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In this implementation of AntNet-3.0 one could get the behavior of both algorithms through a simple

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

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 vis omnet.ini file.
In Router.cc, i have just catered for the service time due to queues and since omnetpp has the feature that if you 
queue two packets on a gate, the second packets get transmitted only after the first one. Due to this feature, the queuing
delay as measured by the implementation would be a little less as expected. Data packets and backward ants use different
queues but data packets do not wait for all the ants to be transmitted.

Future work: To implement a buffer class, in which both type of packets could be enqueud and data packets are
only transmitted once there are no backward ants for transmission. Though this would not drastically degrade the
performance, as compared to the current one.

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

In case of any problems please contact Muddassar Farooq [e-mail]