nanog mailing list archives
Re: PPPOE, MTU, and boom.
From: Alex Rubenstein <alex () nac net>
Date: Thu, 19 Jul 2001 01:11:41 -0400 (Eastern Daylight Time)
This section describes possibly unexpected behavior that are resolved in Release 12.2(2)XH. CSCds69577 Starting with Release 12.2(2)XH, you can resolve this problem by changing the value of the maximum segment size (MSS) contained in the MTU to 1492 or less. Use the following IOS command: ip tcp adjust-mss mss where mss is 1492 or less.
Post-mortem: this seems to work. Hoever, mss is 1460 or less, assuming mtu is 1492. dsl1.ahr(config-if)#ip tcp adjust-mss ? <500-1460> Maximum segment size in bytes Key (which took me a moment to figure out): the mss MUST be AT LEAST 32 bytes or more less than MTU; for a while, I had MTU set to 1400 on the aggregation side, and didn't realise it, and this didn't work. As soon as I upped the MTU to 1492, all started working, including all broken sites and quicken.
Current thread:
- Re: PPPOE, MTU, and boom., (continued)
- Re: PPPOE, MTU, and boom. Alex Rubenstein (Jul 18)
- Re: PPPOE, MTU, and boom. Jamie Bowden (Jul 18)
- Re: PPPOE, MTU, and boom. Alex Rubenstein (Jul 18)
- Re: PPPOE, MTU, and boom. Charles Sprickman (Jul 18)
- Re: PPPOE, MTU, and boom. Robert Boyle (Jul 18)
- Re: PPPOE, MTU, and boom. Alex Pilosov (Jul 18)
- Re: PPPOE, MTU, and boom. Jeff Mcadams (Jul 18)
- Re: PPPOE, MTU, and boom. Miquel van Smoorenburg (Jul 18)
- Re: PPPOE, MTU, and boom. Alex Rubenstein (Jul 18)
- Re: PPPOE, MTU, and boom. Alex Rubenstein (Jul 18)