Performance Analysis and Improvement of Topology Discovery Protocols in Home Networks

Abstract

The growing popularity of the Internet and the increasing demand of services based on IP have influenced the evolution of home networks. From a simple network constituted by just a PC and a modem, the home network has become a complex environment providing connectivity to several devices with different capabilities. Although service providers possess tools to manage their own core and access networks, they lack the tools to get information related to home network characteristics. Due to the impact of home network configurations on delivered services, operators are interested in diagnostic tools able to gather information about the topology of the home network, the link layer technologies that are used and which are the active devices requiring home network connectivity. The goal of this thesis is to study the currently available topology discovery protocols and evaluate their suitability for home networks. Our work focuses on two protocols that are believed by the service providers’ community to be appropriate for the home network scenario. These two protocols are the Link Layer Topology Discovery (LLTD) protocol and the Link Layer Discovery Protocol (LLDP), the latter also known as IEEE 802.1AB. Our study includes the definition of a set of performance indicators for topology discovery protocols and a performance analysis of LLTD and LLDP for different conditions and topologies. We designed several experiments representing the most common home network configurations, and carried out measurements that provide the data needed for our analysis. Based on the obtained results, we then proposed a novel topology discovery architecture, called Home Network Topology Discovery (HNTD) that fulfills most of operators’ requirements, in contrast to LLTD and LLDP.