Re: exchange point media (was: Re: MAE-EAST Moving? ...)

[John Hall <j.hall () f5 com>]

This is a problem for many switches that support non-ethernet interfaces.
RFC1191 does not apply to switches (only routers), but it probably should.
I've run into this problem with switches from Fore and Cabletron.  I would
bet that this is a problem for most switches.

JMH

Jeff Haas wrote:
...
> Should one install a (fast|gig)ethernet card into one's Gigaswitch
> and said switch have FDDI interfaces, the switch will go from having
> a 4500+ byte MTU to a 1500 byte MTU.  This is even between FDDI card
> to FDDI card on the same switch.
>
> The switch will happily fragment the packet if you leave DF off.
> However, if you turn it on, the switch will drop the packet silently.
> The switch is unable to generate ICMP and route it back to the
> sender.
>
> Given all of this, PMTU-D breaks in these circumstances.
...
> --
> Jeffrey Haas - Merit RSng project - jeffhaas () merit edu

-- 
John Hall <j.hall () f5 com>                                     F5 Networks, Inc.
Senior Test Engineer                                          206-505-0800

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