2. Distributed traffic engineering

2.1 General principles and constrained path calculations

Unlike the standard IP network, where each router participates in selecting the best path, traffic engineering allows the network's entry router to calculate the end-to-end path according to the constraints given to it, and thus impose its decision on the other routers on the path.

To perform its path calculation, the ingress router needs to know the entire network topology and the characteristics of its components (bandwidth, link latency, etc.). The use of a link-state routing protocol such as OSPF or IS-IS is therefore mandatory when implementing traffic engineering.

Thanks to the data retrieved by the routing protocol, each router can create a network topology database on which...