The task of mapping traffic flows onto an existing physical topology is called traffic engineering. Traffic engineering provides the capability to move traffic flow away from the shortest path selected by the interior gateway protocol (IGP) and onto a potentially less congested physical path across a network.
Traffic engineering provides the capabilities to do the following:
Route primary paths around known bottlenecks or points of congestion in the network.
Provide precise control over how traffic is rerouted when the primary path is faced with single or multiple failures.
Provide more efficient use of available aggregate bandwidth and long-haul fiber by ensuring that subsets of the network do not become overutilized while ...