Improved-AntNet: ACO routing algorithm in practice Satish Chandra, Utkarsh Shrivastava, Rajan Vaish, Siddharth Dixit, Manisha Rana Department of Computer Science & Information Technology Jaypee University of Information Technology, Solan, India Emails: satish.chandra@juit.ac.in, {utkarsh12, vaish.rajan , siddharthdixit1986, manisharana47}@gmail.com Abstract The objective of this paper is to introduce the Improved-Ant Colony Optimization in Virtual Circuit Networks. We discuss AntNet, an improved version of Ant Colony applied as a routing protocol. A new model is proposed that introduces the application of Ant Colony Optimization in the area of communication network. The proposed model is analyzed with the application of shortest path algorithm in Virtual Private Network. We also discuss the drawbacks of other optimization techniques that paved for the use of Ant Colony Optimization as an efficient optimization technique. In finding the optimal path, the proposed model is found to perform better than the OSPF. Keywords: Virtual circuit network, Routing, Ant Colony Optimization (ACO), OSPF, AntNet 1. Introduction The goal of every routing algorithm is to direct traffic from sources to destinations optimizing at the same time several measure of network performance as throughput (correctly delivered bits per time unit), packet delays and resources utilization. The general problem of determining an optimal routing algorithm can be stated as a multi objective optimization problem in a non-stationary stochastic environment. The AntNet for adaptive routing algorithms was proposed by Gianni di Caro and Marco Dorigo[16]. The design of this algorithms has been the inspired by ant colonies and, more generally, by the notion of stigmergy. Real ants have been shown to be able to find shortest paths using a stochastic decision policy based only on local information represented by the pheromone trail deposited by other ants [17].The goal of this research is to implement this behavior on a small virtual circuit network. In the next section we propose a model to improve ACO algorithm. In section 3, we present a modified version of the AntNet algorithm. Section 4, contains the results of some tests followed by conclusions. 2 Proposed Model We introduce I-ACO which is an improvement to the ACO algorithm introduced by Marco Dorigo[1]. AntNet is a routing protocol for packet switched networks, invented by M. Dorigo and G. Di Caro[2]. It is an alternative routing algorithm for the well-known OSPF protocol, based on Ant Colony Optimization (ACO). ACO studies the behavior of ants in a colony and mimics this behavior in software. The problem to be solved, is represented by a graph. Artificial agents, i.e. software ants, gradually construct paths in this graph. This phase is repeated until an optimal (or in some cases a sub-optimal) solution is found. ACO has been applied to many domains, e.g. the Traveling Salesmen Problem [3], manufacturing control systems, etc. A good overview of the ACO meta-heuristic and a number of applications can be found in [4].ACO itself is a metaheuristic. When combined with an actual problem area, it can lead to several heuristics. AntNet is a result of the application of ACO on the problem of Internet routing. Intelligent agents, ants for short, are sent over the network. They communicate indirectly by information they leave behind in the routers on their path. Over time, this information leads to optimal routing paths between the routers in the network. In a Virtual Circuit Network[5], the sender first attempts to create a “virtual circuit “to the receiver by sending a packet from the source to the destination using any shortest path algorithm ,following which all the packets travel through same path and thereby completing the traversal 2. The AntNet algorithm The operation of AntNet is based on two types of agents: UKSim 2009: 11th International Conference on Computer Modelling and Simulation 978-0-7695-3593-7/09 $25.00 © 2009 IEEE DOI 10.1109/UKSIM.2009.97 25