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In this paper, we propose an architecture of Optical Burst Switched WDM ring network. In our proposed OBS ring network, every node is equipped with one tunable transmitter and one fixed-tuned receiver (TTFR) oparating on a given wavelength that identifies the node. TTFR type ring network has an advantage that no receiver collisions occur and each node can detect channel collision by transmitter side. By computer simulations, we evaluate the performance of throughput, goodput, and queueing delay. As a result, we show the performance effectiveness of our proposed architecture and access protocol.

In this paper we consider how the performance of wavelength routed networks depends on node capabilities, such as the wavelength selection and the wavelength conversion. For this purpose we propose a modified version of the shortest path algorithm for the wavelength graph (SPAWG), where “virtual links” are added for modeling the utilization and the cost of these node capabilities.

Numerical results show the performance advantages in utilizing wavelength selection instead of wavelength conversion, when only one of the two capabilities can be implemented in each network node. When wavelength conversion and wavelength selection utilization is limited to a subset of network nodes to reduce the overall network cost, results indicate that sparse wavelength selection is not as beneficial as sparse wavelength conversion.

The paper proposes a general approach to support the analysis and evaluation of dynamic routing and wavelength assignment strategies applicable in advanced optical networks. Some ILP based models are introduced to apply the proposed analysis support for the evaluation of Separate Wavelength Pool strategy. Results from a small network example are described and analyzed to validate the proposed ILP models in one hand and to highlight the advantages of the shared capacity related resilience and the pre-emption techniques applicable in advanced optical networks on the other hand.

A promising approach to the effective utilization of wavelength division multi-plexed networks is to transfer data on an on-demand basis using fast wavelength reservation. Data can then be transferred using the assigned wavelength channel. However, if wavelength reservation fails, the lightpath setup delay, which is defined as the time from when the data-transfer request arises at the source node to when the lightpath between the source-destination pair is successfully established, is seriously affected since retrials of wavelength reservation are in turn delayed by propagation delays. In this paper, we propose a new wavelength reservation method to reduce lightpath setup delay. Whereas conventional methods reserve a wavelength in either the forward or backward direction, we propose to reserve it in both directions. We used computer simulations to compare our proposed method with existing methods. The results showed that our method was more efficient except under high traffic loads.

In this paper we incorporate the rerouting of backup paths to the Call Admission Control algorithm of Sub-Graph Routing Protection (SGRP). Sub-Graph Routing Protection with On-Arrival Planning (SGRP-OAP) has the two-fold benefit of strongly reducing the blocking probability of the protected system while eliminating the physical rerouting of established connections, which is a major drawback of the original proposal of SGRP. The new scheme is so capacity-efficient that, for all investigated topologies, at low traffic intensity the blocking probability of the system protected against single link failures is the same as the blocking probability of the unprotected system. This is possible because the new protection scheme is extremely effective in using the idle network capacity to provide backup paths.

We consider the routing and the wavelength assignment (RWA) of scheduled and random lightpath demands in a wavelength switching mesh network without wavelength conversion functionality. Scheduled lightpath demands (SLDs) are connection demands for which the set-up and tear-down times are known in advance as opposed to random lightpath demands (RLDs) which are dynamically established and released according to a random pattern of requests. Two routing strategies are proposed which process the SLDs and the RLDs separately. The first routing strategy allows to bifurcate the traffic on several routes connecting the source to the destination of a demand whereas the second strategy forces atomic routing. The routing strategies are compared through rejection ratio.

The paper presents efficient algorithms for routing and wavelength assignment for dynamic lightpath establishment as well as bandwidth guaranteed path protection against single link failure in a WDM mesh network. Several protection strategies for multi-wavelength optical network have been studied to indicate their relative efficiency in terms of network blocking probability performance and resource requirement. Protection results in integrated routing scenario are also presented.

Dynamic optical networks which are protected by -cycles can be operated by different -cycle configuration methods. We compare the blocking probability of two dynamic -cycle configuration approaches and one static -cycle configuration approach (protected working capacity envelope).

The accelerating growth of Internet traffic, together with its bursty traffic pattern is specially motivating the research on not only high-bandwidth but also dynamic metropolitan networks based upon recent advances in optical networking technologies such as R-OADM and OXC. The dynamism of the wavelength-routed networks can be achieved by means of a distributed control plane (i.e signalling for wavelength reservation and routing for dissemination of topology and optical resource state), which can be based in GMPLS. The objective of this paper is to propose a GMPLS-based signalling protocol which allows to have a global wavelength resource information without any routing protocol when provisioning bidirectional connections in uni-ring-based MAN. Performance evaluation has been carried in a GMPLS test-bed composed of Linux routers named ADRENALINE.

We propose a session-uninterrupted disaster recovery system using a novel session migration technique as a GMPLS application. Existing disaster recovery systems have a problem of a service interruption. The session migration based on an interlayer control of GMPLS, VLAN change-over, and process migration, maintains continuous TCP service between a user and a virtualized server, even when the service migrates from a primary data center to a backup one. We developed a prototype system and showed that BoD (bandwidth on demand) by GMPLS improved the recovery time from 80.10 sec to 9.85 sec, during transmitting a process data of 40MByte.