Adaptive routing in ad hoc wireless multi-hop networks

Ad hoc wireless multi-hop networks (AHWMNs) are communication networks that consist entirely of wireless nodes, placed together in an ad hoc manner, i.e. with minimal prior planning. All nodes have routing capabilities, and forward data packets for other nodes in multi-hop fashion. Nodes can enter or leave the network at any time, and may be mobile, so that the network topology continuously experiences alterations during deployment. AHWMNs pose substantially different challenges to networking protocols than more traditional wired networks. These challenges arise from the dynamic and unplanned nature of these networks, from the inherent unreliability of wireless communication, from the limited resources available in terms of bandwidth, processing capacity, etc., and from the possibly large scale of these networks. Due to these different challenges, new algorithms are needed at all layers of the network protocol stack. We investigate the issue of adaptive routing in AHWMNs, using ideas from artificial intelligence (AI). Our main source of inspiration is the field of Ant Colony Optimization (ACO). This is a branch of AI that takes its inspiration from the behavior of ants in nature. ACO has been applied to a wide range of different problems, often giving state-of-the-art results. The application of ACO to the problem of routing in AHWMNs is interesting because ACO algorithms tend to provide properties such as adaptivity and robustness, which are needed to deal with the challenges present in AHWMNs. On the other hand, the field of AHWMNs forms an interesting new application domain in which the ideas of ACO can be tested and improved. In particular, we investigate the combination of ACO mechanisms with other techniques from AI to get a powerful algorithm for the problem at hand. We present the AntHocNet routing algorithm, which combines ideas from ACO routing with techniques from dynamic programming and other mechanisms taken from more traditional routing algorithms. The algorithm has a hybrid architecture, combining both reactive and proactive mechanisms. Through a series of simulation tests, we show that for a wide range of different environments and performance metrics, AntHocNet can outperform important reference algorithms in the research area. We provide an extensive investigation of the internal working of the algorithm, and we also carry out a detailed simulation study in a realistic urban environment. Finally, we discuss the implementation of ACO routing algorithms in a real world testbed

Survivable routing in IP-over-WDM networks: An efficient and scalable local search algorithm

In IP-over-WDM networks, a logical IP network is routed on top of a physical optical fiber network. An important challenge hereby is to make the routing survivable. We call a routing survivable if the connectivity of the logical network is guaranteed in case of a failure in the physical network. In this paper we describe FastSurv, a local search algorithm for survivable routing. The algorithm works in an iterative manner: after each iteration it learns more about the structure of the logical graph and in the next iteration it uses this information to improve its solution. The algorithm can take link capacity constraints into account and can be extended to deal with multiple simultaneous link failures and node failures. In a large series of tests we compare FastSurv with current state-of-the-art algorithms for this problem. We show that it can provide better solutions in much shorter time, and that it is more scalable with respect to the number of nodes, both in terms of solution quality and run time

Università della Svizzera italiana Faculty of Informatics Adaptive Routing in Ad Hoc Wireless Multi-hop Networks

by the Future & Emerging Technologies unit of the European Commission through project “BISON: Biology-Inspired techniques for Self Organization in dynamic Networks ” (IST-2001-38923) an

Fastsurv: A new efficient local search algorithm for survivable routing in WDM networks

Abstract — In IP-over-WDM networks, a logical IP network has to be routed on top of a physical optical fiber network. An important challenge is to make this routing survivable. We call a routing survivable if no single physical link failure can disconnect the logical topology. In this paper we present FastSurv, a local search algorithm for survivable routing. FastSurv works in an iterated way: after each iteration it learns more about the structure of the logical graph and in the next iteration it uses this information to improve its solution. We also extend the algorithm to take link capacity constraints into account. We show that our simple algorithm can produce better and faster results than current state-of-the-art algorithms. I

AntHocNet: an ant-based hybrid routing algorithm for mobile ad hoc networks

Abstract. In this paper we present AntHocNet, a new algorithm for routing in mobile ad hoc networks. Due to the ever changing topology and limited bandwidth it is very hard to establish and maintain good routes in such networks. Especially reliability and efficiency are important concerns. AntHocNet is based on ideas from Ant Colony Optimization. It consists of both reactive and proactive components. In a reactive path setup phase, multiple paths are set up between the source and destination of a data session, and during the course of the communication session, ants proactively test existing paths and explore new ones. In simulation tests we show that AntHocNet can outperform AODV, one of the most important current state-of-the-art algorithms, both in terms of end-to-end delay and packet delivery ratio.

A scalable algorithm for survivable routing in IP-over-WDM networks

In IP-over-WDM networks, a logical IP network has to be routed on top of a physical optical fiber network. An important challenge hereby is to make the routing survivable. We call a routing survivable if the connectivity of the logical network is guaranteed in case of a failure in the physical network. In this paper we describe FastSurv, a local search algorithm which can provide survivable routing in the presence of physical link failures. The algorithm can easily be extended for the case of node failures and multiple simultaneous link failures. In a large series of test runs, we show that FastSurv is much more scalable with respect to the number of nodes in the network than current state-of-the-art algorithms, both in terms of solution quality and run time