TABLE OF CONTENTS In this chapter, we will discuss the following topics:
MPLS architecture
MPLS implementation
MPLS operation
MPLS support of DiffServ
The amount of traffic over the IP network is growing so explosively that it is doubling just about every few months. And yet, today's IP network is not scaling rapidly enough to meet this demand. In connection-oriented networks such as the circuit switched Time Division Multiplex (TDM) networks, where circuits are organized in trunk groups and switching can be used to select routing in real time, traffic engineering can be used to balance the traffic across the network.
In most commercial IP networks, routing is static, and all IP traffic automatically takes the "shortest" path. For this reason, the bandwidth in the IP network is not optimally distributed. While one part of the IP network is congested, other parts of the network may be lightly loaded. Unlike the circuit switched network, the IP network does not easily lend itself to traffic engineering.
The Multi-Protocol Label Switching (MPLS) is a solution to the problem faced by the IP network and, to some extent, the ATM network. MPLS provides a mechanism for traffic engineering for packet networks such as IP and ATM networks.
In particular, MPLS can now support the IP DiffServ, and can be used in conjunction with the IP DiffServ.
The ATM network has a connection-oriented network infrastructure based on virtual connections and is ideally suited for MPLS. The word "multiprotocol" in MPLS means...
