Thursday, November 13, 2008

MPLS VPNs with Static Routing Complete

Points to remember when configuring MPLS VPNs:

First create the vrf and associate the rd and import/export rules
Next assign the interfaces to the vrf and reapply IP addresses
Then configure the BGP vpnv4 address family, activating the other PE router and send both communities
Also under BGP, configure the ipv4 vrf address family, redistributing as appropriate
Finally, configure any necessary ip route vrf's.

Use show ip route vrf *, show ip bgp vpnv4 all, and ping vrf to verify connectivity

I really need to commit to memory when to use the vpnv4 address family and when to use the ipv4 vrf address family. It makes sense conceptually. The vpnv4 family includes the extended communities, and basically acts as a type of tunnel between PE routers. Then, each ipv4 vrf is like a pvc inside of that tunnel. Finally, the vrf itself describes what routes get leaked between each individual vrf.

The router uses rd's to keep track of vrf's. We use the vrf name to associate the vrf with interfaces and bgp.

The router uses rt's to advertise vrf's across vpnv4 through the use of extended communities.

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