66 Fabric OS Administrator’s Guide
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Inter-switch links
4

Inter-switch links

An inter-switch link (ISL) is a link between two switches, E_Port-to-E_Port. The ports of the two
switches automatically come online as E_Ports, once the login process finishes successfully. For
more information on the login process refer to Chapter 1, “Understanding Fibre Channel Services”.
FIGURE 6 New switch added to existing fabric
You can connect new switches to existing switches and this expands your fabric. Figure 6 shows a
new switch being added into an existing fabric. The thicker red line is the newly formed ISL. When
connecting two switches together, you need to verify that the following parameters are different:
Domain ID
Switch name
Chassis name
You must also verify the following fabric parameters are identical on each switch for a fabric to
merge:
R_A_TOV
E_D_TOV
Data field size
Sequence level switching
Disable device probing
Suppress class F traffic
Per-frame route priority
BB credit
PID format