The value of tmnxOamP2mpLspTrMapAddrType indicates the type of
downstream interface address specified by tmnxOamP2mpLspTrMapDSIfAddr.
The only valid values for tmnxOamP2mpLspTrMapAddrType are
'ipv4Address', 'ipv4Unnumbered', 'ipv6Address' and 'ipv6Unnumbered'.