Configuring Vpls; Vpls Overview; Basic Vpls Concepts - HP 10500 SERIES Configuration Manual

Configuring VPLS

This chapter describes how to configure VPLS.

VPLS overview

Virtual Private LAN Service (VPLS), also called "Transparent LAN Service (TLS)" or "virtual private
switched network service," can deliver a point-to-multipoint L2VPN service over public networks. With
VPLS, geographically-dispersed sites can interconnect and communicate over MAN or WAN as if they
were on the same LAN.
VPLS provides Layer 2 VPN services. However, it supports multipoint services rather than the
point-to-point services the traditional VPN supports. With VPLS, service providers can create a series of
virtual switches for customers on the PEs, allowing customers to build their LANs across the MAN or
WAN.

Basic VPLS concepts

CE—Customer edge device. A CE is directly connected to the PE.
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PE—Provider edge device. A PE connects one or more CEs to the service provider network. It maps
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and forwards packets between private networks and public network tunnels. A PE can be a UPE or
NPE.
• UPE—User facing provider edge device. A UPE functions as the user access convergence device.
NPE—Network provider edge device. An NPE functions as the network core PE, resides at the edge
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of a VPLS network core domain, and provides transparent VPLS transport services between core
networks.
VSI—Virtual switch instances maps actual access links to virtual links.
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PW—A pseudo wire is a bidirectional virtual connection between VSIs. A PW consists of two
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unidirectional MPLS virtual circuits (VCs) with opposite directions.
AC—An attachment circuit connects a CE to a PE. It can use physical interfaces or virtual interfaces.
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Usually, all user packets on an AC, including Layer 2 and Layer 3 protocol messages, must be
forwarded to the peer site without being changed.
QinQ—802.1Q in 802.1Q. It is a tunneling protocol based on 802.1Q. It offers a
•
point-to-multipoint L2VPN service mechanism. With QinQ, the private network VLAN tags of
packets are encapsulated into the public network VLAN tags, allowing packets to be transmitted
with two layers of tags across the service provider network. This provides a simpler Layer 2 VPN
tunneling service.
Forwarders—A forwarder functions as the VPLS forwarding table. Once a PE receives a packet
•
from an AC, the forwarder selects a PW for forwarding the packet.
Tunnel—A tunnel, usually an MPLS tunnel, is a direct channel between a local PE and the peer PE
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for transparent data transmission in-between. It is used to carry PWs. A tunnel can carry multiple
PWs.
• Encapsulation—Packets transmitted over a PW use the standard PW encapsulation formats and
technologies: Ethernet and VLAN.
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