Derek H Pitcher

US Patent:

6370142, Apr 9, 2002

Filed:

Apr 2, 1997

Appl. No.:

08/832042

Inventors:

Derek Pitcher - Newark CA
Kishore K. Seshadri - Redwood City CA
Daniel A. Simone - Mountain View CA

Assignee:

Nortel Networks Limited - St. Laurent

International Classification:

H04L 1228

US Classification:

370390, 370401, 370432

Abstract:

A method and apparatus for performing per-port Internet Protocol (IP) multicast pruning, proxying of IP multicast group membership reports, and generating pseudo membership queries for determining IP multicast group membership are provided. A switch may implement per-port IP multicast pruning by establishing a mapping of IP multicast groups to its ports. The mapping is based upon membership reports received from each end-station participating in an IP multicast group. Based upon the mapping, the switch forwards IP multicast packets only to those of the end-stations that are participating in the IP multicast group addressed. Once per-port IP multicast pruning is implemented, multicast routers must process membership reports from all end-stations participating in an IP multicast group. To reduce this burden, a switch may act as a proxy device. The switch receives a membership report identifying an IP multicast group.

US Patent:

6427185, Jul 30, 2002

Filed:

Jul 17, 1997

Appl. No.:

08/896485

Inventors:

Randy Ryals - Menlo Park CA
Jeffrey Prince - Sunnyvale CA
H. Earl Ferguson - Los Altos CA
Mike K. Noll - San Jose CA
Derek H. Pitcher - Newark CA

Assignee:

Nortel Networks Limited - St. Laurent

International Classification:

G06F 1208

US Classification:

711100, 711146

Abstract:

A method and apparatus for managing the flow of data within a switching device is provided. The switching device includes network interface cards connected to a common backplane. Each interface card is configured to support the maximum transfer rate of the backplane by maintaining a âpendingâ queue to track data that has been received but for which the appropriate routing destination has not yet been determined. The switching device includes a switch controller that maintains a central card/port-to-address table. When an interface card receives data with a destination address that is not known to the interface card, the interface card performs a direct memory access over a bus that is separate from the backplane to read routing data directly from the central table in the switch controller. Each interface card builds and maintains a routing information table in its own local memory that only includes routing information for the destination addresses that the interface card is most likely to receive.

US Patent:

6671279, Dec 30, 2003

Filed:

Feb 24, 1999

Appl. No.:

09/257075

Inventors:

Jim Mangin - San Ramon CA
Mohan Kalkunte - Sunnyvale CA
Derek Pitcher - Los Altos CA

Assignee:

Nortel Networks Limited - St. Laurent

International Classification:

H04L 1228

US Classification:

3703955, 370401

Abstract:

A technique for establishing a shortcut Virtual Channel Connection (VCC) in a Multi-Protocol Over ATM (MPOA) system detects a packet flow, and then determines whether to establish the shortcut VCC based upon an expected MPOA server response time. Specifically, an expected MPOA server response time is determined based upon an MPOA server response time history. The expected MPOA server response time is then compared to a predetermined MPOA server response time threshold to determine whether the expected MPOA server response time is within the predetermined MPOA server response time threshold. The shortcut VCC is established if the expected MPOA server response time is within the predetermined MPOA server response time threshold. Upon establishing the shortcut VCC, the MPOA server response time history is updated to reflect an actual MPOA server response time incurred when establishing the shortcut VCC.

US Patent:

6747951, Jun 8, 2004

Filed:

Sep 20, 1999

Appl. No.:

09/399548

Inventors:

Mohan V. Kalkunte - Sunnyvale CA
James L. Mangin - San Ramon CA
Derek H. Pitcher - Los Altos CA

Assignee:

Nortel Networks Limited - St. Laurent

International Classification:

H04L 1228

US Classification:

370235, 370351, 3703955, 370401

Abstract:

A technique for dynamically adjusting the aging time of a shortcut virtual circuit connection (VCC) in a Multi-protocol over ATM (MPOA) client based on one or more factors. In one embodiment, a method of dynamically adjusting aging time of a shortcut VCC includes detecting a packet flow between a source and a destination, establishing a shortcut VCC between the source and destination, and adjusting an aging time of the shortcut VCC in response to the number of VCCs available by the MPOA client. In other embodiment, the aging time is dynamically adjusted based on the VCC threshold level, the protocol of the flow, and/or the application type of the flow.

US Patent:

6760336, Jul 6, 2004

Filed:

Feb 18, 1999

Appl. No.:

09/252430

Inventors:

James Mangin - San Ramon CA
Mohan Kalkunte - Sunnyvale CA
Derek Pitcher - Los Altos CA

Assignee:

Nortel Networks Limited - St. Laurent

International Classification:

G06F 1516

US Classification:

37039521, 37039552, 709228, 709238

Abstract:

A method and a system for improving communication performance between nodes in a network is disclosed. In one embodiment, the system includes routers, switches, and a communication interface. The communication interface detects a communication flow between a source and a destination in response to a flow criteria. Upon detecting the communication flow, the communication interface issues a resolution request for identifying data path. After receipt of a response to the resolution request, multiple connections between switches are established in response to levels of quality of service (QoS).

US Patent:

7031296, Apr 18, 2006

Filed:

Dec 27, 2002

Appl. No.:

10/330640

Inventors:

Randy Ryals - Menlo Park CA, US
Jeffrey Prince - Sunnyvale CA, US
H. Earl Ferguson - Los Altos CA, US
Mike K. Noll - San Jose CA, US
Derek H. Pitcher - Newark CA, US

Assignee:

Nortel Networks Limited - St. Laurent

International Classification:

H04L 12/00

US Classification:

370351, 370355, 370362, 370392

Abstract:

A method and apparatus for managing the flow of data within a switching device is provided. The switching device includes network interface cards connected to a common backplane. Each interface card is configured to support the maximum transfer rate of the backplane by maintaining a “pending” queue to track data that has been received but for which the appropriate routing destination has not yet been determined. The switching device includes a switch controller that maintains a central card/port-to-address table. When an interface card receives data with a destination address that is not known to the interface card, the interface card performs a direct memory access over a bus that is separate from the backplane to read routing data directly from the central table in the switch controller. Each interface card builds and maintains a routing information table in its own local memory that only includes routing information for the destination addresses that the interface card is most likely to receive.

US Patent:

7310664, Dec 18, 2007

Filed:

Feb 6, 2004

Appl. No.:

10/773487

Inventors:

Shehzad T. Merchant - Mountain View CA, US
Manish M. Rathi - San Jose CA, US
Victor C. Lin - Fremont CA, US
Vipin K. Jain - Santa Clara CA, US
Jia-Ru Li - San Jose CA, US
Amit K. Maitra - Cupertino CA, US
Matthew R. Peters - Santa Cruz CA, US
Derek H. Pitcher - Los Altos CA, US
Balaji Srinivasan - Fremont CA, US

Assignee:

Extreme Networks - Santa Clara CA

International Classification:

G06F 15/173

US Classification:

709220

Abstract:

A network switch having a unified, adaptive management paradigm for wireless network devices is disclosed. The switch includes configurable ports for connecting devices. A software application running on the switch allows a network administrator to selectively configure each port to support either a wired device or wireless device. Configuration information and software images that are needed for operation of the wireless device are associated with the port. When a wireless device is first plugged into the switch port, it downloads its configuration directly from the switch port. By storing the configuration information and images at the switch and automatically downloading them to the wireless devices, the task of configuring the devices is greatly simplified for the network administrator. This is particularly advantageous in heterogeneous network environments that support both wired and wireless devices, and where wireless device are readily moved to different ports.

US Patent:

RE40467, Aug 26, 2008

Filed:

Feb 3, 2006

Appl. No.:

11/347786

Inventors:

Randy Ryals - Menlo Park CA, US
Jeffrey Prince - Sunnyvale CA, US
H. Earl Ferguson - Los Altos CA, US
Mike K. Noll - San Jose CA, US
Derek H. Pitcher - Newark CA, US

Assignee:

Nortel Networks Limited - St. Laurent, Quebec

International Classification:

H04L 12/00

US Classification:

370351, 370355, 370359

Abstract:

A method and apparatus for managing the flow of data within a switching device is provided. The switching device includes network interface cards connected to a common backplane. Each interface card is configured to support the maximum transfer rate of the backplane by maintaining a “pending” queue to track data that has been received but for which the appropriate routing destination has not yet been determined. The switching device includes a switch controller that maintains a central card/port-to-address table. When an interface card receives data with a destination address that is not known to the interface card, the interface card performs a direct memory access over a bus that is separate from the backplane to read routing data directly from the central table in the switch controller. Each interface card builds and maintains a routing information table in its own local memory that only includes a routing information for the destination addresses that the interface card is most likely to receive.