Routing and wavelength assignment in Java Incoporate Code 128 in Java Routing and wavelength assignment

Routing and wavelength assignment generate, create code 128a none in java projects GS1 Data Matrix Introduction The routin awt Code 128A g and wavelength assignment (RWA) problem was introduced in the context of traditional optical wavelength-switching WDM networks in Section 2.5. We have seen that the RWA problem deals with the route selection of lightpaths and the assignment of a wavelength on each WDM link along the selected route.

Apart from the special case of lightpath computation in optical wavelength-switching networks, paths of ner and coarser switching granularity must be computed in GMPLS networks. Waveband switching that deplo code-128c for Java y MG-OXCs, where paths may be ber, waveband, wavelength (lambda), and subwavelength (TDM, packet) label switched paths, as discussed in greater detail in Section 5.2.3.

The RWA problem in waveband-switching networks that use MG-OXCs is in general more involved than that in wavelength-switching networks with ordinary single-granularity OXCs since further constraints must be taken into account apart from the wavelength continuity constraint. As a consequence, several new RWA-related problems in waveband-switching networks arise which need to be identi ed and solved in order to optimize the performance of WBS networks. Let us rst concentrate on WBS networks without wavelength conversion.

Apart from routing and wavelength assignment, tunnel assignment is another important problem encountered in WBS networks, leading to the so-called routing and wavelength/tunnel assignment (RWTA) problem. The RWTA problem was investigated in Ho and Mouftah (2001). A tunnel is de ned as a group of consecutive wavelength channels grouped and switched together.

A tunnel can be either a waveband or ber tunnel. A waveband tunnel contains multiple consecutive wavelengths. A ber tunnel consists of multiple waveband tunnels.

The RWTA problem deals with the bundling and switching of consecutive wavelengths or wavebands as a waveband tunnel or ber tunnel, respectively, and routing lightpaths through them. Rules for allocating tunnels in mesh WBS networks were provided and studied in Ho and Mouftah (2001). Those rules recommend to use existing ber tunnels and waveband tunnels for lightpath set-up.

If no appropriate tunnels exist, it is recommended to give priority to creating a new ber tunnel over creating new waveband tunnels. If neither ber tunnels nor waveband tunnels can be newly established, the requested lightpath is set up without any tunnels by solving the conventional RWA problem. An ef cient approach to routing and wavelength assignment in mesh WBS networks with ber, waveband, and wavelength switching capabilities was presented in Lee et al.

(2004). The authors refer to this problem as the RWA+ problem. The RWA+ problem is formulated as a combinatorial optimization problem with the objective to minimize the bottleneck link utilization of mesh WBS networks.

The obtained results show that the proposed optimization approach outperforms conventional linear programming approaches in both accuracy and computational time complexity particularly for larger WBS networks. The so-called routing, wavelength assignment, and waveband assignment (RWWBA) problem was investigated in Li and Ramamurthy (2006). The RWWBA problem addresses the optimal routing and wavelength/waveband assignment in mesh WDM networks that deploy both wavelength switching and waveband switching.

The RWWBA problem aims at maximizing cost savings and minimizing blocking probability. To solve the RWWBA problem, the online integrated intermediate waveband switching algorithm was proposed which controls the creation of new waveband routes and determines the waveband grouping node and waveband disaggregating node along the selected route. Several other routing and wavelength assignment heuristics to minimize the ports needed at MG-OXCs in WBS networks for a given set of lightpath requests were proposed in Cao et al.

(2003c). The obtained results show that WBS is particularly bene cial in multi ber networks (i.e.

, networks where a link consists of multiple bers. Optical wide area networks in paralle Code 128 Code Set C for Java l). It was shown that using MG-OXCs can save up to 50% of ports in single- ber networks and up to 70% of ports in multi ber networks compared with using ordinary single-granularity OXCs that perform conventional wavelength switching. Next, let us consider the routing and wavelength/waveband assignment in WBS networks that make use of wavelength conversion.

The aforementioned RWTA problem was re-visited in Ho and Mouftah (2002) under the assumption that ordinary OXCs are able to perform full-range wavelength conversion. Due to the added wavelength converting capability, WBS networks become more exible and able to adapt better to given traf c demands, resulting in an increased utilization of waveband and ber tunnels. Apart from full-range wavelength conversion, the impact of various other types of wavelength conversion on the blocking probability of WBS networks was examined in Cao et al.

(2004b). Besides full-range and limited-range wavelength conversion, the so-called intraband wavelength conversion was studied which can be applied in practical WBS networks. With intraband wavelength conversion, a wavelength can only be converted to any other wavelength within the same waveband.

For example, let us assume that waveband b1 contains wavelengths w1 , w2 , w3 , and waveband b2 contains wavelengths w4 , w5 , w6 . Then wavelength w3 can only be converted to wavelengths w1 or w2 but not to wavelengths w4 , w5 , w6 . Note that intraband wavelength conversion differs from limited-range conversion in that it introduces an additional constraint by allowing wavelength conversion take place only within a given waveband.

The proposed wavelength assignment heuristic is able to reduce the blocking probability by ef ciently grouping wavelengths into wavebands and reducing the number of used wavelength converters when satisfying a new lightpath request. The special case of limited-range wavelength conversion was addressed in greater detail in Cao et al. (2005).

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