The unique value which identifies this IP address entry for
this interface of this virtual router in the Tmnx system.
Those row entries with vRiaIndex = 1 represent the primary
IP address for the interface identified by the vRtrID and
vRtrIfIndex pair. Row entries with other values for vRiaIndex
are secondary IP addresses. There must always be a primary
IP address assigned an interface. This implies that if the
primary address row is deleted, the secondary rows are also
deleted.