Neal Charbonneau

A Survey of Advance Reservation Routing and Wavelength Assignment in Wavelength-Routed WDM Networks

Traditionally, research on routing and wavelength assignment over wavelength-routed WDM networks is concerned with immediate reservation (IR) demands. An IR demand typically does not specify a holding time for data transmission and the start time of the data transmission is assumed to be immediate (i.e. when the connection request arrives). The concept of advance reservation (AR) has recently been gaining attention for optical networks. An AR demand typically specifies information about the start of the data transmission or a deadline, as well as the holding time of the transmission. AR has several important applications for both wide-area networks and Grid networks. For example, AR can be used for adjusting virtual topologies to adapt to predictable peak hour traffic usage. It can be used to provide high-bandwidth services such as video conferencing and in Grid applications requiring the scheduled distribution of large files and for co-allocation of network and grid resources. AR can also be beneficial to the network by allowing the network operator to better plan resource usage and therefore increase utilization. Knowledge of the holding time can lead to more optimal decisions for resource allocation. This translates to better quality of service for users. In this paper we provide a comprehensive survey of the past and current work on advance reservation for optical networks. There have been many variations of the advance reservation concept proposed, so we will also provide a broad classification. In addition to the survey, we will discuss what we believe are important areas of future work and open challenges for advance reservation on optical networks.

Static routing and wavelength assignment for multicast advance reservation in all-optical wavelength-routed WDM networks

In this paper, we investigate the static multicast advance reservation (MCAR) problem for all-optical wavelength-routed WDM networks. Under the advanced reservation traffic model, connection requests specify their start time to be some time in the future and also specify their holding times. We investigate the static MCAR problem where the set of advance reservation requests is known ahead of time. We prove the MCAR problem is NP-complete, formulate the problem mathematically as an integer linear program (ILP), and develop three efficient heuristics, seqRWA, ISH, and SA, to solve the problem for practical size networks. We also introduce a theoretical lower bound on the number of wavelengths required. To evaluate our heuristics, we first compare their performances to the ILP for small networks, and then simulate them over real-world, large-scale networks. We find the SA heuristic provides close to optimal results compared to the ILP for our smaller networks, and up to a 33% improvement over seqRWA and up to a 22% improvement over ISH on realistic networks. SA provides, on average, solutions 1.5-1.8 times the cost given by our conservative lower bound on large networks.

Routing and Wavelength Assignment of Static Manycast Demands Over All-Optical Wavelength-Routed WDM Networks

In this paper we present the static manycast routing and wavelength assignment (MA-RWA) problem along with heuristics and an integer linear program (ILP) to solve it. Manycast is a point-to-multipoint communication paradigm with applications in e-Science, Grid, and cloud computing. A manycast request specifies a candidate set of destinations, of which a subset must be reached. To solve MA-RWA, a light-tree must be assigned to each manycast request in a static set such that the number of wavelengths required is minimized. We present two heuristics, the shortest path heuristic (SPT) and the lambda path heuristic (LPH), a tabu search meta-heuristic (TS), and an ILP formulation. We show that TS provides results close to the optimal solution (from the ILP) for small networks. We then show that TS provides a 10% improvement over LPH and a 30%-40% improvement over SPT for various realistic networks.

Advance reservation frameworks in hybrid IP-WDM networks

New e-Science and grid applications require the coordination of geographically distributed scientific instruments along with data and computing resources. Due to the quality of service requirements of these applications, these distributed resources can be connected by a wavelength-routed optical network, allowing each application to get dedicated bandwidth. These networks are referred to as LambdaGrids. One important service provided in these networks is advance reservation. Applications need to coordinate the use of both grid resources and the network. Advance reservation allows these applications to reserve bandwidth in advance to guarantee availability. In this article, we discuss different networks and frameworks that support advance reservation of bandwidth. We discuss the general architecture of each network and the type of advance reservation services supported.

Tabu Search Meta-Heuristic for Static Manycast Routing and Wavelength Assignment over Wavelength-Routed Optical WDM Networks

This paper presents a tabu search meta-heuristic to solve the static manycast routing and wavelength assignment problem (MA-RWA). The problem is to route a set of manycast requests over a wavelength-routed WDM network such that the number of wavelengths required is minimized. We present the details of a tabu search meta-heuristic for this problem and compare it to two other MA-RWA heuristics called lambda path heuristic (LPH) and shortest path tree (SPT) heuristic. The tabu search meta-heuristic shows a 10% improvement over LPH and a 30-40% improvement over SPT for various realistic networks.

Source-ordering for improved TCP performance over load-balanced optical burst-switched (OBS) networks

Recent advances in optical switching technology allow for the creation of networks in which data bursts are switched optically at each node, offering a greater degree of flexibility suitable for handling bursty Internet traffic. TCP-based applications account for a majority of data traffic in the Internet; thus understanding and improving the performance of TCP implementations over OBS networks are critical. Previously, several articles show that load-balanced routing improves loss-performance in OBS. In this paper, we identify the ill-effects of load-balanced OBS on TCP performance caused by false time-outs and false fast-retransmits. We propose a source-ordering mechanism that significantly improves TCP throughput over a load-balanced OBS network.

Dynamic circuits with lightpath switching over wavelength routed networks

In this paper we examine provisioning holding-time-aware dynamic circuits using a technique called lightpath switching (LPS). Instead of using the same lightpath for the duration of the data transmission, in LPS we allow a request to switch lightpaths over time. Data transmission may begin on one lightpath from the source to destination, then at a later time a different lightpath from the source to the destination may be selected to continue data transmission. The lightpath switches are transparent to the user and are managed by the network. Allowing LPS creates a number of segments that can use independent lightpaths. We compare the performance of traditional routing and wavelength (RWA) assignment to routing and wavelength assignment with LPS. We show that LPS can significantly reduce blocking compared to traditional RWA. 1

Dynamic circuit provisioning in all-optical WDM networks using lightpath switching ✩

Abstract In this paper we investigate the problem of provisioning holding-time-aware (HTA) dynamic circuits in all-optical wavelength division multiplexed (WDM) networks. We employ a technique called lightpath switching (LPS) wherein the data transmission may begin on one lightpath and switch to a different lightpath at a later time. Lightpath switches are transparent to the user and are managed by the network. Allowing LPS creates a number of segments that can use independent lightpaths. We first compare the performance of traditional routing and wavelength (RWA) assignment to routing and wavelength assignment with LPS. We show that LPS can significantly reduce blocking compared to traditional RWA. We then address the problem of routing dynamic anycast HTA dynamic circuits. We propose two heuristics to solve the anycast RWA problem: anycast with continuous segment (ACS) and anycast with lightpath switching (ALPS). In ALPS we exercise LPS, and provision a connection request by searching for the best candidate destination node is such a way that the network resources are utilized efficiently. In ACS we do not allow a connection request to switch lightpaths. The lightpaths to each candidate destination node of a request are computed using traditional RWA algorithms. We first compare the performance of ACS to ALPS and observe that ALPS achieves better blocking than ACS. Furthermore, we also compare the performance of these two anycast RWA algorithms to the traditional unicast RWA algorithm. We show that the anycast RWA algorithms presented here significantly outperform the traditional unicast RWA algorithms.

Performance modeling of HS-RR-TCP over load-balanced optical burst-switched (OBS) networks

TCP-over-OBS is a promising transport paradigm to support next-generation Internet. It is well known that load-balanced routing generally improves loss performance over OBS. We identify that implementing TCP over load-balanced OBS could lead to persistent out-of-order delivery of TCP segments, resulting in unnecessary timeouts and fast retransmissions. In this paper we evaluate the performance of Reordering-Robust TCP (RR-TCP) over OBS networks. We develop an analytical end-to-end transfer delay model for TCP SACK and RR-TCP over load-balanced OBS networks. We observe that standard TCP experiences significant throughput degradation due to persistent packet reordering. Through simulations and modeling we show that RR-TCP achieves significant improvement compared to TCP SACK. In our simulations we add High-Speed TCP functionality to RR-TCP (HS-RR-TCP). The simulations show up to a 300% performance improvement for HS-RR-TCP compared to HS-TCP-SACK under ideal conditions and a 20% improvement on NSFnet with background traffic.

Static manycast routing and wavelength assignment over wavelength-routed optical WDM networks

We present our initial work for static manycast routing and wavelength assignment (MA-RWA) over wavelength-routed optical WDM networks. The goal is to route a set of static manycast requests over a wavelength-routed WDM network while minimizing the number of wavelengths required. This is the first time the problem has been investigated. We present a lambda path heuristic (LPH) to solve the MA-RWA problem and compare it to a simple shortest path manycast heuristic. LPH achieves a 20–30% improvement in required wavelengths over realistic networks.