Congestion control for LAN/MAN interconnection

We propose a congestion control scheme for interconnected networks where several local area networks (LANs) are connected to a high speed backbone network via gateways. In such a network, traffic congestion may occur due to the difference of transmission speed and/or workload between the high speed backbone and the lower speed LANs. For example, when several source gateways transmit packets destined to a destination gateway simultaneously, a long queue of packets is built up in the destination gateway and some packets are eventually lost. To release congestion and to achieve high throughput, we propose a rate-based congestion control scheme which is performed in the gateways. In the scheme, the destination gateway first calculates the available bandwidth from the queue length in its buffer, and then it assigns the bandwidth to the source gateways according to their transmission requirements. We introduce simple and explicit calculation methods for the available bandwidth of the destination gateway and for the bandwidth assignment to the source gateways.