This Special Issue presents extended versions of selected papers from 3rd International Workshop on Reliable Networks Design and Modeling (RNDM 2011) held in Budapest, Hungary on October 3–5, 2011. This event, organized by Gdansk University of Technology (PL) in co-operation with Concordia University (CA), and atesio GmbH (DE), was technically co-sponsored by IFIP TC6 WG 6.10 and IEEE.

Similar to previous editions, RNDM 2011 provided a very successful discussion forum for people from academia and industry. After a detailed review process, 27 accepted papers written by authors from 23 countries, were organized into seven technical sessions, namely: “Optical Networks Survivability”, “Resilience of Multilayer and Overlay Networks”, “Models and Algorithms of Survivable Networks Design”, “Network Reliability Assessment”, “Theory of Network Reliability”, “Survivability of Anycast and Multicast Networks”, and ”Shared Link Risk Groups”.

Authors of 15 papers of high merit were next invited to submit the extended versions to this Special Issue. Final acceptance of papers included here was conditional upon receiving appropriate positive review scores, and carefully addressing the reviewers’ remarks. Each of the papers is briefly introduced below.

The paper Resilient Network Design: Challenges and Future Directions, by David Tipper provides an overview of current trends and directions in reliable networks design. In particular, it discusses the complexity and challenges of providing reliable services in evolving communications infrastructure. James P.G. Sterbenz et al. discuss in their paper entitled Redundancy, Diversity, and Connectivity to Achieve Multilevel Network Resilience, Survivability, and Disruption Tolerance three critical resilience disciplines and the corresponding mechanisms to achieve multilevel resilience, namely: redundancy for fault tolerance, diversity for survivability, and connectivity for disruption tolerance. The paper entitled Highly Available Network Design and Resource Management of SINET4 by Shigeo Urushidani et al. presents a very interesting analysis of a Japanese academic backbone network reliability following from real information achieved during the disastrous March 11 Great East Japan Earthquake.

In Path Diversification for Future Internet End-to-End Resilience and Survivability, Justin Rohrer et al. describe a new method called “path diversification” providing multiple paths to increase the reliability of flows. A Hybrid Rerouting Scheme by Akli Fundo et al. includes another important proposal of a method aimed to provide cost-efficient reliable routing by means of combining the following three restoration techniques, namely path diversity, end-to-end rerouting with stub release, and global rerouting. Investigations on all-terminal reliability are presented in a paper Inflection Points for Network Reliability by Jason Brown et al. In particular, the authors show that the all-terminal reliability of almost every simple graph has a point of inflection. Another important result is that there are infinite families of graphs with more than one point of inflection.

The next two papers refer to the concept of loop-free alternate path (LFA). In particular, Wouter Tavernier et al. in Self-configuring Loop-Free Alternates with High Link Failure Coverage present a logical extension of the loop-free alternate concept, introducing a self-configuring scheme to populate the corresponding alternate entries, and provide the respective evaluation of the method performance in terms of obtained coverage, configuration time, and path length. In Optimization Methods for Improving IP-level Fast Protection for Local Shared Risk Groups with Loop-Free Alternates, Máté Nagy et al. include a novel bipartite graph model for the LFA graph problem extended to the case of multiple failures using the concept of Shared Risk Groups, and present a set of heuristic algorithms to obtain the approximate solutions.

The next paper by Michał Kucharzak and Krzysztof Walkowiak entitled Modeling and Optimization of Maximum Flow Survivable Overlay Multicast with Predefined Routing Trees refers to multicast traffic protection in overlay networks aimed at realizing maximum throughput with survivability constraints.

Providing protection of flows by means of protection cycles (p-cycles) is another recent topic addressed in papers A Heuristic Approach to Working and Spare Capacity Optimization for Survivable Anycast Streaming Protected by p-Cycles by Adam Smutnicki and Krzysztof Walkowiak, and Robust FIPP p-Cycles against Dual Link Failures by Brigitte Jaumard et al. The former one provides solutions for anycast traffic protection, while the latter paper presents the application of Failure-Independent Path-Protecting (FIPP) p-cycles to achieve protection against simultaneous failure of two links.

Next three papers address the issue of optical networks reliability. The first of them entitled Survey on Out-of-Band Failure Localization in All-Optical Mesh Networks by Janos Tapolcai presents an overview of recent research trends with respect to out-of-band monitoring. The paper Methods for Physical Impairment Constrained Routing with Selected Protection in All-Optical Networks by Peter Soproni et al. analyzes the problem of survivable all-optical routing in WDM networks with physical impairments. In particular, the authors introduce methods to maximize the number of demands routed with protection in all-optical way in capacity-constrained networks with limitations on path lengths according to physical impairments. Ali Shaikh and Brigitte Jaumard introduce in Optimized Dimensioning of Resilient Optical Grids with Respect to Grade of Services a scalable optimization model for maximizing IT services in optical grids subject to survivability mechanisms.

The last paper by Mateusz Żotkiewicz and Michał Pióro entitled Exact Approach to Reliability of Wireless Mesh Networks with Directional Antennas refers to reliability of wireless mesh networks—being currently an emerging area of research. In particular, the authors discuss an optimal way of solving the cost minimization problem. An extensive numerical study is presented to illustrate the efficiency of the proposed method.

The editors of this Special Issue would like to express their gratitude to the Editor of TSJ for his consent to publish RNDM 2011 materials in the Journal, as well as to reviewers for delivering the detailed reviews.