Chapter 4. Initial configuration 123
4.6.2  Setting the local port mask
Consider the example fabric port configuration that is shown in Figure 4-42.
Figure 4-42   Example fabric port configuration
This configuration includes the following characteristics:
/SM590000It consists of four nodes, where nodes 1 and 2 are in a system at site A and nodes 3 and 4 
are in a system at site B.
/SM590000Each site has two switches (switch 1 and 2 at site A; switch 3 and 4 at site B).
/SM590000Each node has two adapters (A and B).
/SM590000Each adapter has four ports where the port is named P nodeid adapterid portnumber; for 
example, port 3 on adapter B of node 4 is named P4B3. 
The positions in the mask represent the Fibre Channel I/O port IDs with ID 1 in the rightmost 
position. In this example, ports A1, A2, A3, A4, B1, B2, B3, and B4 correspond to FC I/O port 
IDs 1, 2, 3, 4, 5, 6, 7 and 8.
To set the local port mask, use the chsystem command. Limit local node-to-node 
communication to ports A1, A2, A3, and A4 by applying a port mask of 00001111 to both 
systems, as shown in Example 4-1. 
Example 4-1   Setting a local port mask using the chsystem command
IBM_Storwize:ITSO:superuser>chsystem -localfcportmask 00001111
IBM_Storwize:ITSO:superuser>