Question

A service provider engineer is configuring a new customer VRF on a PE router and enters 'rd 65001:100' under the VRF definition. A junior colleague asks what functional role this route distinguisher value plays in the MPLS L3VPN control plane. Which statement correctly describes the purpose of the RD in this scenario?

Accepted Answer

It is prepended to the customer IPv4 prefix to create a globally unique 96-bit VPNv4 prefix so overlapping customer address space can be carried in MP-BGP.

Answer

It determines which VPNv4 routes are imported into and exported from the VRF between PE routers.

Answer

It is used by LDP to allocate a per-VRF label that identifies the egress VRF at the receiving PE.

Answer

It authenticates the MP-BGP session between PE routers before VPNv4 prefixes are exchanged.