PICCO: Protocol Independent Congestion Control Method Using Mobile Relays for Ad-Hoc Networks

Abstract

The limited lifetime of batteries and the bandwidth limitation of channels are the major issues in Ad-hoc networks. The term Congestion is usually associated with the bandwidth issues. The bandwidth keeps varying and when there is insufficient bandwidth to satisfy the demand, we say we have a congestion problem. Congestion control methods are partially implemented in the network elements (e.g.: routers) inside the network and partially in the transport protocols running on the end hosts. All congestion control methods were developed depending on the underlying transport protocol TCP and hence cannot be used when the underlying transport protocol changes to UDP. In real time applications, where UDP is mostly used with Real time Transport Protocol (RTP), lost data packets cannot be resent. So it becomes all the more critical to have a proper congestion control method which can be used by UDP as well. PICCO method to solve the congestion problem can be implemented only in the network elements and is independent of the underlying transport protocols. Hence it can be used for TCP as well as UDP. This method reduces the number of packets being dropped in the network, thus improving the overall performance of the network.