A Graph Theoretic Perspective on Internet Topology Mapping

Understanding the topological characteristics of the Internet is an important research issue as the Internet grows with no central authority. Internet topology mapping studies help better understand the structure and dynamics of the Internet backbone. Knowing the underlying topology, researchers can better develop new protocols and services or fine-tune existing ones. Subnet-level Internet topology measurement studies involve three stages: topology collection, topology construction, and topology analysis. Each of these stages contains challenging tasks, especially when large-scale backbone topologies of millions of nodes are studied. In this dissertation, I first discuss issues in subnet-level Internet topology mapping and review state-of-the-art approaches to handle them. I propose a novel graph data indexing approach to to efficiently process large scale topology data. I then conduct an experimental study to understand how the responsiveness of routers has changed over the last decade and how it differs based on the probing mechanism. I then propose an efficient unresponsive resolution approach by incorporating our structural graph indexing technique. Finally, I introduce Cheleby, an integrated Internet topology mapping system. Cheleby first dynamically probes observed subnetworks using a team of PlanetLab nodes around the world to obtain comprehensive backbone topologies. Then, it utilizes efficient algorithms to resolve subnets, IP aliases, and unresponsive routers in the collected data sets to construct comprehensive subnet-level topologies. Sample topologies are provided at http://cheleby.cse.unr.edu

A Measurement Study on Overhead Distribution of Value-Added Internet Services ⋆

During the last two decades, several value-added services (e.g., IP multicast, IP traceback, etc.) have been proposed to extend the functional capabilities of the Internet. Due to the increasing role of these services, there is a need to better understand their impact on the network. In this paper, we present an experimental study on the intersection characteristics of end-to-end Internet paths and trees. We analyze these characteristics to understand the scale and the distribution of “state overhead ” that is incurred on the routers by various value-added network services. For the reliability of our analysis, a representative, end-to-end router-level Internet map is essential. Although several maps are available, they are at best insufficient for our analysis. Therefore, in the first part of our work, we exert a measurement study and present an alternative approach to obtain an end-to-end router-level map conforming to our constraints. In the second part, we conduct various experiments using our map and shed some light on the scale and distribution of the state overhead of value-added Internet services in both unicast and multicast environments