Indicates if this PE is the upstream (sending) or the
downstream (receiving) router for the multicast routing entry
specified by ciscoMvpnMrouteMvrfSource and
ciscoMvpnMrouteMvrfGroup in the context MVRF specified by
mplsVpnVrfName.
Note that there may be two rows for the same multicast
routing entry if the traffic is bi-directional, one row
for PE as an upstream router the other for PE as the
downstream router.