Ph.D Thesis

Ph.D StudentNakibly Gavriel
SubjectTraffic Engineering in IP and MPLS Networks
DepartmentDepartment of Computer Science
Supervisor PROF. Reuven Cohen
Full Thesis textFull thesis text - English Version


Traffic engineering is a set of actions whose goal is to evaluate and optimize the performance of operational networks. One of the most important traffic engineering actions is the control of the routing function in the network so that traffic can be steered through it as effectively as possible.

This thesis contains three parts. The first two parts address traffic engineering in IP networks and the third addresses traffic engineering in MPLS networks. In the first part we study the computational complexity and effectiveness of a concept we term “N-hub Shortest-Path Routing” in IP networks. N-hub Shortest-Path Routing allows the ingress node of a routing domain to determine up to N intermediate nodes (“hubs”) through which a packet will pass before reaching its final destination. This facilitates better utilization of the network resources, while allowing the network routers to continue to employ the simple and well-known shortest-path routing paradigm. Our results show that N-hub Shortest-Path Routing can increase network utilization significantly even for N=1. Hence, this routing paradigm should be considered as a powerful mechanism for future routing in the Internet.

In the second part, we consider the application of “N-hub Shortest-Path Routing” to network services traffic. Network services are provided by means of dedicated service gateways, through which traffic flows are directed. We propose a novel approach for the service placement problem, which takes into account traffic engineering considerations. Rather than trying to minimize the length of the traffic flow detours, we take advantage of them in order to enhance the overall network performance. Our main contribution is showing that placement and selection of network services can be used as effective tools for traffic engineering.

In the third part, we consider the MPLS recovery mechanisms. These mechanisms are increasing in popularity because they can guarantee fast restoration and high QoS assurance. Their main advantage is that their backup paths are established in advance, before a failure event takes place. In this thesis we present a comprehensive study on restorable throughput maximization in MPLS networks. One of our most important conclusions is that when one seeks to maximize revenue, local recovery should be the recovery scheme of choice.