Policy based system management

A method of management of concurrent sessions within a networked electronic system to facilitate expansion of the networked system, comprising defining a model of the system to be managed, defining policies, which policies are applicable to components of the model, wherein system components are modelled as entities in the model with hierarchical relationships between the entities, which entities each comprise physical or non-physical objects in the system, wherein each policy includes an identifier and comprises one or more time-sensitive rules, which rules describe one or more actions to be taken if certain pre-defined conditions exist as an event, wherein the policies provide guidelines for how the entities should be managed in response to interactions between the entities within the system, the policies then being enforced in response to such interactions between entities within the system, characterised in that the networked electronic system comprises multiple servers, the model being split into parts such that policy information for a given entity is held on a nominated one of the multiple servers, with the other servers being informed of where to find the policy information, determination of which policies to apply to a given request being made by a policy checker, which policies are then executed and applied to one or more entities within the networked system.