Persistent delivery with deferred binding to descriptively named destinations

Disruption-tolerant networks aim at reliable delivery of messages to their intended destinations even when continuous end-to-end paths are not available. Frequent network disruptions result in poor connectivity to name servers that can resolve destination names to specific network identifiers such as DNS names, IP addresses, or phone numbers. Disruptions also make it virtually impossible to keep dynamic distributed name databases residing on such name servers synchronized. Furthermore, in increasingly heterogeneous and multi-modal DTNs with a plethora of name spaces, a message source may not always be able to pre-determine the specific network address for a destination (as with DNS) or the mode of communication to reach it. In this paper, we describe a disruption-tolerant architecture and use cases for persistent message delivery to descriptively named destinations. We propose an intentional naming scheme that allows destinations to be described by their attributes (e.g., roles, services, or location) and predicates on them rather than by specific network identifiers. An intentional name denotes, in essence, a query on one or more namespaces which can result in specific endpoint identifiers (EID) of appropriate destination nodes. In our architecture, since it may not be possible to bind an intentional name to specific EID(s) at source, its resolution is deferred until the message is routed to one or more nodes that can successfully complete the process. We present a distributed progressive resolution procedure called GRAIN that persistently delivers messages to intentional names with geographic and role attributes, e.g., ldquoFirst responders within a kilometer of a specified locationrdquo. We describe results from a demonstration of GRAIN at a military facility.