The value of tmnxOamVccvPingCtlSaiiPrefix specifies the prefix of the
Source Attachment Individual Identifier (SAII) to be used when testing
a FEC 129 AII Type 2 pseudowire.
At most one of tmnxOamVccvPingCtlSdpIdVcId and
tmnxOamVccvPingCtlSaiiPrefix can be set to a non-default value on a
particular row.
A value of zero indicates that no prefix has been configured.