A Framework of Multipath Transport System Based on Application-Level Relay (MPTS-AR)

Multipath transport is an important way to improve the efficiency of data delivery. This document defines a multipath transport system framework in which application-level relays are deployed to provide the conditions to enable multiple paths between source and destination. In the proposed framework, endpoints are allowed to use multiple paths, including the default IP path and relay paths, to transport data in a single session. A relay path may via one or more application-level relays which provide application-level relay services for endpoints. This framework defines three kinds of logical entities including user agent, relay server and relay controller. Relay server provides relay service for user agents based on a local path-table. Relay controller manages relay servers and relay paths. User agent maintains multiple end-to-end paths which include a default path and multiple relay paths. The framework also defines a relay service control protocol named OpenPath protocol in control plane to manage relay servers and relay paths, and a profile of multipath transport protocol suite in data plane to facilitate multipath data transport. The multipath transport system framework can support various applications including applications requiring timely delivery of real-time data such as streaming media, and applications requiring ordered reliable delivery of stream of data such as file transfer.