[40832] in North American Network Operators' Group
Re: Ethernet NAPs (was Re: Miami ...)
daemon@ATHENA.MIT.EDU (Greg Maxwell)
Thu Aug 23 11:43:53 2001
Date: Thu, 23 Aug 2001 11:37:09 -0400 (EDT)
From: Greg Maxwell <gmaxwell@martin.fl.us>
To: <jtk@aharp.is-net.depaul.edu>
Cc: Nanog <nanog@merit.edu>
In-Reply-To: <3B8510A1.B596C9B5@depaul.edu>
Message-ID: <Pine.GSO.4.33.0108231135000.11469-100000@da1server.martin.fl.us>
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On Thu, 23 Aug 2001, John Kristoff wrote:
>
> Mikael Abrahamsson wrote:
> > If NAPs do not support jumbos, then end systems will never support them.
>
> Many end systems will never support jumbo frames, period. There are
> lots of 10/100 Mb/s ethernet hosts that will not ever be upgraded.
While not a standard feature, many 100mbit nics support jumbo on
full-duplex links and some 100tx switches do as well.
> Certainly. In a nutshell, it might be best to take steps to avoid
> fragmentation elsewhere in the network. Perhaps a rule of thumb that
> should be stressed is to use jumbo frames if you know for sure the other
> end system(s) support it, otherwise default to 1500.
Path MTU discovery works fine. (except for broken firewalls) Your
complaint about end systems never supporting jumbos is a moot point
because if neither end supports them, then PMTU discovery isn't even an
issue.
