Connection caching of traffic adaptive dynamic virtual circuits

摘要

Local Area Networks may be interconnected using X.25 networks. If only the OSI connectionless network protocol (CLNP) is supported on the LANs, then this same protocol must operate above X.25, using the X.25 service as a virtual data link layer. The intermediate systems in this case must support CLNP packet delivery over X.25 virtual circuits, implementing the ISO 8473/DAD1 subnetwork dependent convergence function to resolve the differences which exist between the OSI connectionless network service and the connection-oriented service offered by the X.25 subnetwork. This means that the main functionality of this subnetwork dependent convergence function is to open virtual circuits on packet demand and to close them when no traffic has occurred for a period of time. This paper describes an algorithm, which calculates such a time period by taking into account the current traffic load, the connection cost and the maintenance cost.