Configuring Mpls L3Vpn; Overview - HP HSR6800 Configuration Manual

Configuring MPLS L3VPN

This chapter describes only MPLS L3VPN configuration. For information about MPLS basics, see
"Configuring basic MPLS." For information about BGP, see Layer 3—IP Routing Configuration
Guide.

Overview

MPLS L3VPN is a PE-based L3VPN technology. It uses BGP to advertise VPN routes and uses
MPLS to forward VPN packets over service provider backbones.
MPLS L3VPN provides flexible networking modes, excellent scalability, and convenient support for
MPLS QoS and MPLS TE.
MPLS L3VPN is comprised of the following types of devices:
•
Customer edge device—A CE device resides on a customer network and has one or more
interfaces directly connected to service provider networks. It can be a router, a switch, or a host.
It can neither "sense" the presence of any VPN nor does it need to support MPLS.
•
Provider edge device—A PE device resides at the edge of a service provider network and
connects one or more CEs. On an MPLS network, all VPN services are processed on the PEs.
•
Provider device—A P device is a core device on a service provider network. It is not directly
connected to any CE. It has only basic MPLS forwarding capability.
Figure 65 Network diagram for MPLS L3VPN model
VPN 1
Site 1
CE
CE
Site 2
VPN 2
CEs and PEs mark the boundary between the service providers and the customers.
After a CE establishes an adjacency with a directly connected PE, it advertises its VPN routes to the
PE and learns remote VPN routes from the PE. A CE and a PE can use BGP, an IGP, or static routing
to exchange routing information.
After a PE learns VPN routing information from a CE, it uses BGP to exchange VPN routing
information to other PEs. A PE maintains routing information only for directly connected VPNs rather
than all VPNs on the provider network.
A P router maintains only routes to PEs and does not deal with VPN routing information.
P
PE
P
P
PE
P
PE
237
VPN 2
Site 3
CE
CE
Site 4
VPN 1