QoS-aware flow control in next generation packet networks

Abstract

Needs for various delay-sensitive applications, such as Voice-over -IP (VoIP), Internet Protocol Television (IPTV), and interactive gaming, which requires tightly low end-to-end delay and delay jitter, and low packet loss rate have been increasing. In order to support this trend, it is essential to develop an efficient and QoS-aware networking technology. Optical Packet Switching (OPS) including Optical Burst Switching (OBS) is a networking technology enabling to switch and transport optical packet-level data traffic beyond simple point-to-point transmission. Especially, through OPS technology, we can achieve high multiplexing efficiency owing to packet-level switching as well as provide delay-guaranteed service owing to cut-through switching mechanism at core nodes. However, OPS technology has several limitations to support QoS-guaranteed services. First, it``s not doable to provide absolute QoS even for high priority traffic such as delay-sensitive application traffic. Second, blocking rate among data bursts at core nodes is not quite acceptable to satisfy service requirements. Third, installation cost (i.e.,CAPEX) and operating cost (i.e., OPEX) could be increased by supplementary equipment such as Fiber Delay Line (FDL) buffer used for relaxing contention of data bursts. Lastly, network utilization of OPS is degraded as increasing traffic load because of high contention among data bursts. In order to build QoS-guaranteed and cost-effective next generation packet network based on OPS, it is essential to provide revolutionary solutions for aforementioned problems of OPS. As a common solution for the problems of OPS, we considered flow control mechanism in OPS, naming OPS flow control. General concept of flow control is the process of managing the rate of data transmission between two nodes to prevent a fast sender from over running a slow receiver. A well-known mech-mechanism to know this congestion is to request acknowledged packet from destination node. H...