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From: vjs@rhyolite.wpd.sgi.com (Vernon Schryver)
Newsgroups: comp.dcom.lans
Subject: Re: 10Base-T hubs
Summary: old diatribe about FDDI<->ethernet bridges
Message-ID: <98626@sgi.sgi.com>
Date: 21 Apr 91 19:32:54 GMT
References: <1991Apr16.182217.6151@netcom.COM> <1991Apr17.212748.7165@shl.com> <1991Apr21.021222.947@engin.umich.edu>
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Be careful about enthusiasm for FDDI<-->ethernet bridges.  One hint of the
problems is that they stopped being called "transparent" and started being
called "translucent bridges" in about 1989.  An example of the problems can
been seen by considering the implications of putting half of an NFS
client/server pair the fiber and the other half on ethernet--the "bridge"
must fragment UDP/IP packets to make things work.

Also beware that some early FDDI bridges did not use RFC-1103, and so can
talk only to each other.  They "tunnelled" ethernet thru FDDI, instead of
bridging between ethernet and FDDI.



Vernon Schryver,  vjs@sgi.com