State-of-the-Art of the Architecture and Techniques for Delay-Tolerant Networks

The successful architecture and supporting protocols of today's Internet operate poorly when faced with operating environments characterized by very long delay paths and frequent network partitions.These problems are exacerbated by end-nodes that have severe power or memory constraints.Because of lacking "always-on" infrastructure in mobile and extreme environments,many such networks have their own specialized protocols,and do not utilize TCP/IP.To achieve interoperability between them,researchers had proposed a network architecture and application interface structured around optionally and reliable asynchronous message forwarding,with limited expectations of end-to-end connectivity and node resources.This architecture is called delay-tolerant networks(DTN).It operates as an overlay network above the transport layer.In this paper,we study the stateof-the-art architecture and key techniques for DTN,discuss their merits and deficiencies,and point out potential issues.It is our purpose to stimulate more research in this new promising network.