On 6 mei 2008, at 23:48, [EMAIL PROTECTED] wrote: >> A more common approach is to rewrite the MSS option in all TCP SYNs >> with a smaller value so there won't be TCP segments large enough to >> trigger the problem. AFAIK, all boxes that do PPPoE do this.
> And just the other day, you were saying: >> Very few people out there use an MTU significantly below 1500 >> bytes. A >> 1500-byte MTU will give you an _average_ packet size of ~1000 on >> long- >> lived TCP flows because there is one tiny ACK for every two full size >> data segments. Right. Why is that noteworthy? I have a lot more to say about MTU issues in this draft about negotating MTUs between two hosts/routers on a subnet so jumboframes can be deployed without manual configuration: http://www.ietf.org/internet-drafts/draft-van-beijnum-multi-mtu-02.txt > Apparently, there's a *reason* why RFC1122, section 3.3.3 says: > It is generally desirable to avoid local fragmentation and to > choose EMTU_S low enough to avoid fragmentation in any gateway > along the path. In the absence of actual knowledge of the > minimum MTU along the path, the IP layer SHOULD use > EMTU_S <= 576 whenever the destination address is not on a > connected network, and otherwise use the connected network's > MTU. Tell it to Microsoft and their ICMP-filtering friends... _______________________________________________ NANOG mailing list NANOG@nanog.org http://mailman.nanog.org/mailman/listinfo/nanog
