The MAC address associated with a service.
An additional nodal MAC address by which an I-SID
can be reached may be advertised, in which case
traffic to this MAC follows a forwarding path identical
to that taken to reach the corresponding SYSID (nodal) MAC.
If no additional MAC is advertised this will be the
SYSID MAC.
A value of 0 is a wildcard for the MAC address.
An additional nodal MAC address by which an I-SID
can be reached may be advertised, in which case
traffic to this MAC follows a forwarding path identical
to that taken to reach the corresponding SYSID (nodal) MAC.
If no additional MAC is advertised this will be the
SYSID MAC.
A value of 0 is a wildcard for the MAC address.