MPLS ××× Notes

Route Targets:

export: redistribute out of the VRF into BGP
import: redistribute into the VRF from BGP

MPLS ××× configuration focuses primarily on control plane functions:

1. creating the VRF and associated RDs and RTs

2. configuring MP-BGP

3. redistributing between the IGP used with the customer and BGP used inside the MPLS cloud.

 

 The planning process must match the exported RT on one PE router to the imported RT on the remote PE, and vice versa, for the two routers to exchange routes with MP-BGP.

VRFs allow PEs to store routes learned from various CEs, even if the prefixes overlap.

The RD allows PEs to advertise routes as unique prefixes, even if the IPv4 prefixes happen to overlap.

Finally, the RT tells the PEs which routes should be added to each VRF, which provides greater control and the ability to allow sites to be reachable from multiple ×××s.