Nortel Networks Corporation

Northern Telecom Limited

Rockstar Consortium US LP

Rockstar Bidco, LP

Rpx Clearinghouse LLC

Bell-northern Research Ltd.

Richard Vickers

Maged E Beshai

John Gerald Gruber

Asghar Ebrahim Methiwalla

Ernst A Munter

In a communication network comprising nodes and links between the nodes, a controller node disseminates link state information. A nodal routing table exists at each node comprising routes between pairs of nodes. The nodal routing table is either populated by the given node based on network information received from the controlling node or populated at the controlling node and received by the given node. Each node receives heartbeat signals from its neighbouring nodes. An unexpected delay between heartbeat signals may be perceived as a failure of a link. The perceived failure of that link is reported by the perceiving node to the controlling node. Upon receiving link failure information from a node, the controlling node may determine a subset of nodes in the network influenced by the link failure and indicate the link failure to the determined subset of influenced nodes.

State information and routing table updates in large scale data networks

In a communication network comprising nodes and links between the nodes, a controller node disseminates link state information. A nodal routing table exists at each node comprising routes between pairs of nodes. The nodal routing table is either populated by the given node based on network information received from the controlling node or populated at the controlling node and received by the given node. Each node receives heartbeat signals from its neighboring nodes. An unexpected delay between heartbeat signals may be perceived as a failure of a link. The perceived failure of that link is reported by the perceiving node to the controlling node. Upon receiving link failure information from a node, the controlling node may determine a subset of nodes in the network influenced by the link failure and indicate the link failure to the determined subset of influenced nodes.

A multi-grained network includes edge modules that switch high-variance multi-rate data traffic, and independent core modules that switch paths having different granularities. The core may include core modules that switch fixed-size data blocks, core modules that switch channels or bands of channels, core modules that switch entire links, and core modules that cross-connect channels or links. To simplify the control functions, the core modules operate independently from each other. Direct link, band or channel connections may be established for selected ingress-egress edge module pairs, if traffic volumes warrant. The use of graded granularity in the core simplifies the control function and reduces network cost.

Multi-grained network

Methods and apparatus for transferring data segments of a data stream across multi-channel links in a high-capacity network, so that the segments are equitably smeared across the channels of each multi-channel link, are described. The high-capacity network comprises a multiplicity of distributed high-capacity edge nodes interconnected by multi-channel links to a plurality of core nodes. Each edge node comprises a source node and a sink node which may share memory and control. A path from a source node of a first edge node to a sink node of a second edge node traverses two links, a first link from the source node to a selected core node and a second link from the selected core node to the destination sink node. Tandem switching through an intermediate edge node is not required, even for data streams of very low bit rate. Two types of core nodes are described. A core node of a first type is constructed as a high-capacity single-plane switch. A core node of a second type is constructed as a very-high capacity multiple-plane switch. Accordingly, traffic-load balancing across each multi-channel link in the network is realized by a data smearing process that is tailored to the core node type. A first-order data smearing method that balances the traffic loads among the channels of a first multi-channel link in a two-link path is used in conjunction with said first-type core nodes. A second-order data smearing method that balances the traffic load of each data stream across the channels of both links in a two-link path is used in conjunction with said second-type core nodes. Both first-order and second-order smearing methods are exercised at each source node, and the core nodes, regardless of their type, perform rudimentary tasks and are deliberately kept devoid of quality-control capability.

Multi-channel sharing in a high-capacity network

At a master controller of a space switch in a node in a data network, a request is received from a source node that requests a connection to be established through the space switch. This request is compared to other such requests so that a schedule may be established for access to the space switch. The schedule is then sent to the source nodes as well as to a slave controller of the space switch. The source nodes send data bursts which are received at the space switch during a short guard time between successive reconfigurations of the space switch. Data bursts are received at the space switch at a precisely determined instant of time that ensures that the space switch has already reconfigured to provide requested paths for the individual bursts. The scheduling is pipelined and performed in a manner that attempts to reduce mismatch intervals of the occupancy states of input and output ports of the space switch. The method thus allows efficient utilization of the data network resources while ensuring virtually no data loss.

Burst switching in a high capacity network

In a communication network comprising nodes and links between the nodes, a controller node disseminates link state information. A nodal routing table exists at each node comprising routes between pairs of nodes. The nodal routing table is either populated by the given node based on network information received from the controlling node or populated at the controlling node and received by given node. Each node receives heartbeat signals from its neighbouring nodes. An unexpected delay between hearbeat signals may be perceived as a failure of a link. The preceived failure of that link is reported by the perceiving node to the controlling node. Upon receiving link failure information from a node, the controlling node may determine a subset of nodes in the network influenced by the link failure and indicate the link failure to the determined subset of influenced nodes.

A self-configuring distributed switch is disclosed. The switch comprises a channel switch core connected by a plurality of channels to a plurality of high-capacity data switch modules. A global controller selects paths through the channel switch core and reconfigures the paths in response to dynamic changes in data traffic loads. Propagation delays between the data switch modules and the channel switch core are coordinated to keep reconfiguration guard time minimized. The advantage is a very high-capacity, load-adaptive, self-configuring switch that can be geographically distributed to serve a large geographical area.

Self-configuring distributed switch

A telecommunications network such as an ATM, Frame Relay or packet based network will be better managed by identifying nodes through which a virtual connection is routed between two end nodes. A new method of tracing the nodes on the route includes sending trace cells downstream of a monitoring node toward one or both end nodes. Each downstream node either loops back a trace cell identifying itself to the monitoring node or forwards the trace cell further. A plurality of trace cells sent along the route identify nodes located thereon. In one embodiment, the trace cell is an extension of the ATM FMOAM cell (ATM Fault Management OAM cell) specified for loopback functions.

Method of tracing the root of virtual connections

A self-configuring distributed switch has agile core modules connected by a plurality of channels to a plurality of large capacity edge modules. A core module controller selects paths through an associated core module and reconfigures the paths in response to dynamic changes in data traffic loads. Switching latency in the core modules is masked so that the source edge modules need not disrupt data transmission during reconfiguration. Surplus capacity is provided in the core modules to facilitate reconfiguration. Connection release and connection setup policies increase occupancy variance among the space switches in each core module to further facilitate reconfiguration. The reconfiguration functions of the data switch modules and the core modules are coordinated to keep reconfiguration guard time minimized. The advantage is a high capacity, load-adaptive, self-configuring switch that can be geographically distributed to serve a large geographical area.

Agile optical-core distributed packet switch

Methods and apparatus for control of a multi-class digital network are described. The network supports a plurality of digital services using dynamically-configured service bands to support various transport modes and qualities of service. Flexible controls with two degrees of freedom are used at the node level to dynamically configure the transport bands. The first degree of freedom is realized using adaptive alternate routing to balance the traffic intensity across the network and, hence, increase the efficiency of the band. The second degree of freedom is achieved through adaptive network partitioning to provide elasticity to the band structure. This permits band capacity to be adaptively reconfigured as connections are added and dropped. The switching nodes use rate controllers to divide the capacity of each link among the connection classes according to rules which ensure consistent service attributes for each band across the network. The rate controllers are adapted to support different transport modes and different packet sizes so that the deconstruction and reconstruction of packets at network edge devices is eliminated. The advantage is a flexible multi-class network which dynamically reconfigures to service traffic loads as service demands fluctuate.

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Kanata, Canada

Richard Vickers