Shared path protection under the risk of high-power jamming

Transparent optical networks are sensitive to high-power jamming which can degrade legitimate user signals via out-of-band effects in optical fibers and amplifiers, and in-band crosstalk in optical switches. Jamming signals can be inserted in the network either deliberately as an attack, with the intention to deteriorate service, or accidentally, due to component miscon-figuration. This type of attack/failure can potentially propagate through the network causing high data and revenue losses, requiring tailored survivability approaches which take these harmful effects into consideration. Namely, conventional network survivability approaches which protect transmission in case of component faults might not provide adequate protection from jamming since the working and backup paths of a connection may both be within reach of the same jamming signal, even if they are link/node disjoint. Previously, we proposed the concept of an Attack Group (AG) of an all-optical connection (referred to as a lightpath), comprised of all other lightpaths which potentially can affect it in case they carry a high-power jamming signal. Furthermore, we developed a jamming attack-aware dedicated path protection algorithm which establishes AG-disjoint working and backup paths for each connection. Herein, we extend this work by proposing an approach for Jamming-Aware Shared Path Protection (JA-SPP) to achieve survivability in the presence of jamming signals in a more resource-efficient way. We formulate the JA-SPP problem as an Integer Linear Problem (ILP) to obtain optimal solutions for smaller network instances. Comparison with standard SPP for single component faults (without jamming-awareness) shows that JA-SPP obtains solutions which offer protection from high-power jamming, in addition to single component faults, while using the same amount of resources (in terms of link and wavelength usage) as the standard SPP.

I. Introduction

In transparent optical networks (TONs), lightpaths are carried between source and destination entirely in the optical domain, without opto-electronic conversions at intermediate nodes. To efficiently utilize the optical fiber bandwidth, the available spectrum is divided into independent wavelengths, each supporting communication between a pair of end nodes, called Wavelength Division Multiplexing (WDM). Establishing a set of lightpaths over the existing physical topology implies solving the Routing and Wavelength Assignment (RWA) problem, i.e., finding a physical route and assigning a wavelength to each connection request. The RWA problem is NP-complete, so the Routing (R) and Wavelength Assignment (WA) phase are often solved subsequently. The WA subproblem, also NP-complete, is subject to wavelength clash and continuity constraints, which prohibit assigning the same wavelength to lightpaths which share a physical link and ensure each lightpath uses the same wavelength along its entire physical path, respectively.