On Wed, 29 Dec 2004, Florian Weimer wrote: > * Dan Hollis: > > On Wed, 29 Dec 2004, Jerry Pasker wrote: > >> Is there an RFC that clearly states: "The internet needs to transit > >> 1500 byte packets without fragmentation."?? > > Actually the bigger problem imo is the number of sites which block ECN > > http://urchin.earth.li/ecn/ > Why is this a problem? ECN has to be deployed on routers, and it > currently isn't.
Because tcp connection endpoints have to implement ECN in order to manage the flow. Many OSes (Linux/bsd/aix/solaris/etc) support ECN but due to the large number of braindamaged firewalls out there (http://urchin.earth.li/ecn/), it defaults to off. Any host which tries to negotiate ECN in a tcp connection will run into lots of problems as millions of idiotic firewalls drop the packets on the floor. Quite often the same firewalls which drop 69/8 on the floor. Its sad because ECN is quite useful. Though the damage by clueless network admins blocking 69/8 is worse. > Cisco seems to offer it on some platforms, but their implementation > provides a strong incentive to constantly set the ECN flags in a > certain way, to push the packets into a different QoS class. > (This is from memory, and it might have been corrected.) http://www.icir.org/floyd/ecn.html -Dan
