METHOD OF CONTROLLING LIMITED RESOURCE SESSIONS IN A DATA COMMUNICATIONS NETWORK

The links in a data communications network following Systems Network Architecture may be categorized as limited resource links if those links are shared access transport facilities, such as a switched telephone network, X.21, X.25 or token ring local area network facilities. In setting up LU-LU sessions between network users, a limited resource session identifier field is set to a specific value if any of the links in the session data path is defined as a limited resource link. In a conversation between two users ends (20, 22), the primary logical unit (32) responds by determining whether the session has been identified as a limited resource session. If it has, the primary logical unit initiates action to deactivate the session without waiting for network control operation action. Allowing the primary logical unit to deactivate a limited resource session assures that the limited resource link or links will not remain allocated needlessly to an unused session.