Modeling and performance analysis for IPv6 traffic with multiple QoS classes

This paper focuses on the modeling and performance analysis for IPv6 traf®c with multi-class QoS in virtual private networks (VPN). The multi-class QoS is implemented on differentiated service basis using priority scheme of 4 bits de®ned in the packet header of IPv6. A VPN-enabled IP router is modeled as a tandem queuing system in which each output link consists of two parallel priority output queues. The high-priority queue is used to carry the delay sensitive traf®c while the low-priority queue is used to carry the delay insensitive traf®c. On the other hand, multiple thresholds are implemented in each queue, respectively, for packet loss priority control. The performance analysis is done using ¯uid ¯ow techniques. The numerical results obtained from the analysis show that the differentiated service based on the priority schemes de®ned in IPv6 is able to effectively satisfy the multi-class QoS requirement for supporting multimedia services in VPN. The performance trade-off between the delay sensitive traf®c and delay insensitive traf®c in terms of traf®c throughput, packet loss probability and end-to-end delay in VPN networks is presented.