Vpls Overview - Alcatel-Lucent OmniSwitch 6850-48 Network Configuration Manual

Configuring VPLS

VPLS Overview

A VPLS-capable network consists of Customer Edges (CE), Provider Edges (PE), and a core MPLS
network. The CE device is a router or switch located at the customer's premises and is connected to the PE
via an Attachment Circuit (AC). In the case of VPLS, it is assumed that Ethernet is the Layer 2 protocol
used between the CE and the PE.
The PE device is where the services originate and terminate and where all the necessary tunnels are set up
to connect to all the other PEs. As VPLS is an Ethernet Layer 2 service, the PE must be capable of Media
Access Control (MAC) learning, bridging, and replication on a per-VPLS basis.
The PE routers that participate in a VPLS are connected using MPLS Label Switched Path (LSP) tunnels
in a full-mesh composed of mesh Service Distribution Points (SDPs). Multiple VPLS services are
supported over the same LSP tunnels.
Signaling is used to negotiate a set of ingress and egress virtual circuit (VC)/pseudowire (PW) labels on a
per-service basis. The VC labels are used by the PE routers for de-multiplexing traffic arriving from
different VPLS services over the same set of LSP tunnels.
VPLS is provided over MPLS by:
•
Connecting bridging-capable PE routers with a full mesh of MPLS LSP tunnels.
•
Negotiating per-service VC/pseudowire labels using draft-Martini encapsulation.
•
Replicating unknown and broadcast traffic in a service domain.
•
Enabling MAC learning over tunnel and access ports.
•
Using a separate forwarding information base (FIB) per VPLS service.
The IP/MPLS core network interconnects the PEs but does not participate in the virtual private network
(VPN) functionality. Traffic is simply switched based on the MPLS labels.
The following illustration provides an example of an MPLS-based VPLS network:
OmniSwitch AOS Release 6 Network Configuration Guide September 2009
VPLS Overview
page 11-7