Introduction To Mpls L2Vpn; Chapter 4 Mpls L2Vpn Configuration - 3Com 3C13636 Configuration Manual

3Com Router 3000 Ethernet Family
Configuration Guide

Chapter 4 MPLS L2VPN Configuration

4.1 Overview

4.1.1 Introduction to MPLS L2VPN

ATM-based and FR-based VPNs have gained widespread applications, which can
enable different VPNs to share the network infrastructure of the same service provider.
Yet, such traditional VPNs are not perfect due to some drawbacks, for example,
Dependency on dedicated medium like ATM and FR. To provide the ATM-based
VPN service, a service provider must construct a nationwide ATM network. If this
service provider wants to develop the FR-based service, he has to construct a
separate nationwide FR network. This is absolutely an enormous waste in terms of
network construction.
The VPN deployment is rather complex. This becomes more evident when adding
a site onto the existing VPN, in which case, the configurations of all the edge
nodes accessing this VPN site must be modified.
Some substitution solutions emerged in the process of solving these inherent
drawbacks of traditional VPN. MPLS L2VPN is one among them. As the name implies,
MPLS L2VPN provides L2 VPN service based on MPLS networks. With this solution,
the service provider can provide the L2VPN service based on different media, such as
ATM, FR, VLAN, Ethernet, and PPP, on the same MPLS network. Still, this MPLS
network can provide other common services like IP, L3 VPN, traffic engineering, and
QoS. This approach thus enormously saves the investment on network infrastructure.
Simply put, MPLS L2VPN transparently transmits L2 user data over MPLS networks.
From the perspective of a user, this MPLS network is a L2 switching network, through
which, L2 connection can be set up between sites. Take ATM as an example. You can
connect a CE to another remote CE by configuring an ATM VC across an MPLS
network. The interconnection thus achieved is the same as the interconnection
implemented using an ATM network.
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Chapter 4 MPLS L2VPN Configuration