Extending Bgp to Support the Concept of “global As”

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, its effect on the BGP protocol, algorithms for building a G-ISP overlay network, and possible applications of the G-ISP paradigm are described in this thesis. T ec hn io n C om pu te r Sc ie nc e D ep ar tm en t M .S c. T he si s M SC -2 00 502 2 00 5