Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!asuvax!ncar!csn!boulder!daemon
From: fin@unet.unet.umn.edu (Craig A. Finseth)
Newsgroups: comp.dcom.sys.cisco
Subject: cisco's FDDI MTU vs. RFC1188
Message-ID: <35321@boulder.Colorado.EDU>
Date: 23 May 91 04:41:07 GMT
Sender: daemon@boulder.Colorado.EDU
Lines: 18


	...
   The RFC reserves some space for "expanding the MAC header" (what a bad
   idea (expanding it, not reseving the space)).  The cisco implementation
   pre-dates RFC1188, and is based on RFC1103, which specifies 4470.
	...

Actually, this is not a bad idea.  For example, the 802.10 (secure
LANs) standard specifies additional header information by necessity.
This extra buffer prevents fragmented Ethernet packets, which are a
much worse problem than losing a tiny percentage of an FDDI packet,
the vast majority of which will be either 576 or 1536 bytes anyways.

Craig A. Finseth			fin@unet.umn.edu [CAF13]
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