Link Bandwidth Design Method Considering Failures in IP Network

This paper proposes a link bandwidth design method considering failures in an IP network. When we design the link bandwidth, we need to consider rerouted traffic's bandwidth by failures in order to avoid the traffic congestion. If we knew the point-to-point traffic matrix, we could easily obtain the required link bandwidth after failures. However, the support in routers for measuring traffic matrices is poor and it is generally difficult to measure traffic matrices in a large network. The proposed method does not need traffic matrix measurement; instead, it uses link load measurement before failures which is generally easy to measure. Then, the proposed method calculates the logical least upper bound (in mathematical other words, supremum or sup) of the bandwidth variation at each link by failures by using Linear Programming (LP). Simulation results show that the link bandwidth amount designed by the proposed method is close to the real required amount, which needs traffic matrix measurement. That is, the proposed method provides little wasted bandwidth using link load measurement only. Compared with the simple method which also uses only link load measurement, the proposed method achieves 50% reduction in wasted bandwidth.