Designing and characterizing overlay networks
Abstract
As widely adopted technologies tend to be ossified, Internet Service Providers (ISPs) are reluctant to adapt their core infrastructure to accommodate novel technologies. Overlay networks have emerged as a new strategy to suggest ways of introducing disruptive technology under these circumstances. Overlays can be used as a vehicle to implement new functionalities between the core IP networks and end-user computers, without the support from the ISPs. Several types of overlay networks for resilient routing, multicasting, quality of service, content distribution, storage, and object location have recently been proposed. Overlay networks offer several attractive features, including ease of deployment, flexibility and adaptivity, and an infrastructure for collaboration among hosts. Despite this potential, designing efficient, scalable, and secure overlay networks is a challenging problem. Since overlays utilize only unicasts among pairs of end-systems, they are prone to sacrifice performance compared with router-level solutions. We investigate a heuristic overlay multicast approach, which we refer to as Topology Aware Grouping (TAG). TAG exploits underlying network topology data to construct overlay multicast networks. This topology data is overlap in routes from the source among group members. We implement and experiment with TAG on the PlanetLab wide-area platform. Results demonstrate the effectiveness of our heuristic in reducing delays and duplicate packets. We also characterize the performance penalty for overlay multicast trees via experimental data, simulations, and theoretical models. Three overlay multicast protocols are compared with respect to various performance metrics. Overlay multicast routing strategies and host distribution, together with Internet topology characteristics, are identified as causes of the observed phenomena. Our results also quantify the overlay cost at the network-layer. In addition, we explore the potential of cooperation among co-existing, possibly heterogeneous, overlay networks. We investigate a spectrum of cooperative forwarding and information sharing services, and discuss the associated scalability, security, and heterogeneity problems. Motivated by these services, we design Synergy, an overlay internetworking architecture that fosters overlay cooperation. Our architecture promotes fair peer relationships among overlays to achieve synergism. Results indicate that Synergy can improve performance for overlay nodes, while maintaining the autonomy of individual overlay networks.
Degree
Ph.D.
Advisors
Fahmy, Purdue University.
Subject Area
Computer science
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