Reasons for Hidden Routes

A

In a Multiprotocol Label Switching (MPLS) VPN environment, VPN routes are distributed among the Provider Edge (PE) routers. These routers have to maintain a separate routing table to store VPN routes, known as the Virtual Routing and Forwarding (VRF) table. When a packet arrives at a PE router, the router looks up the destination IP address in the VRF table and determines the outgoing interface and label for the packet.

If VPN routes are hidden on the PE router, it means that they are not being advertised or distributed properly. There could be several reasons for this, including:

A. The protocol next-hop is not found in inet.3: The inet.3 table stores the IP routing information, including the next-hop information. If the next-hop for a VPN route is not found in this table, the route will not be advertised or distributed.

B. The protocol next-hop is not found in mpls 0: The mpls.0 table stores the MPLS label information. If the next-hop for a VPN route is not found in this table, the label will not be assigned and the route will not be distributed.

C. The protocol next-hop is not found in bgp I3vpn 0: BGP is used to exchange VPN routes among PE routers. If the next-hop for a VPN route is not found in the BGP I3 VPN table, the route will not be advertised or distributed.

D. The protocol next-hop is not found in inet 2: The inet.2 table stores the MPLS LSP information. If the next-hop for a VPN route is not found in this table, the label will not be assigned and the route will not be distributed.

To resolve the issue of hidden VPN routes, the network administrator should investigate the cause and take appropriate actions. This may involve checking the routing protocols, verifying the next-hop information, and troubleshooting any configuration or connectivity issues.