> I may have misunderstood you. Ddi you have 8936 configured on both > ends? I thought you had only 8936 on the CSR. > > How I understood it: > > *Dec 8 11:17:15.453: TCP0: Connection to 12.0.0.7:179, advertising MSS 8936 > *Dec 8 11:17:15.456: TCP: tcb 7FFB9A6D64C0 connection to > 12.0.0.7:179, peer MSS 1240, MSS is 1240 > > Local 12.0.0.13 CSR is advertising 8936 to remote 12.0.0.7 > Remote 12.0.0.7 is advertising 1240 > We settle to 1240
> I guess you are saying the remote 12.0.0.7 is as well configured to > 8936? Exactly. This is the configuration I have on 12.0.0.7: neighbor 12.0.0.13 remote-as 12 tcp mss 8936 update-source Loopback0 address-family vpnv4 unicast ! address-family ipv4 rt-filter ! address-family l2vpn evpn So my understanding *was* that this command is enforcing MSS=8936, no matter if it's SYN or SYN ACK. > Then I agree, I wouldn't expect that, and can't explain it. > Almost sounds like a bug where the configuration command is only read > when IOS-XR establishes the connection, but not when it receives it? That's my thought as well. But this is strange as I have 7.5.2 and 6.7.3 in the lab and the behavior is the same. I guess it's time to ask TAC friends :) Thanks! Kind regards, Marcin czw., 8 gru 2022 o 10:50 Saku Ytti <s...@ytti.fi> napisaĆ(a): > On Thu, 8 Dec 2022 at 11:40, Marcin Kurek <md.ku...@gmail.com> wrote: > > > > > https://www.rfc-editor.org/rfc/rfc8654.html > > > > Thanks! > > > > > But it was [8936, 1240].min - so it was 'negotiated' here to the > > > smallest? If you change the 8936 end to 1239, then that will be used, > > > regardless who starts it. > > > > Yes, but why would XR advertise 1240 if I'm using 'tcp mss 8936' for > that neighbor? > > Initially I thought that the whole point of this command is to set MSS > to a fixed value of our choice. > > I may have misunderstood you. Ddi you have 8936 configured on both > ends? I thought you had only 8936 on the CSR. > > How I understood it: > > *Dec 8 11:17:15.453: TCP0: Connection to 12.0.0.7:179, advertising MSS > 8936 > *Dec 8 11:17:15.456: TCP: tcb 7FFB9A6D64C0 connection to > 12.0.0.7:179, peer MSS 1240, MSS is 1240 > > Local 12.0.0.13 CSR is advertising 8936 to remote 12.0.0.7 > Remote 12.0.0.7 is advertising 1240 > We settle to 1240 > > I guess you are saying the remote 12.0.0.7 is as well configured to > 8936? Then I agree, I wouldn't expect that, and can't explain it. > Almost sounds like a bug where the configuration command is only read > when IOS-XR establishes the connection, but not when it receives it? > > -- > ++ytti > _______________________________________________ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/