Abstract: A content distribution mechanism that relies on cooperative desktop PCs to distribute content is disclosed. The mechanism distributes content in a robust manner by allowing at least one intermediate network node (i.e., between a source and client) to generate and send packets that contain a linear combination of the portions of content available at the node. Such linear combinations may be created by the source and client using at least a portion of the original content file in either encoded or unencoded form. After the client has received enough linearly independent combinations of packets, the original content may be reconstructed.

Abstract: Publishing content using a peer-to-peer content distribution system is described. A publisher is required to request authorization to publish from an authorization body. Resources such as tracker and seed nodes are allocated in a peer-to-peer content distribution system and pre-processing of content to be published is carried out. For example, a content description is generated for each item of content as well as a set of checksums or other items for validating blocks of content. Publication can be terminated in a variety of different ways. For example, by using expiry methods, by active revocation of publishers, authorization bodies, or individual items of content.

Abstract: 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.

Abstract: 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.

Abstract: 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 authorisation 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.

Abstract: The invention relates to content distribution over a network and provides methods of controlling the distribution, of receiving the content and of publishing content. The method of controlling distribution of content over a network includes receiving a content description and location information for a source of the content from a publisher, where the content description comprises authorisation details associated with the publisher.

Abstract: 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.

Abstract: 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.

Abstract: Publishing content using a peer-to-peer content distribution system is described. A publisher is required to request authorization to publish from an authorization body. Resources such as tracker and seed nodes are allocated in a peer-to-peer content distribution system and pre-processing of content to be published is carried out. For example, a content description is generated for each item of content as well as a set of checksums or other items for validating blocks of content. Publication can be terminated in a variety of different ways. For example, by using expiry methods, by active revocation of publishers, authorization bodies, or individual items of content.

Abstract: A method is described for anchoring IP flows in a network. An IP flow is transmitted by a mobile node and received at a access router attached to the mobile node. The IP flow is transferred to an original access router, which maintains a host table associated with the mobile node. And a server that is attached to the original access router may be accessed to service the IP flow.