Abstract: A partitioned network has several subdomains (1, 2, 3,) each having a respective access server (10, 20, 30) and each serving a plurality of end users (11, 12; 21, 22; 31, 32). Each access server (10, 20, 30) is connected to a respective content cache (13, 23) or a set of such caches (130, 131, 132), which stores content and downloads it to end users on request. An alternative routing (19, 29) may be available between an access server (10) and a content cache (23) other than its associated cache (13), for use in exceptional circumstances. All the content caches (13, 23), are given the same IP address, “W.X.Y.Z”. Each access server (10, 20, 30) operates exclusively in a geographic sub-domain, and recognizes the IP address W.X.Y.Z as relating uniquely to its respective associated content cache 13, (23, 23) This means that the configuration of each access server (10, 20, 30) to handle content caching/distribution/streaming can be the same regardless of its location in the network.

Abstract: A wavelength is selected for use in transmitting optical data along a path in an optical network. Wavelengths that are available for use end-to-end along the path are found, the wavelengths that are available on each link attached to each node on the path are found and a wavelength that is available end-to-end and that is more available on the links attached to the nodes is selected.

Abstract: A path is established through an optical communications network. One or more partial paths are evaluated according to a first criterion, and candidate end-to-end paths are then evaluated according to a second criterion. The end-to-end path evaluation disregards candidate end-to-end paths that include partial paths not meeting the first criterion. A path is established by selecting one of the candidate end-to-end paths on the basis of the second criterion.

Abstract: A content distribution platform (1) is arranged to distribute content by streaming over a communications network (4). The consumer (3) provides the content distributor (1) with marker data indicating where secondary content is to be inserted in a primary content stream. When the primary data is requested from a client platform (3), secondary content is inserted at the markers in the content stream. The secondary content to be inserted may be advertising material, data related to the primary data, or topical subjects, selected according to one or more characteristics associated with the client platform (3).

Abstract: Data may be delivered to an end user (40) from a data distribution server (30) hosting the data in any of two or more different modes. The delivery mode to be used is selected in accordance with user-specific network connection parameters retrieved by the data distribution server (30) from a store (20). The data in the store relates to parameters such as available bandwidth, and is maintained by interrogation or testing of the connections between the network (10) and end user (40).

Abstract: A partitioned network has several subdomains (1, 2, 3), each having a respective access server (10, 20, 30) and each serving a plurality of end users (11, 12; 21, 22; 31, 32). Each access server (10, 20, 30) is connected to a respective content cache (13, 23) or a set of such caches (130, 131, 132), which stores content and downloads it to end users on request. An alternative routing (19, 29) may be available between an access server (10) and a content cache (23) other than its associated cache (13), for use in exceptional circumstances. All the content caches (13, 23), are given the same IP address, “W.X.Y.Z”. Each access server (10, 20, 30) operates exclusively in a geographic sub-domain, and recognises the IP address W.X.Y.Z as relating uniquely to its respective associated content cache (13), (23, 23). This means that the configuration of each access server (10,20, 30) to handle content caching/distribution/streaming can be the same regardless of its location in the network.