Traffic Grooming Algorithm Using Shortest EDPs Table in WDM Mesh Networks

In wavelength-division multiplexing (WDM) optical networks, the bandwidth request of a traffic stream can be much lower than the capacity of a lightpath. Efficiently grooming low-speed connections onto high-capacity lightpaths will improve the network throughput and reduce the network cost. In WDM/SONET ring networks, it has been shown in the optical network literature that by carefully grooming the low-speed connection and using wavelength-division multiplexer (OADM) to perform the optical bypass at intermediate nodes, electronic ADMs can be saved and network cost will be reduced. In this study, we investigate the traffic-grooming problem in a WDM-based optical mesh topology network. Our objective is to improve the network throughput. We study the node architecture for a WDM mesh network with traffic-grooming capability. A mathematical formulation of the traffic-grooming problem is presented in this study and several fast heuristics are also proposed and evaluated.

A novel robust routing algorithm for multi-granularity connection requests in wavelength division multiplexing mesh networks

In wavelength division multiplexing (WDM) mesh networks, wavelength utilization is limited by the mismatch between the high bandwidth that one wavelength can provide and the relatively low bandwidth request of a single connection. Traffic grooming which grooms multiple connections onto one wavelength is a desirable technique to improve resource utilization. However, with unpredictable traffic demand, the newly arrived request may not be accommodated using remaining resources. Rerouting which reroutes existing connections such that the newly arrived request can be accommodated is an effective approach to further improve network throughput. In this paper, we study adaptive intentional connection rerouting which intentionally triggers rerouting algorithm according to network status, with the aim to reserve maximum resources for future connections. There are two important issues in intentional rerouting scheme: when to trigger rerouting algorithm and the rule to reroute the accommodated connections. The answers to the questions can reduce network blocking probability within an appropriate number of rerouting. In this paper, we propose to use biological attractor selection approach to address the above issues so that rerouting can be performed at the right time to accommodate unpredictable traffic demand. The proposed rerouting scheme can also improve system robustness given its adaptability. The simulations demonstrate the effectiveness of our proposed adaptive rerouting approach.

In wavelength-division multiplexing (WDM) optical networks, the bandwidth request of a traffic stream can be much lower than the capacity of a lightpath. Therefore, to utilize the network resources (such as bandwidth and transceivers) effectively, several low-speed traffic streams can be efficiently groomed or multiplexed into high-speed lightpaths, thus we can improve the network throughput and reduce the network cost. Traffic grooming can be considered separately at each individual node based on only local information (local grooming), or in cooperation between nodes participating in grooming (global grooming). In the second case, nodes must exchange their information about available resources and grooming strategies. The grooming problem of a static demand is considered as an optimization problem. In this work, we have proposed a traffic grooming algorithm to maximize the network throughput for wavelength-routed mesh networks. The efficiency of our approach has been established through extensive simulation on different sets of traffic demands with different bandwidth granularities for different network topologies and compared the approach with existing algorithm.

To utilize the wavelength resources of Internet protocol (IP) over wavelength division multiplexing (WDM) optical networks, a multi-constrained multicast traffic grooming algorithm is proposed in this paper. This algorithm can achieve multicast traffic grooming in IP over WDM optical networks under multi-constraints, including the number of optical transceivers, wavelength conversion capability and wavelength splitting capability. We simulated the traffic grooming algorithm using the topology of GEANT. Emulation results show that our algorithm has a lower blocking proportion compared with the multi-hop traffic grooming algorithm, which can achieve multicast traffic grooming more effectively.

With the increasing diversity of applications supported over optical networks, new service guarantees must be offered to network customers. Among the emerging data-intensive applications are those which require their data to be transferred before a predefined deadline. We call these deadline-driven requests (DDRs). In such applications, data-transfer finish time (which must be accomplished before the deadline) is the key service guarantee that the customer wants. In fact, the amount of bandwidth allocated to transfer a request is not a concern for the customer as long as its service deadline is met. Hence, the service provider can choose the bandwidth (transmission rate) to provision the request. In this case, even though DDRs impose a deadline constraint, they provide scheduling flexibility for the service provider since it can choose the transmission rate while achieving two objectives: 1) satisfying the guaranteed deadline; and 2) optimizing the network's resource utilization. We investigate the problem of provisioning DDRs with flexible transmission rates in wavelength-division multiplexing (WDM) mesh networks, although this approach is generalizable to other networks also. We investigate several (fixed and adaptive to network state) bandwidth-allocation policies and study the benefit of allowing dynamic bandwidth adjustment, which is found to generally improve network performance. We show that the performance of the bandwidth-allocation algorithms depends on the DDR traffic distribution and on the node architecture and its parameters. In addition, we develop a mathematical formulation for our problem as a mixed integer linear program (MILP), which allows choosing flexible transmission rates and provides a lower bound for our provisioning algorithms.

As the energy consumption of network has become an increasingly important issue, traffic grooming on Internet protocol over wavelength division multiplexing (IP-WDM) networks has been widely used for energy-efficient optical network. Traffic grooming can reduce the number of installed light paths and corresponding IP router line cards at the cost of traffic processing overhead. However, traditional traffic grooming algorithm prefers longer paths, which are responsible for longer transmission hop distance. Although there are studies that focus on reducing hop distance, the energy consumption increases accordingly. In this way, the trade-off between energy consumption and hop distance is a problem worth discussing. This paper proposes a modified heuristic traffic grooming algorithm which can improve the trade-off efficiency by about 20%, compared with the earlier algorithms.

In general, multicast routing and wavelength assignment (MC-RWA) can be subdivided in routing and wavelength assignment issues in wavelength-division multiplexing (WDM) mesh networks. Previous studies on WDM multicast have mainly focused on WDM multicast routing. The multicast wavelength assignment problem is studied in this paper. A unicast routing path can be established by a lightpath in an all-optical network. However, in the multicasting case, a multicast routing tree can be established by a single light-tree or several lightpaths, or a combination of several light-trees and lightpaths. We propose a wavelength assignment algorithm for finding an optimal combination of lightpaths and light-trees to construct a newly required multicast session. First of all, two cost functions are given to evaluate the establishing cost for each feasible wavelength, and then find a set of wavelengths that covers all destinations with the minimal cost using Integer Linear Programming (ILP) formulation. We focus on maximizing the total number of users served in a multicast session and the network capacity. The simulation results show that the proposed algorithm can improve system resource utilization and reduce the blocking probability compared with the First-Fit algorithm.

This paper investigates the problem of dynamically establishing dependable connections in traffic-grooming wavelength division multiplexing (WDM) mesh networks, and proposes a dynamic shared sub-path protection (SSPP) scheme for multi-granularity traffic. To establish a dependable connection, SSPP searches a primary path for each connection request, and then it segments the found path into several equal-length sub-paths, and computes their corresponding backup paths, respectively. In SSPP, if two sub-paths are fiber-disjoint then their backup paths can share backup resources to obtain the optimal spare capacity. Based on dynamic traffic with different load, the performance of SSPP has been investigated via simulations. The results show that SSPP can make the tradeoffs between the resource utilization and the restoration time.

In this paper, we investigate the problem of survivable grooming for anycasting over wavelength division multiplexing (WDM) networks. Anycasting is a communication paradigm in which a source node sends data to any one out of multiple candidate destinations. In WDM networks, the standard anycasting problem involves the establishment of a connection from the source to any one destination with the objective of minimizing the resources used. In order to provide survivability, the problem can be extended to find both a connection to a primary destination and a connection to a backup destination. The connections, which may require an amount of bandwidth that may be less than the bandwidth of an entire wavelength, can be groomed with other connections in the WDM network. We propose an auxiliary graph approach to solving the survivable grooming problem for anycasting in WDM networks, and we propose three different protection approaches for providing different degrees of survivability against link failures and destination failures. The effectiveness of the proposed schemes is verified through simulation.

We investigate waveband switching (WBS) with different grouping strategies in wavelength-division multiplexing (WDM) mesh networks. End-to-end waveband switching (ETE-WBS) and same-destination-intermediate waveband switching (SD-IT-WBS) are analyzed and compared in terms of blocking probability and cost savings. First, an analytical model for ETE-WBS is proposed to determine the network blocking probability in a mesh network. For SD-IT-WBS, a simple waveband switching algorithm is presented. An analytical model to determine the network blocking probability is proposed for SD-IT-WBS based on the algorithm. The analytical results are validated by comparing with simulation results. Both results match well and show that ETE-WBS slightly outperforms SD-IT-WBS in terms of blocking probability. On the other hand, simulation results show that SD-IT-WBS outperforms ETE-WBS in terms of cost savings.

Recent development in optical networking employing wavelength division multiplexing (WDM) fulfills the high bandwidth demand applications. Failure of such networks, leads to enormous data and revenue loss. Protection is one of the key techniques, which is used in designing survivable WDM networks. In this paper we compare dedicated and shared protection strategies employed inWDMmesh networks to protect optical networks failure, particularly fiber failure. Dijkstra’s shortest path algorithm is considered for carrying out simulations. The paper compares the performance of protection schemes, such as, dedicated path protection (DPP), shared path protection (SPP) and shared link protection (SLP) schemes. Capacity utilization, switching time and blocking probability are the parameters considered to measure the performance of the protection schemes. Simulation results show that, SPP is more efficient in terms of capacity utilization over DPP and SLP schemes, whereas, SLP offered better switching time than both DPP and SPP schemes. The average call drop rate is minimum for shared path protection scheme and maximum for shared link protection scheme.

This paper studies a traffic grooming in wavelength-division multiplexing (WDM) mesh networks for the SONET/SDH streams requested between node pairs. The traffic could be groomed at the access node before converting to an optical signal carried in the all-optical network. We design a virtual topology with a given physical topology to satisfy multiple objectives and constraints. The grooming problem of a static demand is considered as an optimization problem. The algorithms found in the literatures focus on a single objective either to maximize the performance or to minimize the cost. We propose a multiobjective evolutionary algorithm to solve a grooming problem that optimizes multiple objectives all together at the same time. In this paper we consider the optimization of three objectives: maximize the traffic throughput, minimize the number of transceivers, and minimize the average propagation delay or average hop counts. The simulation results show that our approach is superior to an existing heuristic approaches for the 6-node benchmark network in an acceptable running time.

In this paper, we propose novel traffic grooming algorithms to reduce the cost of the entire system in WDM multi-ring networks. In order to achieve this goal, it is important to construct a virtual topology and groom the traffic in these networks. We consider four kinds of virtual topologies of WDM multi-ring networks according to the way in which traffic is transmitted among rings. Accordingly, we design four kinds of traffic grooming (TG) algorithms depending on the considered virtual topologies: mixed (MTG), partially mixed (PMTG), separate (STG), and independent (ITG) traffic grooming algorithms. Each algorithm consists of a separation, a connection-ring construction, and a grooming procedure. In the separation procedure, all traffic connections are classified into intra and inter-connections. The connection-ring construction procedure makes full connection-rings from traffic connections. The grooming procedure groups connection-rings onto a wavelength in order to reduce the number of SONET add/drop multiplexers (SADMs) and wavelengths and to improve the utilization of network resources. To analyze the performance of each algorithm, a circular multi-ring architecture with uniform traffic is considered. The simulation results show that ITG and PMTG are more efficient in terms of wavelengths. STG and PMTG require a smaller number of SADMs.

Routing and wavelength assignment (RWA) problem is an important issue in optical transport networks based on wavelength division multiplexing (WDM) technique. It is typically solved using a combination of linear programming and graph coloring, or path selection based graph algorithms. Such methods are either complex or make extensive use of heuristics. In this paper we propose a novel and efficient approach which basically obtains the maximum edge disjoint paths (EDPs) for each source-destination demand pair. And those EDPs obtained are stored in Lookup Table and used for the update of weight matrix. Routes are determined in order by the weight matrix for the demand set. The comprehensive computer simulation shows that the proposed algorithm uses similar or fewer number of wavelengths with significantly less execution time than bounded greedy approach (BGA) for EDP [2] which is currently known to be effective in practice.KeywordsOptical NetworkWavelength Division MultiplexLookup TableWavelength AssignmentWavelength ConverterThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.