The value of tmnxPtpPeerLocalPortNumber indicates the PTP port number
assigned by the local clock and used when communicating with the
remote clock.
If tmnxPtpClockClockType is either 'ordinarySlave (1)' or
'ordinaryMaster (2)', tmnxPtpPeerLocalPortNumber has a value of 1.
The value of this object corresponds to the
portDS.portIdentity.portNumber data set member defined in IEEE Std
1588-2008.