A method for selecting a designation option of a class of data content, for delivery via a content delivery network, CDN, to content consumers (272 - 278), the CDN including: an entrance node through which the content enters the CDN; one or more intermediate nodes (254 - 262) through which the content traverses the CDN; and one or more edge nodes (264 - 270) for delivering the content to the content consumers, and the designation of the content determining how the content will be handled by the CDN as one of: a transport designation by which content is transported from the entrance node to one or more edge nodes; a caching designation by which the content is stored at one or more edge nodes; and a hybrid designation by which content is stored at a node in the CDN for subsequent transport to one or more edge nodes in the CDN, the method comprising: determining a set of one or more transport designation options each identifying a set of nodes and links between nodes for transporting the content from the entrance node to one or more edge nodes for delivery to content consumers; determining a set of one or more caching designation options each identifying a set of edge nodes for storage of the content; determining a set of one or more hybrid designation options each identifying a set of nodes for storage of the content and a set of nodes and links between nodes for transporting the stored content to edge nodes; determining a normalised measure resource requirement by normalising each of: a storage resource, a processing resource, and a network communication resource, for each of the transport, caching and hybrid designation options; and selecting one designation option for the class of content from all of the transport, caching and hybrid designation options by an optimisation function for selecting the designation option based on the determined normalised resource requirement for each option, said optimisation function includes either: determining all transport options between the entrance node and all edge nodes, determining all caching options for storage of the content at all edge nodes, and determining all hybrid options for storage of content and transport of content to all edge nodes; or determining an initial designation option for each of the transport, caching, and hybrid designation options, and determining one or more successive subsequent options based on adjustments to the initial designation options using any one of: a convergence approach, a contrastive divergence approach, a hill-climbing algorithm approach, and a search algorithm approach. determining a set of one or more transport designation options each identifying a set of nodes and links between nodes for transporting the content from the entrance node to one or more edge nodes for delivery to content consumers; determining a set of one or more caching designation options each identifying a set of edge nodes for storage of the content; determining a set of one or more hybrid designation options each identifying a set of nodes for storage of the content and a set of nodes and links between nodes for transporting the stored content to edge nodes; determining a normalised measure resource requirement by normalising each of: a storage resource, a processing resource, and a network communication resource, for each of the transport, caching and hybrid designation options; and selecting one designation option for the class of content from all of the transport, caching and hybrid designation options by an optimisation function for selecting the designation option based on the determined normalised resource requirement for each option, said optimisation function includes either: determining all transport options between the entrance node and all edge nodes, determining all caching options for storage of the content at all edge nodes, and determining all hybrid options for storage of content and transport of content to all edge nodes; or determining an initial designation option for each of the transport, caching, and hybrid designation options, and determining one or more successive subsequent options based on adjustments to the initial designation options using any one of: a convergence approach, a contrastive divergence approach, a hill-climbing algorithm approach, and a search algorithm approach. determining all transport options between the entrance node and all edge nodes, determining all caching options for storage of the content at all edge nodes, and determining all hybrid options for storage of content and transport of content to all edge nodes; or determining an initial designation option for each of the transport, caching, and hybrid designation options, and determining one or more successive subsequent options based on adjustments to the initial designation options using any one of: a convergence approach, a contrastive divergence approach, a hill-climbing algorithm approach, and a search algorithm approach.