vRtrLdpPeerAddress is an index for the row entry and is used
mutually exclusively with the vRtrLdpIfIndex field. If the
vRtrLdpIfIndex field is 0, then the vRtrLdpPeerAddress is the
IP address of the targeted peer and must be non-zero.
Otherwise, vRtrLdpIfIndex refers to the LDP interface index
and its vRtrLdpPeerAddress is 0.0.0.0