Network Planning and Design - Traffic Engineering

Traffic Engineering

Comparing to network engineering, which adds resources such as links, routers and switches into the network, traffic engineering targets to change traffic paths on the existing network to alleviate traffic congestion or accommodate more traffic demand.

This technology is critical when the cost of network expansion is prohibitively high and network load is not optimally balanced. The first part provides financial motivation for traffic engineering while the second part grants the possibility of deploying this technology.

The available technologies for traffic engineering include MPLS and ATM for current Internet backbone. For example, MPLS allows carriers to provision LSPs with dynamic or explicit routes. The dynamic routes is controlled by CSPF while the explicit routes are optimized in an offline tool or through a path computation element which is under study by IETF. Fast reroute has been implemented by major vendors, such as Cisco and Juniper Networks, to provide localized resilient capability for MPLS networks. End-to-end protection is an alternative resilient approach. It provisions a backup route for each primary route. Pre-planning enough bandwidth for these backup routes is one of the active topics for survivable network design.

Provisioning a large number of LSPs also brought up a scalability problem. Various solutions have been proposed and it is still an active topic under study.