Method of maintaining a topology database

US4827411A · kind A · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Andrew Hilliard Arrowood · Raleigh, US
• Alan E. Baratz · Los Altos Hills, US
• Philip F. Chimento, Jr. · Rockville, US
• John E. Drake · Pittsburgh, US
• John L. Eisenbies · Raleigh, US
• James P. Gray · Chapel Hill, US
• Karla J. Norsworthy · Raleigh, US
• Diane P. Pozefsky · Chapel Hill, US

Key dates

• Filing date: Jun 15, 1987
• Grant date: May 2, 1989
• Expiry date: Jun 15, 2007

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S707/99957
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

Each network node in a communications network maintains its own copy of the network topology database defining network resources. Each resource record contains a "timer" field which is initially set to a maximum value but which may be decremented on a daily basis. If the timer field is decremented to zero without being reset, the node unilaterally removes the resource record from its copy of the database. The timer field will normally reach zero only for obsolete resource records since each network node responsible for a resource broadcasts a timer-resetting message for the resource (1) each time the resource status changes, (2) when the node first joins or rejoins the network, and (3) on a periodic (weekly) basis regardless of whether conditions (1) or (2) have occurred.