OSPF and IS-IS: Choosing an IGP for Large-Scale Networks

Chapter 11. Extensions for MPLS Traffic Engineering

As mentioned in Chapter 9, one trend in modern router design is to assign the two fundamental functions of route processing and packet forwarding to separate physical modules. Another way to view this trend is as a separation of intelligence—which is processor intensive and hence time-consuming—from basic packet forwarding, improving the performance of both. This same trend of separating intelligence from packet forwarding can be seen in large networks as a whole with the increasingly widespread adoption of Multiprotocol Label Switching (MPLS). The fundamental idea behind MPLS is to push intelligence to the edge of the network, leaving the core free to do little more than forward packets.