The Taub Faculty of Computer Science Events and Talks

Network Function Virtualization (NFV) is a novel paradigm that enables flexible and scalable implementation of network services on cloud infrastructure, while Network Survivability is an traditional well-studied subject for maintaining network service continuity in the presence of failures. This talk will address these two important subjects through the results of two recent papers, namely "Optimal Link-Disjoint Node-“Somewhat Disjoint” Paths"[1] and "The Actual Cost of Software Switching for NFV Chaining"[2].

In [1], we investigate a crucial research problem in this context is the identification of suitable pairs of disjoint paths. Here, “disjointness” can be considered in terms of either nodes or links. Accordingly, several studies have focused on finding pairs of either link or node disjoint paths with a minimum sum of link weights. In this study, we investigate the gap between the optimal node-disjoint and link disjoint solutions. Specifically, we formalize several optimization problems that aim at finding minimum-weight link-disjoint paths while restricting the number of its common nodes. We establish that some of these variants are computationally intractable, while for other variants we establish polynomial-time algorithmic solutions. Finally, through extensive simulations, we show that, by allowing link-disjoint paths share a few common nodes, a major improvement is obtained in terms of the quality (i.e., total weight) of the solution.

In [2], we conduct an extensive and in-depth evaluation that examines the impact of service chaining deployments on Open vSwitch – the de facto standard software switch for cloud environments. We provide insights on network performance metrics such as latency, throughput, CPU utilization and packet processing, while considering different placement strategies of a service chain. We then use these insights to provide an abstract generalized cost function that accurately captures the CPU switching cost of deployed service chains. This cost is an essential building block for any practical optimized placement management and orchestration strategy for NFV service chaining.

[1] Jose Yallouz, Ori Rottenstreich, Péter Babarczi, and Ariel Orda, "Optimal Link-Disjoint Node-'Somehow Disjoint' Paths", IEEE ICNP '16, Singapore, November 2016.
[2] Marcelo Caggiani Luizelli, Danny Raz, Yaniv Saar and Jose Yallouz, "The Actual Cost of Software Switching for NFV Chaining", accepted to IEEE IM '17.

Bio:
Jose Yallouz received a Ph.D. and a B.Sc. from the Electrical Engineering department of the Technion at 2016 and 2008, respectively. He recently joined the Core Architecture team at Intel Corporation. He was a recipient of the Israel Ministry of Science Fellowship in Cyber and advance Computing award. Among his past activities were the organization of the CeClub seminar and the Netmeeting forum. He is mainly interested in computer networks, computer architecture and compilers.