Performance of TCP over ABR on ATM backbone and with various VBR traffic patterns

We extend our earlier studies of bu er requirements of TCP over ABR [10, 11, 12] in two directions. First, we study the performance of TCP over ABR in an ATM backbone. On the backbone, the TCP queues are at the edge router and not inside the ATM network. The router requires bu er equal to the sum of the receiver window sizes of the participating TCP connections. Second, we introduce various patterns of VBR background tra c. The VBR background introduces variance in the ABR capacity and the TCP tra c introduces variance in the ABR demand. Some simple switch schemes are unable to keep up with the combined e ect of highly varying demands and highly varying ABR capacity. We present our experiences with re ning the ERICA+ switch scheme to handle these conditions.