The Taub Faculty of Computer Science Events and Talks

Coping with network failures has been recognized as an issue of major importance in terms of security, stability and prosperity. It has become clear that current networking standards fall short of coping with the complex challenge of surviving failures. The need to address this challenge has become a focal point of networking research. Accordingly, the goal of this research is to establish a comprehensive methodology for efficiently providing network survivability in conjunction with other major QoS requirements. This novel methodology should reflect a multi-perspective consideration, including theoretical aspects as well as the development of new QoS metrics.

In this talk, we will mainly focus on the concept of tunable survivability, which offers major performance improvements over traditional approaches. Indeed, while the traditional approach is to provide full (100%) protection against network failures through disjoint paths, it was realized that this requirement is too restrictive in practice. Tunable survivability provides a quantitative measure for specifying the desired level (0%-100%) of survivability and offers flexibility in the choice of the routing paths in unicast and broadcast transmission methods. For unicast, we establish efficient algorithmic schemes for optimizing the level of survivability under additive end-to-end QoS bounds. Moreover, we establish some (in part, counter-intuitive) properties of the optimal solution. For broadcast, we investigate the application of tunable survivability for the maintenance of spanning trees under the presence of failures and establish efficient algorithmic schemes for optimizing the level of survivability under various QoS requirements. In addition, we derive theoretical bounds on the number of required trees for maximum survivability. Finally, through extensive simulations, we demonstrate the effectiveness of the tunable survivability concept for both methods.

If time permits, we will also cover the following topics studied during this thesis:

- A study which investigates the gap between the optimal disjoint-node path pair and the disjoint-link path pair by relaxing the classical "full disjointness" requirement.
- Design aspects of Stackable Routers, i.e. a class of independent routing units operating together as a single router, and the analysis of schemes for improving their performance.
- A study focusing on the number of shortest paths that can be covered by a single spanning tree.

Bio:
Jose Yallouz is a Ph.D. candidate in the Electrical Engineering department of the Technion, Haifa, Israel. He received the B.Sc. from the same department in 2008. He is a recipient of the Israel Ministry of Science Fellowship in Cyber and advance Computing award. Among his activities are the organization of the CeClub seminar and the Netmeeting forum. He is mainly interested in computer networks, algorithm design, survivability, QoS, SDN and NFV architectures.