Nortel Networks Corporation

Analog Devices,inc.

Avaya Inc.

Da-Hai Ding

Nicholas Ilyadis

Sandeep P Golikeri

Dahong Qian

Timothy Cunningham

Marc Hertzberg

Manish Patel

Amit Burstein

Luc A Pariseau

Wayne Wong

Brenda A Thompson

Nelson Kong

A technique for multicast switching in a distributed communication system having a plurality of cooperating modules enables a module to forward multicast packets associated with a multicast stream without using a centralized module or control logic by determining all network interfaces and remote modules associated with the multicast stream and forwarding multicast packets to only those network interfaces and remote modules associated with the multicast stream. IGMP snooping may be used to determine the network interfaces and remote modules associated with the multicast stream, and may also be used to determine host addresses, router addresses, and an IGMP version for each network interface and for each remote module. In order to generate IGMP messages, the module learns a multicast device address from received IGMP messages and uses the multicast device address to send the IGMP messages. The module decides whether to send IGMP version 1 messages or IGMP version 2 messages on a particular interface based upon the IGMP version of IGMP messages received over the interface.

Multicast switching in a distributed communication system

An address reporting technique for reporting address information in a distributed communication environment retrieves locally owned address information from each of a number of distributed address databases, sorts the address information according to a predetermined sorting scheme, and reports the sorted address information. Each address database is maintained by one of a plurality of interconnected modules. A reporting module reports address information by retrieving locally owned address information from its address database, retrieves locally owned address information from each of the other interconnected modules, sorts the address information according to a predetermined sorting scheme, and reports the sorted address information. The reporting module retrieves the locally owned address information from each of the other interconnected modules by sending a request message to the other interconnected modules and receiving a response message from each of the other interconnected modules including the locally owned address information from the module. A module that receives the request message retrieves locally owned address information from its address database, formats a response message, and sends the response message to the reporting module. The reporting module may indicate a starting address, in which case each module retrieves from its address database a predetermined number of locally owned address entries starting with a first locally owned address entry that is lexicographically greater than the starting address.

System, device, and method for address reporting in a distributed communication environment

A decentralized management model enables a plurality of interconnected modules to be managed and controlled as an integrated unit without requiring any one of the interconnected modules to operate as a fully centralized manager. One of the interconnected modules is configured to operate as a base module, which coordinates certain network management operations among the interconnected modules. Each of the interconnected modules is capable of sending and receiving management and control information. Each of the interconnected modules maintains a segmented management database containing network management parameters that are specific to the particular module, and also maintains a shadowed management database containing network management parameters that are common to all of the interconnected modules in the stack. Management and control operations that do not require synchronization or mutual exclusion among the various interconnected modules are typically handled by the module that receives a management/control request. Management and control operations that require synchronization or mutual exclusion among the various interconnected modules are handled by the base module.

Decentralized management architecture for a modular communication system

A novel optical path switching system, architecture and technique wherein light beam data traffic is to be switched by MEMS mirrors between source and destination nodes, and test ports are used to set up optical paths even before the real data traffic is propagated, with a combination of an electrical mirror-sensing feedback loop for controlling coarse mirror positioning, and an optical path power-sensing feedback loop for controlling fine adjustments in the mirror position.

Method of and architecture for optically switching light communication signals in fiber optic networks and the like

A distributed address database management technique involves maintaining an address database by each of a number of interconnected modules. Each module maintains a number of locally owned address entries and a number of remotely owned address entries in the address database. Each module monitors the status of its locally owned address entries, maintains the locally owned address entries based upon the status, and provides the status to the other interconnected modules. Each module maintains the remotely owned address entries based upon the status received from the other interconnected modules. When a module adds a locally owned address entry to its address database, the module notifies the other interconnected modules, which in turn add a corresponding remotely owned address entry to their respective address databases. When a module purges a locally owned address entry from its address database, the module notifies the other interconnected modules, which in turn purge the corresponding remotely owned address entries from their respective address databases. Each module may periodically send a keep-alive message including a list of active addresses to the other interconnected modules, which maintain a persistence timer for each of the remotely owned address entries and purge a particular remotely owned address entry if the corresponding persistence timer expires before receiving a keep-alive message identifying the remotely owned address entry as an active remotely owned address entry. Upon receiving a keep-alive message, a module adds a remotely owned address entry for a particular address to its address database if such a remotely owned address entry is not already maintained in the address database. A module purges all remotely owned address entries from its address database if the module is reconfigured to operate in a stand-alone mode. A module purges all remotely owned address entries associated with a particular interconnected module if that particular interconnected module is removed.

System, device, and method for address management in a distributed communication environment

An enhanced spanning tree protocol for data communications networks having a multi-link trunk. In one embodiment, configuration messages are transmitted from boxes of the data communications network. In one embodiment, the configuration messages that are transmitted through all physical links of the same logical link, or multi-link trunk, include the same port Identifier. A network device that receives the configuration messages is therefore able to identify all of the physical links of a logical link. The enhanced spanning tree protocol according to one embodiment of the present invention considers all of the physical links of a multi-link trunk as a single logical link when identifying and removing loops in the data communications network to form a spanning tree.

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Lexington, MA, United States of America

Da-Hai Ding