QoS-Based and Network-Aware Web Service Composition across Cloud Datacenters
Dandan Wang, Yang Yang, Zhenqiang Mi · KSII Transactions on Internet and Information Systems · 2015
With the development of cloud computing, more and more Web services are deployed on geo-distributed datacenters and are offered to cloud users all over the world.Through service composition technologies, these independent fine-grain services can be integrated to value-added coarse-grain services.During the composition, a number of Web services may provide the same function but differ in performance.In addition, the distribution of cloud datacenters presents a geographically dispersive manner, which elevates the impact of the network on the QoS of composite services.So it is important to select an optimal composition path in terms of QoS when many functionally equivalent services are available.To achieve this objective, we first present a graph model that takes both QoS of Web services and QoS of network into consideration.Then, a novel approach aiming at selecting the optimal composition path that fulfills the user's end-to-end QoS requirements is provided.We evaluate our approach through simulation and compare our method with existing solutions.Results show that our approach significantly outperforms existing solutions in terms of optimality and scalability.