Introduction To Vpls And Supported Standards; Introduction To Vpls; Chapter 1 Introduction To Vpls And Supported Standards - Juniper EX9200 Features Manual

CHAPTER 1
Introduction to VPLS and Supported
Standards

Introduction to VPLS

Copyright © 2016, Juniper Networks, Inc.
Introduction to VPLS on page 3
Supported VPLS Standards on page 4
VPLS is an Ethernet-based point-to-multipoint Layer 2 VPN. It allows you to connect
geographically dispersed Ethernet local area networks (LAN) sites to each other across
an MPLS backbone. For customers who implement VPLS, all sites appear to be in the
same Ethernet LAN even though traffic travels across the service provider's network.
NOTE: In ACX Series routers, VPLS configuration is supported only on
ACX5048 and ACX5096 routers.
VPLS, in its implementation and configuration, has much in common with a Layer 2 VPN.
In VPLS, a packet originating within a service provider customer's network is sent first to
a customer edge (CE) device (for example, a router or Ethernet switch). It is then sent
to a provider edge (PE) router within the service provider's network. The packet traverses
the service provider's network over a MPLS label-switched path (LSP). It arrives at the
egress PE router, which then forwards the traffic to the CE device at the destination
customer site.
NOTE: In the VPLS documentation, the word router in terms such as PE router
is used to refer to any device that provides routing functions.
The difference is that for VPLS, packets can traverse the service provider's network in
point-to-multipoint fashion, meaning that a packet originating from a CE device can be
broadcast to all the PE routers participating in a VPLS routing instance. In contrast, a
Layer 2 VPN forwards packets in point-to-point fashion only.
The paths carrying VPLS traffic between each PE router participating in a routing instance
are called pseudowires. The pseudowires are signaled using either BGP or LDP.
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