Distributed Computation of Shared Backup Path in Mesh Optical Networks Using Probabilistic Methods

Abstract

Abstract-In this paper we assess the benefits of using statistical techniques to ascertain the shareability of protection channels when computing shared mesh restored lightpaths in optical mesh networks. These optical networks support wavelength conversion everywhere as a byproduct of the electronic nature of the switching in the OEO optical cross-connect used. Current deterministic approaches require a detailed level of information proportional to the number of active lightpaths. Although this is not an issue for good size networks in the foreseeable future, these approaches are not practicable for distributed route computation involving larger networks. On the other hand, distributed approaches that do not make use of shareability information require a significant amount of additional capacity compared to a centralized approach with access to complete shareability information. With the proposed approach we show that even with less information, independent of the amount of traffic demand, it is possible to predict the shareability of protection channels with remarkable accuracy. In addition, we propose a local distributed channel assignment scheme that is used in conjunction with our distributed route computation proposal to assign shared channels when provisioning the backup path. This channel assignment scheme can also be used to further optimize capacity usage in individual links upon certain events or at regular intervals. Experiments are provided, that demonstrate that our approach yields faster computation times with no significant penalty in terms of capacity usage than a centralized approach using complete information.

Survivability: Wavelength Recovery for Node and Link Failure in All Optical Networks

“…The concept of protected capacity working envelope has also been recently considered for adapting static design solutions to dynamic traffic scenarios to improve restoration guarantees. A detailed discussion on the issues related to dynamic restoration approaches may be found in [2], [12], [13].…”

A Comparison of Path Protections with Availability Concern in WDM Core Network

“…There are plenty of reasons for connection failures in a WDM core networks. Shared Risk Group (SRG) may consist of all the optical lines within the same fiber, or within the same cable wrapper or those who traverse through the same conduit [1]. Failures of any SRG components such as amplifier or conduit may affect multiple connections.…”

“…However, the wavelength continuity constraint stated that lightpath must occupy the same wavelength on fiber link through which it traversed for purpose of interference avoidance. A transparent WDM optical network can ignore the said constraint by utilizing Optical Cross Connect (OXC) capable of transferring ten terabits per seconds [1] at nodes for routing connections without any intermediate electronic conversion. M eanwhile, limited WDM core networks are only capable for limited wavelength conversion or when OXC is placed sparsely in network.…”

Dynamic routing for shared path protection in multidomain optical mesh networks

“…We assume that links are not bundled together and thus a failure affects at most one link (which is not the case in Ref. [3]). We assume also that every network node has optical-electrical-optical (OEO) treatment so that subwavelength switching and wavelength assignment are easy to handle.…”