MSS is not fully optimized for broad band (although it might work well for slower connections). Consider increasing your MTU value.
Default Receive Window (RWIN) = 642240
RWIN Scaling (RFC1323) = 4 bits
Unscaled Receive Window = 40140
For optimum performance, consider changing RWIN to a multiple of MSS.
Other values for RWIN that might work well with your current MTU/MSS:
505472 (MSS x 44 * scale factor of 8)
252736 (MSS x 44 * scale factor of 4)
126368 (MSS x 44 * scale factor of 2)
63184 (MSS x 44)
bandwidth * delay product:
Your RcvWindow limits you to: 25689.6 kbps (3211.2 KBytes/s) @ 200ms
Your RcvWindow limits you to: 10275.84 kbps (1284.48 KBytes/s) @ 500ms
MTU Discovery (RFC1191) = ON
Time to live left = 56 hops
TTL value is ok.
Timestamps (RFC1323) = OFF
Selective Acknowledgements (RFC2018) = ON
IP type of service field (RFC1349)= 00000000

[Lobo]

First off your RWIN is way to large for your systen and what version of firmware are you using, and do you have Cablenuts adjuster:) :)

[Doh! Nutz]

Ok... What rwin would you suggest? I am definitely open to your advice. As far as firmware, I'm on version 1.37, Jan 03 2001, and no...I don't have cablenutz adjuster. Never heard of it! I'd be glad to check it out tho

[Doh! Nutz]

Dropped the RWIN down to 505472.

Here's the results

TCP options string = 0204059c0103030301010402
MTU = 1476
MTU is not fully optimized for broadband. Consider increasing your MTU to 1500 for better throughput. If you are using a router, it could be
limiting your MTU regardless of Registry settings.
MSS = 1436
Maximum useful data in each packet = 1436, which is equal to MSS.
MSS is not fully optimized for broad band (although it might work well for slower connections). Consider increasing your MTU value.
Default Receive Window (RWIN) = 505472
RWIN Scaling (RFC1323) = 3 bits
Unscaled Receive Window = 63184
RWIN is a multiple of MSS
Other values for RWIN that might work well with your current MTU/MSS:
252736 (MSS x 44 * scale factor of 4)
126368 (MSS x 44 * scale factor of 2)
63184 (MSS x 44)
bandwidth * delay product:
Your RcvWindow limits you to: 20218.88 kbps (2527.36 KBytes/s) @ 200ms
Your RcvWindow limits you to: 8087.552 kbps (1010.944 KBytes/s) @ 500ms
MTU Discovery (RFC1191) = ON
Time to live left = 56 hops
TTL value is ok.
Timestamps (RFC1323) = OFF
Selective Acknowledgements (RFC2018) = ON
IP type of service field (RFC1349)= 00000000

[Lobo]

OK, First go to help page below in signature and follow the instructions, after you install Cablenut, and our patches, try RWIN's of 64240, 385440, 405880, 417560 or 420480
Lasted Linksy's firmware, you need 1.39 hare (http://www.practicallynetworked.com/support/linksys_router_help_pg2.htm)


When you change RWIN in adjuster inside 4.2 on your desktop, save to registry everytime and reboot, check analyzer here to make sure RWIN is in :) :)

[Doh! Nutz]

Great Lobo! Thanx for the help. will get back in a bit.