Inter-exchange media types

Mike O'Dell mo at uunet.uu.net
Sat May 4 12:23:11 UTC 1996


Before you count-out switched FDDI, note that there are other FDDI
switches in the world these days (with all deference to the Gigaswith's
pioneering efforts, in whose hands our butts are held).  They look to
have good performance and the cost-per-port is rather lower.  (Getting
to be second and third, etc, is often a considerable advantage.)

It's too bad there isn't an "official" way to run larger MTU (eg, FDDI)
with 100baseTX running point-to-point Full-Duplex.  Some of the chips
even have control bits ignore MTU-exceeded conditions.  The packet
length limits are required only for Ethernet "cable mode" operations
where collissions must be detected.  In point-to-point Full-Duplex
service, this is obviously a non-issue and an FDDI MTU would work just
fine.

So if there was an "official" (ie, interoperagble) large-packet mode
and somebody built a 100baseTX switch that could handle jumbograms,
then I think that Full-Duplexed Switched 100baseTX *would* be the
medium of choice for many, many tasks - moderate-sized exchange points
being one of them.  Heck, I'd use it for interior wiring in my
superhubs.

But there are customers for whom end-to-end MTU is a buying issue.
Bogus or not, it is a very real issue.

	-mo





More information about the NANOG mailing list