User`s guide

Chapter 2. IBM TotalStorage Enterprise Storage Server configuration 167
2.7.3 Configuring host FC ports for FC-SW and FC-AL
Now, as we have selected the first ESS FC port, we are going to configure this
and two other ports to be able to communicate with our host FC ports. The first
two ports we configure for use in a switched fabric environment and the second
are for use in an arbitrated loop environment.
Selecting the topology for the ESS FC ports
The pull down list in the FC Port Attributes field as shown in Figure 2-123, is for
selecting the topology the port is going to be connected to.
Figure 2-123 Pull down list, selected port currently undefined
The selected ESS FC port in bay one adapter three we start with is unconfigured.
Because of this, we can choose by selecting between Fibre Channel Point to
Point and Fibre Channel Arbitrated Loop. If a port is already configured for one
topology and it has to be changed to another, the port must first be undefined.
Then it is possible to choose the appropriate topology.
We can choose between Fibre Channel Arbitrated Loop for FC-AL and Fibre
Channel Point-to-Point for FC-PP and for FC-SW. Some adapters — for
example, the IBM FC6227 — operate in arbitrated loop mode even though they
are directly connected to an ESS. This means that the ESS port will have to be
configured in FC-AL mode.