Assembly admission control based on random packet selection at border nodes in Optical Burst-Switched networks

Abstract

In Optical Burst-Switched (OBS) networks employing Just Enough Time (JET) signalling, Burst-Control Packets request resources at intermediate nodes following a one-way reservation protocol, that is, requested resources are not confirmed back to the source. Hence, data bursts are transmitted without any guarantees, and it sometimes occurs that these are dropped at a certain hop in the source-destination path, hence wasting resources at previous hops. This effect is specially harmful if some connections are abusing of the global shared resources, violating their respective Service Level Agreements, thus causing: (1) global performance degradation; and, (2) unfair service received by other connections. This article proposes "Random Packet Assembly Admission Control", an admission control mechanism for OBS networks that moderates the two problems above. The mechanism monitors the network load status, detects which links are heavily loaded and decides which flows among the total traversing them require throughput decrease, on attempts to alleviate congestion and benefit other flows which are not abusing from the network. Such throughput decrease consists of preventive packet dropping during the assembly process at the ingress nodes of the OBS network, thus making no use of the network core. The numerical results show a substantial increase in the throughput experienced by wellbehaved flows, and fundamental fairness achievement in the use of optical resources.