Traffic Characteristics in OBS Networks

Abstract

Modeling and analysis of the OBS networks is a challenging task due to the unacknowledged switching used and the lack of optical buffers at the core nodes. Further, due to the aggregation of packets into bursts at the ingress nodes, the characteristics of the IP traffic are changed inside the OBS network. It is essential to analyze the characteristics of the traffic in the OBS networks to understand their performance. The characteristics of the traffic are mainly influenced by the burst assembly and disassembly as well as the burst loss in the core network. There are also a larger number of functional components in an ingress node compared to the egress node. Apart from this the ingress nodes are also responsible for the generation of BHPs and the determination of the offset time. Therefore, to study the characteristics of the traffic in the OBS networks, it is enough to analyze the components of an ingress node that are responsible for the formation and the transmission of the bursts. The function of the egress node is only to disassemble the bursts into the corresponding IP packets and forward them through the access network. Further, the traffic out of the egress node is not a part of the OBS network so that the influence of the egress node on the traffic characteristics can be neglected. The analysis of the traffic characteristics in the OBS networks helps to understand the performance of the network in terms of blocking probability, throughput, and delay.