Method of reducing the amount of information included in topology database update messages in a data communications network

For use at each network node in a communications network wherein each said node maintains a topology database comprising individual records defining individual network resources by sending topology database update messages to adjacent nodes and receiving topology database update messages from adjacent nodes, each of said messages containing information about at least one network resource defined in the topology database of a sending node, a method of reducing the amount of information that must be sent to an adjacent node upon establishment of a connection with that node, said method comprising the steps of:

• assigning a unique sequence number to each topology database update message generated by the sending node;
• maintaining a record of the sequence number of the most recent topology database update message sent to each adjacent node and, for each individual resource defined in the topology database, the sequence number of the most recent topology database update message including that resource;
• upon establishment of a connection with an adjacent node,
• receiving, from said adjacent node, the sequence number of the most recent topology database update message actually received by that node,
• comparing the sequence number received from that node with the sequence number assigned to the individual resources defined in the topology database;
• and
• including in the topology database update message to be sent to the adjacent node only those resources having a recorded sequence number newer than the sequence number of the most recent topology database update message reported as having been received by said adjacent node.

For use at each network node in a communications network wherein each said node maintains a topology database comprising individual records defining individual network resources and wherein said node is capable of sending topology database update messages to adjacent nodes and receiving topology database update messages from adjacent nodes, each of said messages containing information about at least one network resource defined in the topology database of a sending node, a method of reducing the amount of information that must be sent to an adjacent node to provide updates about the network resources defined at the sending node, said method comprising the steps of:

• assigning a unique sequence number to each topology database update message generated by the sending node;
• maintaining a record of the sequence number of the most recent topology database update message sent to each adjacent node and, for each individual resource defined in the topology database, the sequence number of the most recent topology database update message including that resource;
• upon establishment of a need to send a topology database update message to adjacent nodes, comparing the sequence number of the most recent topology database update message previously sent to each node with the sequence number assigned to the individual resources defined in the topology database;
• and
• including in the topology database update message to be sent to the each node only those resources having a recorded sequence number newer than the sequence number of the most recent topology database update message previously sent to the same node.

For use at each network node in a communications network wherein each said node maintains a topology database comprising individual records defining individual network resources and wherein said node is capable of sending topology database update messages to adjacent nodes and receiving topology database update messages from adjacent nodes, each of said messages containing information about at least one network resource defined in the topology database of a sending node, a method of reducing the amount of information that must be sent to an adjacent node when a connection between said nodes is re-established, said method comprising the steps of:

• causing each node
• to assign a unique sequence number to each topology database update message generated by a sending node, and
• to maintain a record of the sequence number of the most recent topology database update message sent to each adjacent node and, for each individual resource defined in the topology database, the sequence number of the most recent topology database update message sent to any adjacent node including information about that resource;
• upon establishment of a connection between two nodes;
• causing a first of said nodes to send a request for a topology database update message to the second of said nodes, said request containing the sequence number of the most recent topology database update message previously received from the second node of a unique sequence number if no topology database update messages have been received from the second node,
• causing the second of said nodes to respond either with a topology database update message including only individual records for network resources having recorded sequence numbers newer than the sequence number received from said first node or, if the unique sequence number was received, with a topology database update message including the individual records for all network resources in the topology database of said second node.