Underlay-aware overlay networks

• Authors: Philip K. Mckinley;Chiping Tang
• Venue: Underlay-aware overlay networks
• Year: 2005

An overlay network is a logical abstraction of the underlying physical network, comprising end nodes and paths between end-node pairs. Many applications, such as multicast and content distribution, can exploit the high flexibility, deployability, and computing capability of end systems to provide better network services. Overlay networks provide a software infrastructure on which to build such applications. A fundamental issue in overlay network management is the construction of the overlay topology. The performance and reliability of an overlay topology depends on the structure of the underlying physical topology, the characteristics of the end nodes, and the qualities of the end-to-end paths connecting those nodes. We define the set of comprised physical links of the end-to-end paths as the underlay of the overlay network. In this research, we investigate the potential costs and benefits of exploiting underlay information to facilitate overlay network construction and adaptation. Our contributions can be summarized in the following two areas. First, we propose several algorithms that exploit underlay information to conduct efficient path monitoring and construct high-quality overlay topologies. (1) We exploit the overlap among overlay paths in sparse networks to design an underlay-aware monitoring approach that trades probing overhead for estimation accuracy in such environments. The approach uses network-level path composition information to infer path quality without full-scale pairwise probing. It can significantly reduce probing overhead while providing bounded quality estimations for all n × ( n - 1) overlay paths. (2) We introduce an underlay-aware spanning tree construction algorithm for endsystem multicast. The algorithm uses network-level path composition information to build an overlay spanning tree that minimizes maximum link-stress while satisfying diameter constraints. (3) We study the problem of multipath overlay routing. We propose an underlay-aware algorithm that uses network-level path composition and quality information to select multiple paths between source and destination nodes. The algorithm can be used to improve communication quality in systems where data traffic on different paths interacts with each other. Second, we address the implementation issues associated with the proposed algorithms. (1) We propose a distributed implementation of the underlay-aware monitoring approach. The implementation uses a minimum diameter, link-stress bounded overlay spanning tree constructed by the underlay-aware spanning tree algorithm to disseminate path quality information. This implementation can reduce probing overhead while balancing link stress on the spanning tree. (2) We investigate practical issues of implementing the underlay-aware monitoring approach in peer-to-peer networks where participating nodes may be selfish. We propose pricing mechanisms to charge nodes that request monitoring results, with payments to the nodes that conduct monitoring. These mechanisms can encourage truthful collaboration among peer nodes and help to achieve optimality of the proposed underlay-aware monitoring approach. (3) We design a distributed multipath chassis for overlay network applications that use the underlay-aware multipath algorithm. The chassis combines the dissemination of path quality and composition information with parallel path exploration to facilitate joint path quality computation and path selection. In summary, this research reveals that overlay network applications can exploit network underlay information to conduct efficient path monitoring and construct high-quality overlay topologies such as spanning trees and multipath plans. The proposed approaches can be used in practical overlay systems to improve communication efficiency and adaptability.