nanog mailing list archives
Re: Smallest Transit MTU
From: Dan Hollis <goemon () anime net>
Date: Wed, 29 Dec 2004 15:39:28 -0800 (PST)
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
Current thread:
- Re: Smallest Transit MTU, (continued)
- Re: Smallest Transit MTU Daniel Hagerty (Dec 29)
- Re: Smallest Transit MTU Alex Bligh (Dec 29)
- Re: Smallest Transit MTU Joe Abley (Dec 29)
- Re: Smallest Transit MTU Tony Rall (Dec 29)
- Re: Smallest Transit MTU Iljitsch van Beijnum (Dec 29)
- Re: Smallest Transit MTU Joe Abley (Dec 29)
- Re: Smallest Transit MTU Iljitsch van Beijnum (Dec 29)
- Re: Smallest Transit MTU Edward B. Dreger (Dec 29)
- Re: Smallest Transit MTU Robert E . Seastrom (Dec 30)
- Re: Smallest Transit MTU John Kristoff (Dec 30)
- RE: Smallest Transit MTU David Schwartz (Dec 30)
- Re: Smallest Transit MTU John Kristoff (Dec 30)
- RE: Smallest Transit MTU David Schwartz (Dec 30)
- Re: Smallest Transit MTU Robert E . Seastrom (Dec 30)
- Re: Smallest Transit MTU John Kristoff (Dec 30)
- Re: Smallest Transit MTU Robert E . Seastrom (Dec 31)