H-Pastry: An inter-domain topology aware overlay for the support of name-resolution services in the future Internet

Overlay networks are widely used for locating and disseminating information by means of custom routing and forwarding on top of an underlying network. Distributed Hash Table (DHT) based overlays in particular, provide good scalability and load balancing properties. However, these come at the cost of inefficient routing, caused by the lack of adaptation to the underlying network, as DHTs often overlook physical network proximity, administrative boundaries and/or inter-domain routing policies. In this paper we show how to construct a DHT-based overlay network that takes all these aspects into account, so as to ease the global deployment of Future Internet architectures which require large-scale name resolution, such as Information-Centric Networking (ICN) and the Internet of Things (IoT). Based on the Pastry distributed object location and routing substrate and the Canon paradigm for multi-level DHTs, we developed H-Pastry, an overlay DHT scheme that harvests the scalability and load balancing features of DHTs, while also adapting to the underlying network topology, administrative structure and routing policies. We evaluate the performance characteristics of the proposed scheme through an extensive set of detailed simulations over realistic inter-network topologies. Our results show that H-Pastry substantially improves routing by reducing both overlay path stretch (by up to 55%) and routing policy violations (by up to 70%), compared to the Canonical (multi-level) Chord DHT. In addition, the design of H-Pastry keeps traffic within administrative boundaries as far as possible, reducing inter-domain hops by up to 27% compared to Pastry, while also creating excellent opportunities for the support of caching and multicast.