Interactive buffer sizing for core routers

At present, buffer sizing for routers is generally based on the model of Transmission Control Protocol (TCP) on the transmission layer, ignoring the interaction of the network elements and having its connate limitation as for analyzing the performance for the routers on the network layer. How the routers interact in the network and how can we design the routers practically? From the perspective of the network layer, a new model, introducing the effects brought by each router, is proposed for a TCP link. By comparing the impact of access routers with the impact of core routers on link performance and analyzing the part of core routers with the separate method, a lower bound of required buffer size for an interface of a core router is deduced under given constraints on the maximum loss rate and minimum effective utilization. The simulation results validate the conclusion and also indicate this lower bound for buffer size is much looser than the actual lower bound. Our conclusion is a valuable instruction for practically designing buffer size for core routers.