Patent ID: 6222842
Filing Date: 2001-04-24
Classification: H04L,H04Q

Abstract:
A system in which a plurality of entities are connected to a network and can exchange messages across virtual circuits setup over the network between said entities, each entity having an operative high-level address on the network, and each said entity comprising:high-level messaging means for handling message transmission and receipt on the basis of said high-level addresses, said high-level messaging means comprising means for including in outgoing ones of said messages the operative high-level address of the entity as a source identifier and the operative high level-address of the intended recipient entity as a destination identifier, and means for filtering incoming ones of said messages according to the destination identifier contained in the message;virtual-circuit means for providing virtual circuits between the entity and other said entities, there being a respective virtual circuit for each different destination identifier in use; andintermediate means for passing an outgoing message from said high-level messaging means to that one of the virtual circuits provided by the virtual circuit means which corresponds to the destination identifier of the message;wherein each of a first and a second said entity has a plurality of virtual high-level addresses associated with it that are different from said operative high-level address of the entity, said virtual high-level addresses being usable by the messaging means of said first and second entities as destination identifiers in outgoing messages; andwherein between said intermediate means of said first and second entities, there are provided address-changing means responsive to each of at least some of said messages sent between these entities with a said virtual high-level address as its destination identifier to change that address to the said operative high-level address of the corresponding entity, and to change the operative high-level address provided as the source identifier of the message into one of the said virtual high-level addresses associated with the sending entity in dependence on the virtual high-level address initially provided as the destination identifier of the same message, in this way both said destination identifier and said source identifier being changed in each of said at least some of said messages.