M.Sc Thesis

M.Sc StudentShochot Amnon
SubjectExtending BGP to Support the Concept of "Global AS"
DepartmentDepartment of Computer Science
Supervisor PROF. Reuven Cohen


The standard inter-domain routing protocol in the Internet today is Border Gateway

Protocol (BGP) version 4. Studies conducted in recent years reveal that BGP suffers from several inherent problems, the most important of which are slow convergence and instability. BGP is also known to suffer from lack of Quality of Service (QoS) and inter-AS multicast support. In this work we present a new paradigm, called the “Global ISP” (G-ISP) that aims in solving, or at least alleviating, the above-mentioned problems. One of the most important properties of the proposed paradigm is that it can be gradually deployed in the Internet.

A G-ISP can be viewed as an additional ISP that provides transit services to its customers over an Overlay Network. However, a customer of a G-ISP will usually have no direct connectivity with the G-ISP. Therefore, the BGP relationship between a G-ISP and its customers is conducted over a virtual link established over multiple intermediate physical links and routers. This is the main difference between a G-ISP and a “regular ISP” and it requires some extension to the standard BGP protocol.

This extension should be quite simple to implement and it complies

with the current BGP protocol. Moreover, the extensions affect only the BGP of

ASs that want to get the services of the G-ISP and therefore can be gradually deployed. We propose algorithms for building an efficient G-ISP overlay network, and test the feasibility of our solution. Finally we present possible applications of the G-ISP paradigm, and conclude this work.