Q-Logic SANBOX2-8C Manuel D’Utilisation
3 – Planning
Multiple Chassis Fabrics
59042-00 A
3-3
3.2.2
Common Topologies
This section describes three commonly used topologies:
■
Cascade
■
Mesh
■
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 sequential structure, that
bandwidth will be shared by traffic between devices on other chassis.
400 MB/s in full duplex. However, because of the sequential structure, that
bandwidth will be shared by traffic 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
Note:
Domain ID reassignment is not reflected in zoning that is defined by
domain ID/port number pair or Fibre Channel address. You must
reconfigure zones that are affected by domain ID reassignment. To
prevent zoning definitions from becoming invalid, use the Set Config
Switch command to lock the domain IDs. Refer to the
domain ID/port number pair or Fibre Channel address. You must
reconfigure zones that are affected by domain ID reassignment. To
prevent zoning definitions from becoming invalid, use the Set Config
Switch command to lock the domain IDs. Refer to the
.