Suggested vector scheme with crankback mechanism in GMPLS-controlled optical networks

The GMPLS distributed control plane is used in wavelength-routed networks to dynamically establish end-to-end lightpaths. During the signaling phase, lightpath requests can be blocked due to lack of available resources or due to resource contentions. Blocking due to resource contentions is the dominant source of blocking, when network is lightly loaded or lightpath requests are highly dynamic. To reduce the contentions, solutions based on extension of GMPLS signaling protocol (i.e., RSVP-TE) can be exploited, such as the Suggested Vector (SV) scheme proposed by the authors. This paper, first, thoroughly reviews the SV scheme and, then, it compares different wavelength selection policies to be applied to the SV scheme. Also, crankback mechanism of RSVP-TE is explored as a way to reduce the blocking. A comprehensive simulation analysis is carried out in a GMPLS-controlled wavelength-routed network, based on RSVPTE and OSPF-TE routing protocol. Simulation results demonstrate the effectiveness of SV scheme and crankback mechanism in strongly reducing resource contentions.