Dynamic bandwidth management using signaling protocol and virtual concatenation

In a data communication system comprising a first switching circuit and also comprising a second switching circuit, a method for changing the bandwidth of a circuit switched connection between the first and second switching circuits without taking down the connection comprising:

• issuing a connection create request effective during a first time period and a connection modify command effective during a second time period;
• responding to the connection create request during the first time period to reserve first resources at a first bandwidth for transmitting the data across the first switching circuit at the first bandwidth and to launch a first path setup message using a signaling protocol;
• responding to the connection modify command during the second time period to reserve virtually concatenated second resources at a second bandwidth greater than the first bandwidth for transmitting the data across the first switching circuit at the second bandwidth and to launch a second path setup message using the signaling protocol;
• responding to the first path setup message during the first time period to reserve third resources at the first bandwidth for transmitting the data across the second switching circuit at the first bandwidth and to launch a first path acknowledge message using the signaling protocol;
• responding to the second path setup message during the second time period to reserve virtually concatenated fourth resources at the second bandwidth for transmitting the data across the second switching circuit at the second bandwidth and to launch a second path acknowledge message using the signaling protocol;
• responding to the first acknowledge message during the first time period to complete a first connection across the first switching circuit using the first resources;
• responding to the second acknowledge message during the second time period to complete a second connection across the first switching circuit using the second resources;
• and
• coupling the first and second switching circuits.

A communication system including:

• a network management system;
• a digital cross-connect in communication with the network management system;
• and
• a synchronous optical network including a first add/drop multiplexer and a second add/drop multiplexer, the synchronous optical network in communication with the digital cross-connect,
• wherein the network management system uses the digital cross-connect to initiate a connection create command at the first add/drop multiplexer,
• wherein the first add/drop multiplexer reserves resources for the connection in response to the connection create command,
• wherein the digital cross-connect then transmits a path setup message to the second add/drop multiplexer using the synchronous optical network to establish a path between the first add/drop multiplexer and the second add/drop multiplexer,
• wherein the second add/drop multiplexer sends a path acknowledge to the digital cross-connect once the second add/drop multiplexer has reserved resources for the connection specified by the oath setup message,
• wherein the path acknowledge is received by the digital cross-connect and the digital cross-connect then reserves resources for the connection specified by the path setup message, and
• wherein the digital cross-connect then forwards the path acknowledge message to the first add/drop multiplexer and the first add/drop multiplexer then completes the connection.

In a data communications system, a method for changing the bandwidth of an existing circuit switched connection between a first switching circuit and a second switching circuit without taking down the existing connection, the method comprising:

• launching a connection modify command from a network management system via a digital cross-connect to the first switching circuit;
• reserving first additional resources for the existing connection at the first switching circuit and launching a path setup message from the first switching circuit to the digital cross-connect in response to receiving the connection modify command at the first switching circuit;
• reserving second additional resources for the existing connection at the digital cross-connect and forwarding the path setup message to the second switching circuit in response to receiving the path setup message at the digital cross-connect;
• reserving third additional resources for the existing connection at the second switching circuit, virtually combining the third additional resources with the existing connection at the second switching circuit, and launching a path acknowledge message to the digital cross-connect in response to receiving the path setup message at the second switching circuit;
• virtually combining the second additional resources with the existing connection at the digital cross-connect and forwarding the path acknowledge message to the first switching circuit in response to receiving the path acknowledge message at the digital cross-connect;
• and
• virtually combining the first additional resources with the existing connection at the first switching circuit in response to receiving the path acknowledge message at the first switching circuit.