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Traffic Engineering With MPLS (MPLS-TE)
2.1 INTRODUCTION
Controlling the path taken by traffic through a network is called traffic engineering (TE). There are many reasons why network operators want to influence the path traffic is taking in their networks. The most popular reason is improving utilization of network resources. The goal is simple: avoid a situation where parts of the network are congested while others are underutilized. Other reasons for using traffic engineering include ensuring that the path has certain characteristics (e.g. it does not use high-latency links), ensuring that transmission resources are available along a particular path, and determining which traffic gets priority at a time of resource crunch (e.g. following a link cut).
This chapter describes why MPLS is a useful technology for implementing traffic engineering and how it accomplishes the goal of steering traffic around the network.
2.2 THE BUSINESS DRIVERS
Influencing the path that traffic takes in the network can increase revenues in two ways:
1. Offering new services with extra guarantees.
2. Lowering the investment in new network resources (primarily band-width) by improving the utilization of existing resources.
‘Offering new services’ means any guarantee that the operator can charge extra money for. One example is the ‘guaranteed bandwidth service’, which simply means that a certain amount of bandwidth is available for a particular customer's traffic, both in the steady state and under ...
