MPLS Fundamentals

The Need for MPLS TE

Routing in IP networks is governed by the need to get the traffic across the network as quickly as possible. That is why IP routing is based on the least-cost routing principle. Every IP routing protocol has a cost associated with the links in the networks. The accumulation of the cost of every link of a path is used to calculate the smallest cost path to forward traffic through the network. That cost is a single metric that is assigned to a link (for instance, Open Shortest Path First [OSPF] and Intermediate System-to-Intermediate System [IS-IS]), a composite metric (for instance, Interior Gateway Routing Protocol [IGRP] and Enhanced Interior Gateway Routing Protocol [EIGRP]), or simply a hop count (for instance, Routing ...