Survey on Path Computation Element extensions for Spectrum Switched Optical Networks

Recently, Spectrum Switched Optical Networks (SSON) have been receiving much interest from the research community due to their network performance benefits. Some of these benefits include the possibility of enabling either super channels or sub-wavelength channels, which meet better the granularity of Internet needs. Due to its specific routing and resource assignment characteristics, SSON's primordial procedures, as routing and spectrum assignment (RSA), cannot be suitably assisted by current related protocols from Wavelength Switched Optical Network (WSON). For this very reason, a SSON control plane architecture and protocols should be extended from WSON's control plane in order to be able to support specific information exchange. This paper presents the most recent Path Computation Element (PCE) architecture extension proposals in the literature, which intend to meet SSON specific requirements.