Connection caching of traffic adaptive dynamic virtual circuits

ABSTRACT

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.

REFERENCES

• 1: CCITT, Red Book, Vol VIII - Fascicle vnI.3, Data Communication Network Interfaces, Recommendations X.20-X.25, 1985.
• 2: ISO 7498: Information Processing Systems - Open Systems Interconnection- Basic Reference Model.
• 3: ISO 7498/DAD1: Information Processing Systems - Open Systems Interconnection - Basic Reference Model - Addendum l: Connectionless-mode Transmission.
• 4: ISO/DIS 8473: Information Processing Systems - Data Communications Protocol for Providing the Connectionless-mode Network Service.
• 5: ISO 8473/DADl' Information Processing Systems - Addendum to ISO/DIS 8473 Coveting Provision of the Connectionless-mode Subnetwork Service.
• 6: ISO 8648' Information Processing Systems - Data Communications Internal Organization of the Network Layer.

INDEX TERMS

Primary Classification:
  F. Theory of Computation
  F.2 ANALYSIS OF ALGORITHMS AND PROBLEM COMPLEXITY
      F.2.2 Nonnumerical Algorithms and Problems
          Subjects: Computations on discrete structures

Additional Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.0 General
          Subjects: Open Systems Interconnection reference model (OSI)
      C.2.5 Local and Wide-Area Networks
          Subjects: Access schemes

General Terms:
Algorithms, Design, Performance