Re: value of co-location

[Stephen Stuart <stuart () pa dec com>]

> PS. Also does someone have numbers for the amount of
> buffering in a DEC gigaswitch, and information on their buffer
> managment (i.e. variable length buffers vs fixed length buffers).

The Gigaswitch SCP card has (at last count) 16MB of DRAM for buffering
packets (and other stuff) that get forwarded by the crossbar. The FGL
cards (FDDI line cards) have 1MB of DRAM.

There's a Digital Technical journal article available on-line that
describes the Gigaswitch in detail. The URL is

        http://www.digital.com/info/hpc/sc95/sygiga-dtj.html

Buffer management is discussed in the "Design Issues" section:

        http://www.digital.com/.i/info/hpc/sc95/sygiga-dtj-design.html

Module details (like types and quantities of memory) are listed in the
(hm) "Module Details" section:

        http://www.digital.com/.i/info/hpc/sc95/sygiga-dtj-module.html

We have a Gigaswitch/FDDI at the Palo Alto interconnect, if you'd like
to have a look at one.

Stephen
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Stephen Stuart                          stuart () pa dec com
Network Systems Laboratory
Digital Equipment Corporation