IBM System Storage Subsystem DS5020 - Manual (Page 116)

In Figure 57, the Fibre Channel switches are connected together via the inter-switch
link (ISL) to form a single SAN fabric.
In Figure 58, the Fibre Channel switches are connected together via the inter-switch
link (ISL) to form a dual SAN fabric.
In Figure 59 on page 87, the Fibre Channel switches are not connected together.
Each switch forms its own SAN fabric.
Host system
with two host
adapters
Host system
with two host
adapters
Switch Switch
Interswitch link
DS5020
Figure 57. Example of a single SAN fabric configuration
DS5020
Host system
with two host
adapters
Host system
with two host
adapters
Switch Switch
Figure 58. Example of a dual SAN fabric configuration
86 IBM System Storage DS5020 Storage Subsystem: Installation, User’s, and Maintenance Guide