Local port Selection

Multiple port/Multiple CA support: when no IB device or port is specified (see the "local umad parameters" below), the libibumad library selects the port to use by the following criteria:

1. the first port that is ACTIVE.
2. if not found, the first port that is UP (physical link up).

If a port and/or CA name is specified, the libibumad library attempts to fulfill the user request, and will fail if it is not possible.

For example:

ibaddr                 # use the first port (criteria #1 above)
ibaddr -C mthca1       # pick the best port from "mthca1" only.
ibaddr -P 2            # use the second (active/up) port from the first available IB device.
ibaddr -C mthca0 -P 2  # use the specified port only.