Abstract: The present invention relates to the application of Distributed Ledger Technology (DLT) to the field of software defined networking in a system and method for providing an end-to-end network comprising a plurality of software defined networks (SDNs) wherein each of the plurality of software defined networks is controlled by a software defined network controller (SDNC), the system comprising: a distributed ledger, wherein the distributed ledger is associated with a Smart Contract, wherein the Smart Contract comprises software code configured to control access by SDNCs to the distributed ledger by assessing whether a business entity and an SDNC operated by the business entity, requesting access to the distributed ledger, meet predefined trust criteria.

Abstract: A method of constructing a forwarding database for a data communications network comprising a plurality of network components and supporting at least first and second topologies having one or more common network components is described. The forwarding database includes a plurality of entries providing forwarding information for data destined for a related network component. The method comprises the step, performed at a constructing network component, of deriving topology dependent forwarding information for data destined for a network component. The method further comprises the step of including the topology dependent forwarding information at the related forwarding database entry.