Abstract: A content request is sent (31) from a client (4) and the network routes (321) it to origin server (301) and mirrors (322) it to a transparent cache server (103). The transparent cache server (103) takes a decision on whether to deliver the content or not. If the transparent cache server (103) decides to deliver the content (33), it takes over the content delivery session setup between the client (4) and the origin server (301), impersonating and then disconnecting or triggering disconnection of the origin server (301). If the transparent cache server (103) is not delivering the content, due to cache failure, because the decision of the transparent cache server (103) is not to perform the delivery or because, being the decision of the transparent cache server (103) to deliver the content, the origin server (301) is still being connected, the content delivery session continues (34) between the origin server (301) and the client (4).

Abstract: A method of selecting a wavelength for use in transmitting optical data along a path in an optical network is disclosed. Previously known methods for selecting wavelengths do not consider how a wavelength selection decision will affect future connection attempts along paths that have one or more links in common with the path for which the wavelength is being selection. Consequently, a future connection attempt may be blocked because there are no wavelengths available end-to-end along the entire path that is to be set up.

Abstract: A method of establishing a path through an optical communications network is disclosed. Previously known method for establishing a path through an optical communications network include checking the viability of an end-to-end path once the complete end-to-end path has been selected. However, additional (and hence wasted) processing may be expended in selecting an end-to-end path that turns out not to be viable this increasing the network operating costs. In the proposed method one or more partial paths are evaluated according to a first criterion, candidate end-to-end paths are then evaluated according to a second criterion, wherein the end-to-end path evaluation disregards candidate end-to-end paths that include partial paths not meeting the first criterion.