Survivable MPLS Over Optical Transport Networks: Cost and Resource Usage Analysis

Abstract

Abstract-In this paper we study different options for the survivability implementation in MPLS over Optical Transport Networks (OTN) in terms of network resource usage and configuration cost. We investigate two approaches to the survivability deployment: single layer and multilayer survivability and present various methods for spare capacity allocation (SCA) to reroute disrupted traffic.The comparative analysis shows the influence of the offered traffic granularity and the physical network structure on the survivability cost: for high bandwidth LSPs, close to the optical channel capacity, the multilayer survivability outperforms the single layer one, whereas for low bandwidth LSPs the single layer survivability is more cost-efficient. On the other hand, sparse networks of low connectivity parameter use more wavelengths for optical path routing and increase the configuration cost, as compared with dense networks. We demonstrate that by mapping efficiently the spare capacity of the MPLS layer onto the resources of the optical layer one can achieve up to 22% savings in the total configuration cost and up to 37% in the optical layer cost. Further savings (up to 9 %) in the wavelength use can be obtained with the integrated approach to network configuration over the sequential one, however, at the increase in the optimization problem complexity. These results are based on a cost model with different cost variations, and were obtained for networks targeted to a nationwide coverage. Index Terms-MPLS over OTN, multilayer network design, multilayer routing, spare capacity allocation, survivability design.

A Novel Class-Based Protection Algorithm Providing Fast Service Recovery in IP/WDM Networks

“…Zhao et al [16] proposed a similar strategy for IP/GMPLS/OTN networks. Bigos et al [2], and Liu, Tipper and Vajanapoom [6] described various methods for spare capacity allocation (SCA) to reroute disrupted traffic in MPLS-over-OTN. Doucette, Grover and Giese [4] used the spare capacity of span-protecting p-cycles to provide protection against both optical link and node failures in the IP-MPLS layer.…”

Optimizing Node Capacity in Multilayer Networks

“…Previous works on multilayer networks [2], [3] have primarily concentrated on the two-layer architecture such as IP-over-WDM [4], [5]. Even those who considered the OTN layer, such as [6], [7], have not explicitly addressed the distinct technological constraints of OTN. That is, the core routers are connected through electro-optical cross-connects (OXCs) with no absorption for OTN as a distinguished layer with unique stipulations.…”

Two-layer mesh network optimization based on inter-layer decomposition

“…Thus, the lowspeed connection requests are efficiently groomed and routed in the two-layer mesh network. Traffic grooming in two-layer mesh networks comprises plenty of problems, including network planning and virtual topology design (based on static traffic demand) [6,7], dynamic lightpath establishment (based on dynamic traffic demand) [8], and their extension problems, such as survivable traffic grooming [9][10][11], multicast and anycast traffic grooming [12,13], etc. The traffic-grooming problem in twolayer mesh networks based on static traffic demands is essentially an optimization problem, which can be theoretically solved by integer linear programming (ILP).…”

“…The authors also analyze the results of their ILP formulations, which can generate optimal solutions for small-scale networks. The authors of [10] focus on two optimization models for a two-layer design: overlay model and integrated model, and present an ILP formulation for the problem of minimizing network cost based on these two models. The ILP results show that the overlay model can solve the working paths for a 15-node network, but cannot solve the corresponding protection paths, since an integrated model consumes more calculation time than an overlay model and does not obtain the solution for the working paths and protection paths for the 15-node network.…”

“…From the above discussion on the traffic-grooming problem for static traffic demand [6,7,9,10], we can observe that mathematic optimization (as ILP) is the primary method. However, in practice, the integrated two-layer ILP formulation considering a traffic-grooming problem in two-layer mesh networks is always adapted for small-scale mesh networks.…”