Effect of load distribution in path protection of MPLS

摘要

We analyse and compare a protection mechanism based on load distribution with a typical protection mechanism in an multiprotocol label switching (MPLS) network. The protection mechanism based on load distribution is modelled as a fully shared mechanism (FSM) and the typical protection mechanism is, a partially shared mechanism (PSM). By comparing the FSM and the PSM, we numerically analyse the effect of load distribution in path protection of MPLS. The comparison is based on numerical equations representing the relationship between service reliability and resource utilization. From the equations, we show that both the FSM and the PSM have a tradeoff between service reliability and resource utilization. In addition, we provide solutions for the FSM and the PSM to determine the amount of bandwidth occupied according to the requested service reliability. The comparison of the FSM and the PSM shows that the PSM cannot provide greater service reliability than the FSM under the same utilization. In addition, the PSM is not capable of accommodating greater resource utilization than the FSM for the same level of service reliability. However, an appropriate choice of the number of protection paths allows the PSM to provide the same level of service reliability as the FSM. The choice is the maximum among the possible numbers of protection paths of the PSM. In short, the typical protection mechanism is as good as the FSM in terms of service reliability and resource utilization even though the FSM is an attractive alternative to the typical protection mechanism.