nanog mailing list archives
RE: Thoughts on increasing MTUs on the internet
From: "Lasher, Donn" <DLasher () newedgenetworks com>
Date: Fri, 13 Apr 2007 12:18:34 -0700
-----Original Message----- From: owner-nanog () merit edu [mailto:owner-nanog () merit edu] On Behalf Of Stephen Sprunk Sent: Friday, April 13, 2007 10:32 AM To: Mikael Abrahamsson Cc: North American Noise and Off-topic Gripes Subject: Re: Thoughts on increasing MTUs on the internet
PMTU Black Hole Detection works well in my experience, but unfortunately MS
doesn't turn it on by default, which is
where all of the L2VPN with <1500 MTU issues come from; turn BHD on and
the problems just go away... (And, as others
have noted, there's better PMTUD algorithms that are designed to work
_with_ black holes, but IME they're not really
needed)
I wish I'd had your experience. PMTU _can_ work well, but on the internet as a whole, far too many ignorant paranoid admins block PMTU, mostly by accident, causing all sorts of unpleasantness. Clearing DF only takes you so far. Unless both ends are aware, and respond apppropriately to the squeeze in the middle, you're back to square one. Unless there were some other method of MTU Discovery implemented, depending on something like PMTU discovery may fail just as dramatically on larger packets as it does on 1500byte now.
Attachment:
smime.p7s
Description:
Current thread:
- Re: Thoughts on increasing MTUs on the internet, (continued)
- Re: Thoughts on increasing MTUs on the internet Randy Bush (Apr 12)
- RE: Thoughts on increasing MTUs on the internet Buhrmaster, Gary (Apr 12)
- Re: Thoughts on increasing MTUs on the internet Randy Bush (Apr 12)
- Re: Thoughts on increasing MTUs on the internet Randy Bush (Apr 12)
- Re: Thoughts on increasing MTUs on the internet Stephen Satchell (Apr 12)
- Re: Thoughts on increasing MTUs on the internet Saku Ytti (Apr 12)
- Re: Thoughts on increasing MTUs on the internet Valdis . Kletnieks (Apr 13)
- RE: Thoughts on increasing MTUs on the internet Leigh Porter (Apr 13)
- RE: Thoughts on increasing MTUs on the internet Mikael Abrahamsson (Apr 13)
- Re: Thoughts on increasing MTUs on the internet Stephen Sprunk (Apr 13)
- RE: Thoughts on increasing MTUs on the internet Lasher, Donn (Apr 13)
- Re: Thoughts on increasing MTUs on the internet Stephen Sprunk (Apr 13)
- Re: Thoughts on increasing MTUs on the internet Steve Meuse (Apr 13)
- Re: Thoughts on increasing MTUs on the internet Adrian Chadd (Apr 13)
- RE: Thoughts on increasing MTUs on the internet michael.dillon (Apr 13)
- Re: Thoughts on increasing MTUs on the internet Stephen Wilcox (Apr 12)
- Re: Thoughts on increasing MTUs on the internet Joe Loiacono (Apr 12)
- Re: Thoughts on increasing MTUs on the internet Mikael Abrahamsson (Apr 12)
- Re: Thoughts on increasing MTUs on the internet Joe Loiacono (Apr 12)
- Re: Thoughts on increasing MTUs on the internet Mikael Abrahamsson (Apr 12)