PMTU and Broken Servers

Niels Bakker niels=nanog at
Tue May 13 09:48:22 UTC 2003

* stephen at (Stephen Sprunk) [Mon 12 May 2003, 19:24 CEST]:
> Most network folk have found it's easier to provide 1500 MTU than to
> educate all of the server operators and end users as to what's going
> wrong with PMTU.  This is also, IMHO, the only significant reason jumbo
> frames aren't in widespread use -- we have no reliable means of coping
> with networks that remain at 1500 MTU.

That was already the case when the FDDI MAEs were still in operation
with their 4470 byte MTUs, where the Gigaswitches didn't have IP
addresses they could send ICMP Fragmentation Needed messages from
when having to bridge large frames from FDDI to Ethernet...


	-- Niels.

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