Sridhar N Alagar

US Patent:

5699349, Dec 16, 1997

Filed:

Jun 14, 1996

Appl. No.:

8/665177

Inventors:

Will L. Russ - Dallas TX
Sridhar Alagar - Dallas TX
Si Bad - Richardson TX
Lee D. Bengston - Murphy TX
Tim T. Chao - Plano TX
Fred Ellefson - Allen TX
Bryan J. McGlade - Plano TX
Mark W. Sees - Plano TX
Clint Allen Wagner - Allen TX

Assignee:

MCI Communications Corp. - Washington DC

International Classification:

H04J 116

US Classification:

370248

Abstract:

A system and method for restoring communication between at least one pair of nodes in a network. Distributed intelligence is provided by messaging between adjacent nodes in the network. The messages in combination with user-configurable timers and rules provide fault isolation, forward flooding, reverse linking and connection.

US Patent:

6404733, Jun 11, 2002

Filed:

Sep 8, 1998

Appl. No.:

09/148943

Inventors:

Jasvantrai C. Shah - Richardson TX
John David Allen - Garland TX
Sridhar Alagar - Dallas TX
Bryan McGlade - Plano TX
Hal Badt - Richardson TX

Assignee:

MCI WorldCom, Inc. - Washington DC

International Classification:

H04L 100

US Classification:

370216, 370241

Abstract:

In a telecommunications network provisioned with a distributed restoration scheme, to determine the reactions and responses of the network while the network is âliveâ or operational, an exercise information message is provided to the network for presenting a simulated failure or failures thereto. This exercise information message is broadcast to all of the nodes of the network so that every node is aware of the simulated failure scenario. Modified DRA messages that indicate that they are exercise only messages are used by the nodes for executing the exercise restoration process. Such exercise restoration process will proceed as if an actual failure has occurred with the notable exception that no actual cross-connections will be made. Certain functionalities are provisioned to the nodes to allow the exercise restoration process to be aborted if a real failure is detected or upon the expiration of a timer. The exercise restoration process can also be terminated by a command from the network management.

US Patent:

6456589, Sep 24, 2002

Filed:

Sep 8, 1998

Appl. No.:

09/149590

Inventors:

Jasvantrai C. Shah - Richardson TX
Lee D. Bengston - Murphy TX
Mark W. Sees - Allen TX
Sridhar Alagar - Dallas TX
Bryan McGlade - Plano TX
Hal Badt - Richardson TX

Assignee:

WorldCom, Inc. - Clinton MS

International Classification:

G01R 3108

US Classification:

370228, 370248

Abstract:

In a telecommunications network provisioned with different types of restoration processes, to ensure that the operation of one restoration process does not infringe upon other nodes that are actively executing a different restoration process, a request is sent by one of the restoration processes, under the guise of the operation system that oversees that process, to the operation system that oversees the other restoration process. The controller of the nodes that are performing the other restoration process, in receipt of the request, sends a disable restoration process message to those nodes under its control. Each of those nodes, upon receipt of the disable restoration process message, would disable the restoration process it is provisioned with so long as it is not actively engaging in that restoration process. If it is, it will continue to execute that restoration process until a safe stop point is reached, at which time it ceases that restoration process. Upon cessation of the particular restoration process, the node sends an acknowledge message to its controller, which, when in receipt of such acknowledge message from all of the nodes under its control, sends a disable acknowledged message to the controller of the first restoration process informing the latter that the nodes under its control can now be operated using the first restoration process.

US Patent:

6496476, Dec 17, 2002

Filed:

Sep 11, 1998

Appl. No.:

09/151320

Inventors:

Sridhar Alagar - Sunnyvale CA
Bryan J. McGlade - Balwyn North, AU

Assignee:

WorldCom, Inc. - Clinton MS

International Classification:

G01R 3108

US Classification:

370228

Abstract:

In a path-based distributed restoration algorithm provisioned telecommunications network, the origin and destination nodes of a failed path are apprised of the portions of the path that remain intact by âreuseâ messages that are sent from the custodial nodes that are adjacent to the failure. As each reuse message reaches an intermediate node, the node ID of the intermediate node is appended to a field of the message so that, as the reuse messages are propagated along the intact portions of the failed path, a cumulative list of nodes that are encountered by the messages passing from the custodial nodes to the origin and destination nodes is set forth. Thus, the origin/destination node, when in receipt of a reuse message, can read from the field that has the cumulative list of nodes a description of the intact portions remaining from the original path. These intact portions are preferably used only for restoring of the same path that included the portions prior to failure and are not available for restoring any other paths that happened to fail simultaneously.

US Patent:

6507561, Jan 14, 2003

Filed:

Mar 11, 1998

Appl. No.:

09/038531

Inventors:

Paul T. Baniewicz - Plano TX
Ashley W. Brimmage - Plano TX
Sridhar Alagar - Richardson TX
S. Hal Badt - Richardson TX
Frederick R. Ellefson - Allen TX
Bryan J. McGlade - Plano TX

Assignee:

WorldCom, Inc. - Clinton MS

International Classification:

G01R 3108

US Classification:

370216, 370242, 714 2

Abstract:

A network wherein a plurality of links connects a plurality of nodes such as cross-connects in a communication circuit network with paths interconnecting the nodes, and with there being spare capacity between a sufficient number of nodes to accommodate at least some rerouting of traffic immediately upon detection of a break in a traffic span in the network so as to restore circuit continuity within a predetermined maximum time using an improved failure detection, isolation, and recovery scheme.

US Patent:

6512740, Jan 28, 2003

Filed:

Nov 3, 1998

Appl. No.:

09/185190

Inventors:

Paul T. Baniewicz - Plano TX
Ashley W. Brimmage - Plano TX
Sridhar Alagar - Richardson TX
Frederick R. Ellefson - Allen TX
Bryan J. McGlade - Plano TX

Assignee:

Alcatel - Richardson TX

International Classification:

H04L 100

US Classification:

370216, 370522, 34082501, 714 4

Abstract:

A network wherein a plurality of links connects a plurality of nodes such as cross-connects in a communication circuit network with paths interconnecting the nodes, and with there being spare capacity between a sufficient number of nodes to accommodate at least some rerouting of traffic immediately upon detection of a break in a traffic span in the network so as to restore circuit continuity within a predetermined maximum time using an improved failure detection, isolation, and recovery.

US Patent:

7046619, May 16, 2006

Filed:

Nov 6, 2001

Appl. No.:

10/045955

Inventors:

Sridhar Alagar - Sunnyvale CA, US
Brian Pheiffer - Santa Jose CA, US
Rohit Sharma - Sunnyvale CA, US
Stephane St. Laurent - Santa Clara CA, US
Holden D. Jessup - Palo Alto CA, US
Rainer Iraschko - Sunnyvale CA, US

Assignee:

CIENA Corporation - Linthicum MD

International Classification:

H04L 1/00

US Classification:

370216, 370252, 370352, 370389, 714 4

Abstract:

A system for use in a bi-directional path switched ring network for detecting a failed optical path and establishing a protection path so as to allow signals from the failed optical path to be re-routed via the protection path is provided. According to one aspect of the system, upon detecting a failure relating to an optical path, the destination node generates a connection request message for transmission to the source node. The connection request message is passed to the source node via one or more intermediate nodes, if any. Each intermediate node examines the connection request message accordingly reserves the requisite wavelength from the protection capacity so as to allow signals from the failed optical path to be re-routed. Upon receiving the connection request message, the source node readies its switching equipment to re-route signals from the failed optical path and generates an acknowledgment message and propagates it back to the destination node via the intermediate nodes. The intermediate nodes and the destination node, upon receipt of the acknowledgement message, also ready their respective switching equipment to carry the re-routed signals via the previously reserved wavelength from the protection capacity.

US Patent:

57815356, Jul 14, 1998

Filed:

Jun 14, 1996

Appl. No.:

8/665177

Inventors:

Will L. Russ - Dallas TX
Sridhar Alagar - Dallas TX
Sig Harold Badt - Richardson TX
Lee D. Bengston - Murphy TX
Tim T. Chao - Plano TX
Fred Ellefson - Allen TX
Bryan J. McGlade - Plano TX
Mark W. Sees - Plano TX
Clint Allen Wagner - Allen TX

Assignee:

MCI Communications Corp. - Washington DC

International Classification:

H04J 116

US Classification:

370248

Abstract:

A system and method for restoring communication between at least one pair of nodes in a network. Distributed intelligence is provided by messaging between adjacent nodes in the network. The messages in combination with user-configurable timers and rules provide fault isolation, forward flooding, reverse linking and connection.