The output of some InfiniBand commands identify a node by its GUID. You can determine the switch chip or InfiniBand cable connection associated with that GUID using this procedure.
For example, given the following output from the ibdiagnet command:
-W- lid=0x0055 guid=0x0021283a8389a0a0 dev=48438 Port=21
In this example, the GUID is 0x0021283a8389a0a0 and the port is 21.
For example, GUID 0x0021283a8389a0a0 is truncated to a0a0.
The a0 means that the node is inside of a Sun Datacenter InfiniBand Switch 36. The a means that the node is located in I4 switch chip A, the only switch chip. The port is 21.
For example, using Switch Chip Port to QSFP Connectors and Link LED Routes, I4 switch chip, port 21 routes to connector 1B.