The value of vRtrPimNgIfGrpSrcSourceAddress indicates the source
address of the multicast sender. It will be zero if the
vRtrPimNgIfGrpSrcType is 'starG' and it will be the address of
the Rendezvous Point(RP) if the vRtrPimNgIfGrpSrcType is 'starStarRP'.