Towards Internet-wide Multipath Routing
Today's Internet would be more efficient and robust if routers could flexibly divide traffic over multiple paths. Often, having just a few alternate paths is sufficient for customizing paths for different applications, improving security, reacting to failures and balancing load. Yet alternate paths are often unavailable, due to two barriers. First, in a network the size of the Internet, moving to flexible multipath routing can impose significant computational and storage overhead on the routers. Second, the independent networks that comprise the Internet will not relinquish control over the flow of traffic without appropriate incentives. In this paper, we survey flexible multipath routing techniques which are both scalable and incentive compatible. Techniques covered include: multihoming, tagging, tunneling, and extensions to existing Internet routing protocols.