Application-Layer Traffic Optimization (ALTO)

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A significant part of the Internet traffic is today generated by peer-to-peer applications used for file sharing, real-time communications and live media streaming. Contrary to client/server architectures, P2P applications access resources (e.g. files or media relays) distributed across the Internet and exchange large amounts of data in connections that they establish directly with nodes hosting such resources. In this context, addressing the Application-Layer Traffic Optimization (ALTO) problem means, on the one hand, providing topology information regarding the underlying network to P2P applications and, on the other hand, enhancing P2P applications in order to use such information to select the best endpoints among those that are available for the connections they are going to establish.

The ALTO problem has been addressed in many venues and several solutions have already been proposed (an incomplete list is available in the Resources section); the goal of this specific effort is, starting from an analysis of such solutions, to define a protocol which could be used by Internet Service Providers and P2P applications for exchanging topology information in order to optimize the network traffic they generate.

A complete statement of the ALTO problem is availabe as an Internet-Draft.

The version of the charter currently discussed on the mailing list is available at http://alto.tilab.com/docs/charter.txt.