Integrating disruption-prone links into reliable networks: a transmission control protocol friendly approach

Although progress has been made to satisfy mobility at the network´s edge, much work remains for deeper mobility requirements. In many emergency or military applications, fixed network infrastructure may not be available or even possible. As mobile military data requirements grow, and spectrum limitations increase, systems must better utilise the diminishing available bandwidth of wireless radio frequency and free space optical links. To achieve better utilisation, disruption-prone networks require disruption-tolerant protocols or localised buffering to mask disruptions. Transmission control protocol (TCP)/IP assumes reliable links and performs well in networks with congestion dominated packet losses, but poorly with link failure dominated packet losses. Although TCP might be altered for disruptive environments, evolutionary reasons make it difficult to do so well without partitioning networks into reliable and disruption-tolerant systems. Instead, the authors examine transport layer aware helper protocols, with intermediate buffering in routers, to assist TCP across disruption-prone network portions. The buffering does not require TCP modifications at communicating nodes and integrate well with existing routers (i.e. TCP friendly). Experimental results show that TCP can reliably establish and maintain connections under poor link availability using the buffering protocol. Few TCP connections complete without it.