Vpls Over Mpls; Vpls Mac Learning And Packet Forwarding - Alcatel-Lucent 7750 SR Manual

VPLS over MPLS

The VPLS architecture proposed in draft-ietf-ppvpn-vpls-ldp-0x.txt specifies the use of provider
equipment (PE) that is capable of learning, bridging, and replication on a per-VPLS basis. The PE
routers that participate in the service are connected using MPLS Label Switched Path (LSP)
tunnels in a full-mesh composed of mesh SDPs or based on an LSP hierarchy (Hierarchical VPLS
(H-VPLS)) composed of mesh SDPs and spoke SDPs.
Multiple VPLS services can be offered over the same set of LSP tunnels. Signaling specified in
draft-martini-l2circuit-encap-mpls-0x.txt is used to negotiate a set of ingress and egress VC 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:
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VPLS MAC Learning and Packet Forwarding

The 7750 SR edge devices perform the packet replication required for broadcast and multicast
traffic across the bridged domain. MAC address learning is performed by the 7750 SRto reduce
the amount of unknown destination MAC address flooding.
7750 SR routers learn the source MAC addresses of the traffic arriving on their access and
network ports.
Each 7750 SR maintains a Forwarding Information Base (FIB) for each VPLS service instance
and learned MAC addresses are populated in the FIB table of the service. All traffic is switched
based on MAC addresses and forwarded between all participating nodes using the LSP tunnels.
Unknown destination packets (for example, the destination MAC address has not been learned)
are forwarded on all LSPs to all participating nodes for that service until the target station
responds and the MAC address is learned by the 7750 SR associated with that service.
7750 SR OS Services Guide
Connecting bridging-capable provider edge routers with a full mesh of MPLS LSP (label
switched path) tunnels.
Negotiating per-service VC labels using draft-Martini encapsulation.
Replicating unknown and broadcast traffic in a service domain.
Enabling MAC learning over tunnel and access ports (see
Packet Forwarding).
Using a separate forwarding information base (FIB) per VPLS service.
Virtual Private LAN Services
VPLS MAC Learning and
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