A Fairness Analysis of LAN/WAN Protocol Relays

Functional standardization activities in ISO and in regional workshops are currently addressing network layer relays for the interconnection of several types of subnetworks. Relay systems are critical systems in the overall performance of the network because they are the points where network congestion can be build up or avoided. Particularly, when the interconnected subnetworks have very dissimilar bandwidths, congestion control becomes a very important issue in relay systems design. This paper addresses the problem of congestion control in relay systems for LAN/WAN interworking. Congestion control deals with the avoidance of collapse situations in intermediate systems due to traffic overload. It deals also with the guarantee of fairness in resource utilization, considering user needs of communication services expressed in terms of Quality of Service (QoS) parameters. To ensure congestion collapse avoidance and fairness, a channel service algorithm is proposed. Simulation results show that, in a situation of overload and for different traffic patterns with different QoS requirements, the relay’s channel service and acknowledgment algorithms can guarantee justice in resource utilization and the expected QoS among the active channels.