Cloud service routing in WDM networks with awareness on delay and link failure probability

Cloud service based on data center (DC) has become an attractive choice for abundant applications. Generally, DCs are distributed at different nodes across a given optical network, and users access DCs through predefined routes. From the perspective of service providers, it is important to offer reliable cloud service while taking service delay and service cost into consideration. In this paper, we study the service routing problem in a given optical network to provide cloud services with high reliability, where failure probability and transmission delay of each link are considered as two coupled parameters. The objective is to minimize the total routing cost and design the access routes for the demands originated from each node. To combine together the corresponding delay and the failure probability of each link, we introduce two cost scaling factors which can be flexibly adjusted to control their relative importance (i.e., the weights). Based on mathematical approximation, a novel method is proposed to compute the failure probabilities of individual service paths. This translates our objective function into a linear expression. Then, we formulate an integer linear program (ILP) to solve the problem. The proposed cloud service routing scheme is validated by extensive numerical experiments.