The (optional) routing index of this queue.
Usage: This (optional) routing index, for queue indirection
mapping, specifies 'xcmSvcMonQueueIndex' for the NEXT queue
closer to (or on) this host system, or zero if none.
Usage: It is common for more than one off-system (remote) queue
to be forwarded to the same on-system (local) queue. Multiple
off-system (remote) entries in the 'xcmSvcMonQueueTable' (for a
given device) MAY forward to the same on-system (local) entry.