Fujitsu Corporation

Fujitsu Network Communications, Inc.

Mark A W Stewart

David N Peck

Shantnu Sharma

Robert H Constantin

Peter W Bretschneider

Mashood Illikkal

Hong Xu

Sajin R Valoth

A system for managing data transmission from a number of queues employs a regular credit count and a history credit count for each queue. Generally, the regular credit count is used in arbitration. The count is decreased when data is transmitted from the queue and increased at given intervals if the queue is facing no transmission-blocking backpressure. The history credit count is increased in lieu of the regular credit count when transmission from the queue is blocked. Thus, the history credit count keeps track of potential transmission opportunities that would be lost due to the blocking of transmission from the queue. The history credit counts are periodically polled instead of the regular credit counts to give each queue an opportunity to catch up in its use of transmission opportunities.

Weighted credit-based arbitration using credit history

A network router generates node state advertisements identifying network links about which the router node desires to receive link state information. The node state advertisements are flooded to other routers, each of which determines whether it lies along the shortest path between the link and the originating router. Each router that lies along the shortest path maintains an association between the link and the originating router, the association indicating that link state advertisements concerning the link are to be forwarded along the path toward the originating router. Upon a change of the state of the link, each router forwards a corresponding link state advertisement to an adjacent node along the path, whereby the originating router ultimately receives the link-state advertisement.

Focused link state advertisements

A scalable protection method for connection oriented networks includes a source, a destination, and primary nodes interconnected by working path segments between the source and destination. A point-to-multipoint connection with multiple destinations and additional primary nodes is also supported. Each of a number of backup nodes is interconnected with an associated primary node by pre-provisioned shunt segments, and the backup nodes are interconnected among themselves by pre-provisioned protection path segments. Upon occurrence of a failure, the primary node upstream of the failure directs input traffic to a shunt segment, and the backup node associated with the upstream primary node directs traffic from the shunt segment to an output protection segment. Downstream of the failure, a backup node directs traffic from an input protection segment to a shunt segment, and the primary node associated with the backup node directs the traffic from the shunt segment to a downstream working segment. In this manner, traffic is routed around failures via local switching operations.

Scaleable line-based protection for connection oriented communications protocols

A highly available communications system capable of circuit reestablishment and tear-down without manual intervention. The communications system includes a plurality of nodes interconnected by a plurality of communications paths to form at least one communications network. The nodes forward control packets on the network by way of a signaling protocol employing an out-of-band control technique. At least a portion of the nodes comprises a software configuration including a topology manager and a protocol manager. The protocol manager is operative to determine whether a control path is operational and whether a data transmission channel along a corresponding data path is established. In the event the control path is not operational, the protocol manager maintains the data transmission channel along the data path so long as the channel is established. The topology manager is operative to acquire network topology data, and the protocol manager is further operative to receive the topology data, deduce network topology changes therefrom, and reestablish and tear-down communications paths interconnecting the nodes based at least in part on the deduced topology changes.

Circuit reestablishment and tear down in a highly available communications system

A method and system for forwarding packets within containers in a data communication network. Each container may include packets or additional containers. Packets/containers are stored within containers in a predetermined format that includes a Type field, a Length field and a Value field. The Type field includes an indication whether the respective packet/container is the last packet/container in the respective sequence. The Length field specifies the Length of the following Value field and the Value field comprises the payload, which may comprise additional packets or containers. A header, such as an MPLS shim header, is applied to containers to be transmitted over the network. Containers are closed and scheduled for transmission once when it is determined that the addition of a packet/container to the overall container would exceed a predetermined maximum container size or when a timer measures a predetermined time period from the arrival of the first packet within the container.

Container transport for packets in connection oriented protocols

An apparatus and method for generating via integer calculations a metric for estimating link utilization within a network device having at least one output port. The metric is determined by calculating at least three data rate link parameters for a given sampling period. The data rate link parameters include an error data rate parameter, an average data rate parameter, and a deviation data rate parameter. These parameters are determined using integer values and integer operations and may be used by a link management system for performing load balancing among a plurality of output ports and for determining whether to forward low priority data traffic via a particular output port.

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Acton, MA, United States of America

Mark A W Stewart