The current TCP or its variants are challenged with a number performance related issues when deployed in high Bandwidth-Delay Products, BDP, Networks such as the grid. Prominent among these challenging performance issues is poor network resource allocation which leads to under-utilisation of the grid. This thesis focuses on the development of a novel transmission control protocol which allocates network resource optimally whenever the Bandwidth-Delay Products are high typical in the grid. The thesis presents an congestion avoidance approach which is based on a link"s available bandwidth. To achieve the research goal, the problem of a link"s resource allocation, in high Bandwidth-Delay Products Networks, was analysed, defined and expressed as an optimisation problem with the link"s available bandwidth as a solution to the optimisation problem. To formulate an estimation scheme for the link"s available bandwidth, fluid mechanics and graph theory were employed. An algorithm was...