Network Congestion Management and the Mobile Agent Paradigm

Congestion management (avoidance and control) is a set of mechanisms used to prevent network congestion and assist in the recovery from it. The constant growth of the Internet many congestion control mechanisms have been proposed and some of them implemented on the global Net. Most modifications to the original TCP protocol have faired rather well and have preserved the scalability and the stability of the Internet. The emergence of bandwidth intensive multimedia applications and the usage of UDP have proved that the existing congestion control mechanisms are not sufficient to prevent the network from exhaustion of its resources and possible congestion collapse. Multimedia applications often generate traffic flows that are unresponsive to network congestion. Consequently, the packets are not delivered to their destinations since they are being dropped at the intermediate nodes. In other words, transmitting unresponsive flows through a network is one of the main reasons behind possible network collapse, since the potential of the network is fully utilized, while too few packets reach the intended recipients. It is clear that the congestion management of unresponsive flows in presence of both responsive flows and unresponsive flows is an open problem. The paper describes the study into the possibility to use the mobile agent paradigm for management of mostly unresponsive flows and integrating this mechanism with the classical congestion control protocols in a pure TCP environment. To illustrate the main points of our position, we introduce a new model termed as CM4CC (Combined Model for Congestion Control).