A Study on the Design of Survivable Optical Virtual Private Networks (O-VPN)

This paper tackles the resource allocation problem in wavelength division multiplexing (WDM) networks supporting virtual private networks (O-VPN), in which working, and spare capacity are allocated in the networks for satisfying a series of traffic matrices corresponding to a group of O-VPN. Based on the (M:N)ⁿ protection architecture where multiple protection groups (PG) are supported in a single network domain, we propose two novel integer linear programming (ILP) models, namely ILP-I, and ILP-II, aiming to initiate a graceful compromise between the capacity efficiency, and computation complexity without losing the ability of addressing the quality of service (QoS) requirements in each O-VPN. ILP-I considers all the connection requests of each O-VPN in a single formulation, which may suffer from long computation time when the number of connection requests in an O-VPN is large. To trade capacity efficiency with computation complexity, ILP-II is developed such that each O-VPN can be further divided into multiple small PG based on specific grouping policies that satisfy multiple QoS requirements. With ILP-II, it is expected that all the working, and spare capacity of the O-VPN can be allocated with a polynomial time complexity provided that the size of each PG is well constrained. Experimental results show that, in terms of capacity efficiency, a significant improvement can be achieved by ILP-I compared to that by ILP-II at the expense of much more computation time. Although ILP-II is outperformed by ILP-I, it can handle the situation with an arbitrary size of O-VPN. We conclude that the proposed ILP-II model yields a scalable solution for the capacity planning in the survivable optical networks supporting O-VPN based on the (M:N)n protection architecture