Path computation element in telecom networks: Recent developments and standardization activities

This paper provides an overview of the recent developments in research and the IETF standardization body on using a path computation element in complex telecom networking scenarios such as the multi-layer and multi-domain cases. Implications on the control plane when using such element are addressed as well as the required protocol extensions. The emerging impairment-aware routing and wavelength assignment problem is extensively treated for networks using lightpaths.