A contention resolution scheme.P-cycle auto-switching(PCAS).is proposed in wavelength-switched optical networks(WSONs) based on generalized multi-protocol label switching(GMPLS) to solve backward blocking.This system permits the preferable request and switches the other to a backup path generated by the P-cycle.Simulation results show that the PCAS scheme is effective in mitigating backward blocking, especially under concentrated load.
Current generalized multi-protocol label switching(GMPLS) standards do not include adequate models for wavelength-switched optical networks(WSON) in recovery mechanisms.In this letter,GMPLS/path computation element(PCE) extensions are applied for the restoration of the lightpaths disrupted by collision or optical impairment.A reserved deflection routing scheme is proposed to achieve fast restoration. It uses the expanded PCE component to compute and assign the backup paths for lightpath recovery. Numerical results demonstrate that this scheme is effective and low cost.
To improve the restoration performance of a multicast service of multi-protocol label switching transport profile (MPLS-TP) enabled optical network,this letter proposes a local-node initiated fast restoration (LNIFR) scheme for MPLS-TP optical multicast service.The proposed scheme allows the local node to establish a segment of fast loopback label switch path by the local node along the upstream of the failed node or link to the nearest downstream node.The fast restoration of optical multicast trees is realized through this part restoration,which focuses on failed node or link.Simulation analysis and results demonstrate that the new scheme outperforms the other schemes in terms of restoration time and success rate.
We introduce a novel network-coding scheme that can be implemented in all-optical multicast networks.A simple and successful module based on the all-optical XOR gate is designed to realize the network coding scheme.The module is a key hardware component in realizing the proposed scheme.The working principle and the experimental results of the module are also presented.Experimental results show that the function of the module is sufficient in satisfying the requirements of the proposed network coding scheme.
Different multicasting schemes in optical packet switched networks are discussed,including the parallel mode,serial mode,and hybrid mode multicasting schemes.Simulated modeling technique is applied to compare the network-level performance of the three multicasting schemes.A conclusion can be drawn from the results that since the hybrid-mode multicasting scheme can increase the multicast success ratio and reduce the packet retransmission times compared with the other two schemes,it is the best choice for delivering multicasting sessions in the optical packet switched networks.
An optical signal-to-noise ratio (OSNR) aware lightpath provisioning mechanism (OSNR-LPM) is proposed for distributed optical networks. This OSNR-LPM takes the OSNR value of the lightwave along the lightpath into consideration when establishing the lightpath for the connection request using resource reservation protocol-traffic engineering (RSVP-TE). Moreover, the OSNR-LPM makes full advantages of the OSNR monitoring function in each node and assigns the lightwave by judging the OSNR value carried by the signaling message in order to guarantee the reliable establishment of the lightpath in the data plane. The simulation results show that the OSNR-LPM outperforms other lightpath assignment mechanisms in terms of real blocking probability in the data plane.
