The model implements an Ant-based routing algorithms (AntNet-CL and AntNet-CO) proposed by G. Di Caro and M. Dorigo. This model version works with omnetpp 3.0a3 and up.

AntNet was proposed by Gianni Di Caro & Marco Dorigo in [1] . In AntNet the network state is monitored through two ant agents: Forward_Ant and Backward_Ant. A Forward_Ant agent is launched at regular intervals from a source to a certain destination. It uses the same queues as data packets to monitor the real traffic situation. Forward_Ant agent is equipped with a stack memory on which the address and entrance time of each node on its path are pushed. Once the Forward_Ant agent reaches its destination it creates a Backward_Ant agent and transfers all information to it. Backward_Ant visits the same nodes as Forward_Ant in reverse order and modifies the entries in the routing tables based on the trip time from the nodes to the destination. At each node the average trip time, the best trip time and the variance of the trip times for each destination are maintained. The trip time values are calculated by taking the difference of entrance times of two subsequent nodes pushed onto the stack. Backward_Ant agent uses the system priority queues so that it disseminates the information to the nodes as soon as possible.

However, the authors later on renamed AntNet as AntNet-CL and proposed another version of it in [2] namely AntNet-CO. AntNet-CO uses the concepts of flying ants in which forward moving Forward_Ant agent does not have to wait in the normal queues to determine the queuing delay rather they use an estimation model described in [2] to estimate the delay. Consequently, the routing information quickly spreads in the network.

In this implementation of AntNet one could get the behavior of both algorithms through a simple #define. The implementation has been tested and works with Windows XP and MSVC6.0 and Omnetpp3.0a3.

The steps are following:

1. Open protocolParameters.h file
2. Go to line 38 that has #define _FLYINGANTSbg
3. If you are interested in compiling AntNet-CL, then comment this line
4. If you are interested in compiling AntNet-CO, then simply remove the // from the beginning of this line.
5. Rest everything remains the same
6. Please ensure that Omnet++ is installed and all of its libararies and bin are in the path.
7. type ‘opp_nmakemake -u Cmdenv’ in the directory where you unzipped the antNet4.0.zip
8. type ‘nmake -f Makefile.vc depend’
9. type ‘nmake -f Makefile.vc’
10. Congratulations:) you have compiled the program.

In this implementation the most important files that are of interest are

1. AntNest.cc
2. Router.cc

In AntNest.cc, the handling forward and backward ants is implemented. I have tried to have implemented the concepts in this regard as discussed in [1]. The parameters that are of interest could be given via omnet.ini file. In Router.cc, i have just catered for the service time due to queues.

Enjoy working with AntNet and thanks to Gianni and Dorigo for the wonderful routing algrithm.

In case of any problems please contact Muddassar Farooq [email protected]

[1] G. Di Caro and M. Dorigo. AntNet: Distributed Stigmergetic Control for Communications Networks. Journal of Artificial Intelligence Research, 9:317–365, 1998

[2] G. Di Caro and M. Dorigo. Two ant colony algorithms for best-effort routing in datagram networks. In Y. Pan, S. G. Akl, and K. Li, editors, Proceedings of the Tenth IASTED International Conference on Parallel and Distributed Computing and Systems (PDCS’98), pages 541–546. IASTED/ACTA Press, Anheim, 1998.