© 2001, Myricom, Inc.
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Revision: 27 August 2001
through a Clos
spreader network
inside of the backplane to the lower row of 16
leaf
XBar16s,
which are packaged on
port line cards
(red boxes). These port line cards have up to 8 Myrinet
ports through their front panel, and 8 Myrinet-SAN ports at connectors to the backplane.
Myricom supplies different port line cards in which the front-panel ports are Myrinet Fiber,
Serial, SAN (switchable between SAN-2000 and SAN-1280), or (legacy) LAN.
An M3-E128 enclosure with no line cards, allowing a view of part of the backplane
A port line card with connectors to the backplane on the back,
and connectors to external links on the front panel
The topology is a full-bisection Clos network with any combination of port line cards inserted or
omitted. For example, you could plug 10 port line cards into the M3-E128 enclosure to support
up to 80 hosts. Ten of the ports on each of the 8 spine XBar16s would be used, and the other 6
ports on each XBar16 would be unused. The 8 10-port spine switches would have exactly the
capacity required to carry traffic between 80 hosts. Even with only two line cards, the network is
a full-bisection Clos topology. The spine would be 8 2-port switches, which can carry all of the
traffic between the two line cards.