1. A system comprising a network of network elements, each network element supporting at least one respective process, the network further comprising a data store associated with a data store manager, wherein the data store maintains a first model of said system, said first model representing an actual state of the system and including data identifying each of said network elements and each of said at least one respective processes that is instantiated on respective network elements, said first model further including data representing the actual state of said at least one respective process, and wherein the data store maintains a second model of said system, said second model being independent of said first model and representing a planned state of the system, said second model including data identifying each of said network elements and, in respect of each network element, at least one of said at least one respective processes that is planned to be instantiated on the respective network element, the data store manager being arranged to cause the respective network elements to instantiate each respective process that said second model identifies as being planned to be instantiated on the respective network element but is not yet instantiated on the respective network element, and at least some of said processes being arranged to communicate to said data store manager data representing their respective state, the data store manager, upon receipt of said data from said at least some processes, being arranged to update said first model in accordance with said received data, wherein the data store manager is arranged to perform a persistent search of the data store based on respective search criteria provided by one or more of said processes.