A Contention Detection Scheme for Lightpath Restoration in GMPLS Networks

In wavelength-routed networks based on GMPLS control plane, lightpaths can be dynamically established upon distributed resource reservation performed by RSVP-TE protocol. Resource contentions may occur in the backward signaling when two or more RSVP-TE instances concurrently attempt to reserve the same wavelength (backward blocking). This paper proposes a contention detection (CD) scheme, compliant with RSVP-TE, that detects possible resource contentions and adapts the wavelength selection strategy accordingly. CD scheme is applied to restoration of the lightpaths disrupted by a single-link failure. Simulation results show that the CD scheme is effective in mitigating the backward blocking and thus the overall blocking.