Q-Logic 8C Manuale Utente
3 – Planning
Multiple Chassis Fabrics
59042-01 A
3-3
3.2.2
Common Topologies
This section describes three commonly used topologies:
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Cascade
■
Mesh
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Multistage®
3.2.2.1
Cascade Topology
A cascade topology describes a fabric in which the switches are connected in a
line. If you connect the last switch back to the first switch, you create a
cascade-with-a-loop topology as shown in
line. If you connect the last switch back to the first switch, you create a
cascade-with-a-loop topology as shown in
. The loop reduces latency
because any switch can route traffic in the shortest direction to any switch in the
loop. The loop also provides failover should a switch fail.
loop. The loop also provides failover should a switch fail.
has the following characteristics:
■
Each chassis link contributes up to 200 MB/s of bandwidth between chassis,
400 MB/s in full duplex. However, because of the structure of the cascade
topology, the bandwidth will be shared between devices on other chassis.
400 MB/s in full duplex. However, because of the structure of the cascade
topology, the bandwidth will be shared between devices on other chassis.
■
Latency between any two ports is no more than three chassis hops.
■
24 Fibre Channel ports are available for devices.
Figure 3-1. Cascade-with-a-Loop Topology