PE Role in MPLS
- PE router:
- An LSR that shares a link with at least one Customer Edge router,
- edge of MPLS VPN, IBGP & VRF tables
- PE & P routers can together label switch packets from the ingress PE to the egress PE router.
- PE .have several other duties:
- Learn customer routes
- & keep track of which routes belong to which customer.
- Exchange routes with connected CE routers from various customers.
- To keep the track of the possibly overlapping prefixes.
- PE routers do not put the routers in normal IP routing table
- instead , PEs store routes in separate per-customer routing tables, called VRFs
- To exchange these customer routes with other PEs use IBGP.
- never advertise these routes to P routers.
- PEs advertise Route Targets in BGP updates as BGP Extended Community Path Attributes (PAs)