Thomas J Manning

US Patent:

6426957, Jul 30, 2002

Filed:

Dec 11, 1998

Appl. No.:

09/209526

Inventors:

Stephen A. Hauser - Burlington MA
Stephen A. Caldara - Sudbury MA
Thomas A. Manning - Northboro MA

Assignee:

Fujitsu Network Communications, Inc. - Richardson TX
Fujitsu Limited - Kanagawa-ken

International Classification:

H04L 1228

US Classification:

370413, 3703954, 370389

Abstract:

An asynchronous transfer mode (ATM) based service consolidation switch ( ) includes an input/output module ( ) having a to-switch port (TSPP) processor ( ) and a from-switch port processor (FSPP) ( ). The TSPP ( ) and the FSPP ( ) communicate with a bandwidth arbiter ( ), multipoint topology controllers ( ), and a data crossbar ( ) on a switch control module ( ). The TSPP ( ) receives traffic over links for conversion into an internal cell format. Internal cells are buffered until allowed to transfer to an appropriate FSPP ( ). Multipoint topology controllers ( ) performs translations for internal switch flow control through interactions between the TSPPs ( ), FSPPs ( ), and the bandwidth arbiter ( ). The bandwidth arbiter ( ) performs appropriate bandwidth arbitration to allow internal cells to flow from TSPPs ( ) to FSPPs ( ) over the data crossbar ( ).

US Patent:

6628668, Sep 30, 2003

Filed:

Mar 16, 1999

Appl. No.:

09/270950

Inventors:

Peter Hutzli - Acton MA
David N. Peck - Northbridge MA
Thomas A. Manning - Northboro MA

Assignee:

Fujitsu Network Communications, Inc. - Richardson TX

International Classification:

H04J 316

US Classification:

370468, 37039521, 37039541

Abstract:

A system for allocating bandwidth in a network element. The system determines whether a bandwidth allocation request is associated with a delay sensitive connection type. If so, the system selects a bandwidth allocation algorithm from a first set of bandwidth allocation algorithms. Otherwise, the system selects a bandwidth allocation algorithm from a second set of bandwidth allocation algorithms. The size of the bandwidth allocation request may be examined when selecting which bandwidth allocation algorithm to use. The system may round up the size of the bandwidth allocation request to a predetermined value. The selected bandwidth allocation algorithm may reserve slots in a bandwidth allocation table. Reserved slots that are equally spaced in the bandwidth allocation table avoid undue delays in servicing an associated connection. A binary tree representation of the table is described, wherein leaves of the binary tree correspond to individual table slots.

US Patent:

59783591, Nov 2, 1999

Filed:

Jul 18, 1996

Appl. No.:

8/683348

Inventors:

Stephen A. Caldara - Sudbury MA
Stephen A. Hauser - Burlington MA
Thomas A. Manning - Northboro MA

Assignee:

Fujitsu Network Communications, Inc. - Richardson TX
Fujitsu Limited - Kawasaki

International Classification:

H04L 1256

US Classification:

370236

Abstract:

A system is disclosed for eliminating cell loss through the use of flow control of both allocated and dynamic bandwidth. When output buffers in the switch become filled to a predetermined threshold level a feedback message is provided to input buffers to prevent transmission of cells from the input buffers to the output buffers. In order to provide connection and traffic type isolation the buffers are grouped into queues and flow control may be implemented on a per queue basis. The feedback message is a digital signal including an ACCEPT/REJECT message and a NO-OP/XOFF message. An XOFF message can be received while transmitting via allocated bandwidth or dynamic bandwidth. In particular, an XOFF (allocated) message may be received with regard to allocated bandwidth and an XOFF (dynamic) message may be received with regard to dynamic bandwidth. When ACCEPT is received by the requesting input queue the cell is transferred to the output queue. When REJECT is received by the requesting queue the cell is not transferred.

US Patent:

59960191, Nov 30, 1999

Filed:

Jul 18, 1996

Appl. No.:

8/683127

Inventors:

Stephen A. Hauser - Burlington MA
Richard G. Bubenik - St. Louis MO
Stephen A. Caldara - Sudbury MA
Michael E. Gaddis - Defiance MO
Thomas A. Manning - Northboro MA
James M. Meredith - Westford MA
Raymond L. Strouble - Westford MA

Assignee:

Fujitsu Network Communications, Inc. - Richardson TX
Fujitsu Limited - Kawasaki

International Classification:

H04J 322

US Classification:

709235

Abstract:

Methods and apparatus for scheduling cell transmission over a network link by a switch. The switch includes a plurality of queues associated with each link. Lists of queues are maintained for each link. In one embodiment, each link is associated with more than one type of list (with the list type corresponding to a scheduling category) and more than one prioritized list of each type (with the priority of the list corresponding to a quality of service). The scheduling lists are accessed to permit cell transmission from a queue contained therein in a predetermined sequence as a function of scheduling category, priority within a particular scheduling category and whether the bandwidth requirement for the particular scheduling category has been met. With this arrangement, maximum permissible delay requirements for each scheduling category are met.

US Patent:

61157481, Sep 5, 2000

Filed:

Jul 18, 1996

Appl. No.:

8/683448

Inventors:

Stephen A. Hauser - Burlington MA
Stephen A. Caldara - Sudbury MA
Thomas A. Manning - Northboro MA

Assignee:

Fujitsu Network Communications, Inc. - Richardson TX
Fujitsu Limited - Kawasaki

International Classification:

G06F 1516

US Classification:

709234

Abstract:

In a link-level flow controlled system, a method and apparatus providing the ability to partition a buffer resource among multiple prioritized buffer subsets through definition of at least one threshold, the buffer resource being shared by a plurality of connections. Different category of service levels, in terms of delay bounds, are thus enabled. The presently disclosed link-level flow controlled system provides for zero cell loss. The shared buffer resource is divided among N priority pools, defined by N-1 threshold levels, each priority pool attributable to a respective category of service. Link-level counters and registers, disposed in a transmit element, as well as an indication of priority level associated with each connection, are employed in realizing the shared buffer resource.

US Patent:

58727698, Feb 16, 1999

Filed:

Jul 18, 1996

Appl. No.:

8/683447

Inventors:

Stephen A. Caldara - Sudbury MA
Stephen A. Hauser - Burlington MA
Thomas A. Manning - Northboro MA
Raymond L. Strouble - Westford MA

Assignee:

Fujitsu Network Communications, Inc. - Richardson TX
Fujitsu Limited - Kawasaki

International Classification:

H04L 1256

US Classification:

370230

Abstract:

A linked-list structure and method for use in an ATM network switch capable of adaptively providing highly efficient, and thus low cost, integrated services therein. The linked-list structure involves the creation of a list having pointers to a subsequent linked list as list entries. Within the subsequent linked list, each entry can be a pointer to a further linked list. The structure can be expanded to further levels of linked lists as required. Bandwidth distribution is thus achieved among list members at each level. The linked-list structure is employed in the present switch, which includes an input port processor, a bandwidth arbiter, and an output port processor, for switch bandwidth scheduling for both point-to-point, multipoint-to-point and point-to-multipoint cell transfers from the input port processor, and for output link scheduling at the output port processor.

US Patent:

60761121, Jun 13, 2000

Filed:

Mar 9, 1999

Appl. No.:

9/265440

Inventors:

Stephen A. Hauser - Burlington MA
Stephen A. Caldara - Sudbury MA
Thomas A. Manning - Northboro MA

Assignee:

Fujitsu Network Communications, Inc. - Richardson TX
Fujitsu Limited - Kawasaki

International Classification:

G06F 1300

US Classification:

709234

Abstract:

In a link-level flow controlled system, a method and apparatus providing the ability to partition a buffer resource among multiple prioritized buffer subsets through definition of at least one threshold, the buffer resource being shared by a plurality of connections. Different category of service levels, in terms of delay bounds, are thus enabled. The presently disclosed link-level flow controlled system provides for zero cell loss. The shared buffer resource is divided among N priority pools, defined by N-1 threshold levels, each priority pool attributable to a respective category of service. Link-level counters and registers, disposed in a transmit element, as well as an indication of priority level associated with each connection, are employed in realizing the shared buffer resource.

US Patent:

59827718, Nov 9, 1999

Filed:

Jul 18, 1996

Appl. No.:

8/683154

Inventors:

Stephen A. Caldara - Sudbury MA
Stephen A. Hauser - Burlington MA
Thomas A. Manning - Northboro MA
Raymond L. Strouble - Westford MA

Assignee:

Fujitsu Network Communications, Inc. - Richardson TX
Fujitsu Limited - Kawasaki

International Classification:

H04L 1256

US Classification:

370389

Abstract:

A method and apparatus is disclosed for allocating bandwidth within a network switch having a plurality of input ports coupled to a plurality of output ports through a switch fabric to assure that a minimum bandwidth is allocated for predetermined scheduling lists. A switch allocation table is provided for each of a plurality of input ports. Each switch allocation table is organized as a circular table which is sequentially indexed via an associated index counter. Respective entries in the switch allocation table comprise scheduling list numbers which serve to identify cells requiring switch bandwidth. The respective index counters are synchronized such that all switch allocation tables have a corresponding entry selected. The amount of bandwidth and delay through the network switch is controlled for each of the scheduling lists based upon the number and spacing of entries in the respective switch allocation table. Latency through the network switch is significantly reduced via the use of a pace counter and a pace limit which, in cooperation with the switch allocation table, determine whether a cell associated with a particular scheduling list may be dispatched through the switch fabric for transmittal onto a network link by at least one of the output ports.