Microsoft Technology Licensing, LLC

Pablo Rodriguez Rodriguez

Christos Gkantsidis

John L Miller

Stuart Ranson

Anders Edgar Klemets

Aamer Hydrie

Rebecca Claire Weiss

Manuel Costa

Bozidar Radunovic

Dinan Srilal Gunawardena

Peter Bernard Key

Armando Garcia-Mendoza

Wenjun Hu

A topology management process is implemented in peer-to-peer content distribution clouds using tracker nodes. Tracker nodes have information about available peers and assist peers in finding other peers to connect to. Various algorithms for use at the tracker nodes are described for selecting which peers to return as potentials for forming connections to. In addition, architectures and algorithms to allow efficient scaling of tracker nodes in peer-to-peer clouds are described.

Topology management in peer-to-peer content distribution clouds

The invention describes a control node for a content distribution network and a method of automatically verifying content distributed over a network at a node in the network. In the method, a content description is received which comprises a content identifier, a publisher identifier, publisher authorization information and content checking information. The integrity and validity of this information are checked and if both the checks are passed, the content description is stored.

Secure content descriptions

Managing content by influencing its distribution in the form of blocks or other units is crucial to the performance of a peer-to-peer content distribution system. We provide a content management module at each peer node to achieve this. The content management module implements a content request/response cycle in order to negotiate about blocks of content with other peer nodes. This cycle comprises an offer request, offer reply and a block request. These steps are preferably followed by data exchange and verification. The negotiation protocol used by our content management module provides a generic method that is advantageously used in conjunction with different encoding schemes such as full network coding and group network coding. In one embodiment we use group network coding and add information to the offer request and offer reply to facilitate efficient content distribution. Block request messages are selected to promote the use of on-the-fly decoding where possible.

Content management in peer-to-peer content distribution clouds

A method of transmitting data across a wireless mesh network is described which uses network coding at each of the intermediate nodes between the source node and the destination node. Each intermediate node also controls the rate at which it broadcasts packets based on link congestion and the backlog of packets at each of the possible next-hop nodes for the data flow.

Multipath forwarding algorithms using network coding

A wire protocol is described which implements connection management and other methods to give enhanced peer-to-peer content distribution. Connections between nodes can be placed in a 'notify' state when they are idle but may soon yield useful content. This notify state is also used together with a content request/response cycle to allow a peer to evaluate content available at a neighbour. If no suitable content is available a notify state is entered. When new content is later received at the neighbour it is able to inform the requesting node to allow it to restart the content request/response cycle.

Peer-to-peer message format data structure

A topology management process is implemented which involves removing or 'tearing down' connections between nodes in certain situations in order to try to replace those connections with more optimal ones. Idle connections are torn down unless those are in a 'notify' state; a notify state being one in which a request for content has been made to a neighbour but that neighbour has no available content as yet. Idle connections in a notify state are torn down only if they remain idle for a longer time than that required before an idle connection is torn down. To avoid problems caused by clusters of node forming and of loners being unable to join the cloud, network churn algorithms are taught. These involve requiring nodes to drop connections when specified conditions are met. Relative content distribution between connections is monitored and this information used to influence selection of those connections to drop.

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Barcelona, Spain

Pablo Rodriguez Rodriguez