Abstract: Methods and apparatus are disclosed for configuring one or more processors to implement service function chains comprising one or more virtualised service functions. A method according to one aspect, performed by a processing module (330) implemented on one or more processors (30), involves steps being performed in respect of at least one new virtualised service function (33) to be included in a service function chain of: determining a position in the service function chain at which the new virtualised service function (33) is to be included; allocating at least one internal address to the new virtualised service function, the at least one internal address being an address to be usable by a switching processor (34); and providing to the switching processor (34) an indication of the at least one internal address allocated to the new virtualised service function (33).

Abstract: A connection (5) to a first network (3, 13) is connected by way of a first routing processor (4) to a switching processor (14), which has a connection (35) to a network address translation processor (17) providing access to one or more hosted functions (22). Connections (6, 25) separate from the network address translation processor (17) are made to one or more hosted functions (9, 16, 23), incompatible with the NAT process, and also to a second network (2). This allows connections not requiring NAT to avoid the delays incurred by that process. Data packets are routed to the network address translation processor (17) or the first routing processor (4) in accordance with header information in the packet identifying a transmission control processor (17) and the second interface (35).

Abstract: Methods and apparatus are disclosed for transmitting flows of data units across a data communication network from a transmitting node towards an intended destination via one or more intermediate nodes, the data units having destination indications, the intermediate nodes being configured to receive data units, identify therefrom a transmission mode that has been selected from at least two transmission modes for the data units, and forward the data units according to the selected transmission mode. The method involves selecting a transmission mode for the flow in dependence on an estimate of the difference in the amount of a resource required to transmit the flow by one or the other transmission mode, a resource-usage measure indicative of the amount of the resource required to identify a route and reserve sufficient capacity thereon for transmission of the flow, and a probability measure indicative of a likelihood of success of an attempt to identify and reserve sufficient capacity for the flow.

Abstract: Methods and apparatus are disclosed for configuring one or more processors to implement service function chains comprising one or more virtualised service functions. A method according to one aspect, performed by a processing module (330) implemented on one or more processors (30), involves steps being performed in respect of at least one new virtualised service function (33) to be included in a service function chain of: determining a position in the service function chain at which the new virtualised service function (33) is to be included; allocating at least one internal address to the new virtualised service function, the at least one internal address being an address to be usable by a switching processor (34); and providing to the switching processor (34) an indication of the at least one internal address allocated to the new virtualised service function (33).

Abstract: A connection (5) to a first network (3, 13) is connected by way of a first routing processor (4) to a switching processor (14), which has a connection (35) to a network address translation processor (17) providing access to one or more hosted functions (22). Connections (6, 25) separate from the network address translation processor (17) are made to one or more hosted functions (9, 16, 23), incompatible with the NAT process, and also to a second network (2). This allows connections not requiring NAT to avoid the delays incurred by that process. Data packets are routed to the network address translation processor (17) or the first routing processor (4) in accordance with header information in the packet identifying a transmission control processor (17) and the second interface (35).

Abstract: Methods and apparatus are disclosed for transmitting flows of data units across a data communication network from a transmitting node towards an intended destination via one or more intermediate nodes, the data units having destination indications, the intermediate nodes being configured to receive data units, identify therefrom a transmission mode that has been selected from at least two transmission modes for the data units, and forward the data units according to the selected transmission mode. The method involves selecting a transmission mode for the flow in dependence on an estimate of the difference in the amount of a resource required to transmit the flow by one or the other transmission mode, a resource-usage measure indicative of the amount of the resource required to identify a route and reserve sufficient capacity thereon for transmission of the flow, and a probability measure indicative of a likelihood of success of an attempt to identify and reserve sufficient capacity for the flow.