Title :
Protection mechanisms for optical WDM networks based on wavelength converter multiplexing and backup path relocation techniques
Author :
Gowda, Sunil ; Sivalingam, Krishna M.
Author_Institution :
Expedia, Seattle, WA, USA
Abstract :
This paper studies the problem of designing survivable optical wavelength division multiplexed (WDM) networks. A wavelength-routed wide area backbone network supporting circuit-switched traffic is considered. This paper also considers the use of optical wavelength conversion technology which has been shown to help improve network performance. However, wavelength conversion is still an expensive technology and using optical conversion could potentially result in signal quality degradation. In survivable networks, protection against failures is provided using backup paths that are determined when a session is established. In this paper, we present three primary and backup route computation mechanisms that attempt to improve overall network performance compared to existing solutions. One of the key design goals is to reduce the number of required converters per node. First, we present a routing algorithm, termed conversion free primary routing (CFPR) that computes primary paths without wavelength conversion, as far as possible. Next, we present a converter multiplexing technique that is used to share wavelength converters among multiple backup paths. This significantly reduces the number of connections blocked due to wavelength converter unavailability and reduces the number of wavelength converters required at each node, thus reducing system cost. Finally, we propose a backup path relocation scheme that migrates existing backup paths, whenever needed, to accommodate more primary paths and also to obtain primary routes with fewer hops. This is done to improve network utilization and reduce blocking probability. The proposed techniques are analyzed in detail using a discrete-event simulation model. The results show that significant reduction in blocking probability is possible with the proposed mechanisms. The number of converters required at each node to achieve a given blocking probability is also seen to be four times lower, compared to existing architectures based on static shortest path routing.
Keywords :
circuit switching; discrete event simulation; discrete event systems; optical fibre networks; optical wavelength conversion; telecommunication network reliability; wavelength division multiplexing; CFPR; backup path relocation technique; backup route computation mechanism; blocking probability reduction; circuit-switched traffic; conversion free primary routing; discrete-event simulation model; network performance improvement; network utilization; optical WDM network protection mechanism; optical wavelength conversion technology; routing algorithm; signal quality degradation; static shortest path routing; survivable network; wavelength converter multiplexing; wavelength division multiplexing; wide area backbone network; Circuits; Optical design; Optical fiber networks; Optical wavelength conversion; Protection; Spine; WDM networks; Wavelength conversion; Wavelength division multiplexing; Wavelength routing;
Conference_Titel :
INFOCOM 2003. Twenty-Second Annual Joint Conference of the IEEE Computer and Communications. IEEE Societies
Print_ISBN :
0-7803-7752-4
DOI :
10.1109/INFCOM.2003.1208654