Nortel Networks Corporation

Nxp B.v.

Nxp Usa, Inc.

Ciena Corporation

Rpx Clearinghouse LLC

Bernard Francois St-Denis

John Frank Pillar

Bernard Marchand

John F Pillar

Allen Lengacher

Peter J Ashwood-Smith

Marc Holness

Adi Katz

Paul Allen Bottorff

Bashar Abdullah

Dwight D Jamieson

Scott Larrigan

Ameel Kamboh

Feng Xian

John Pillar

Eric Englert

Sathish Vallipuram

Mark Andrew Schellhorn

A sequence recovery method is executed by a node in a time-sensitive network configured to transmit and receive packets The method includes providing a state variable, having a first state in which a packet loss counter is disabled, and a second state in which the packet loss counter is enabled. The packet loss counter can only be incremented to count lost packets when the loss state variable is in the second state. This method enhances the IEEE 802.1CB standard.

Counting packet loss in sequence recovery method

A network station scheduling a frame to be transmitted by a transmitter of the network station at a transmit time. The transmit time is based on a first clock. A request is then issued to a direct memory access (DMA) circuit to retrieve the frame from a system memory. An advance time offset associated with the first clock is determined based on an estimated DMA latency of the DMA circuit. A frame retrieved by the DMA circuit is provided to a staging circuit. When a time of a second clock reaches the transmit time of the frame in the staging circuit, the frame is transmitted at the transmit time. In an example, a time of the first clock is ahead of a time of the second clock by the advance time offset.

Frame scheduling based on an estimated direct memory access (DMA) latency and apparatus for time aware frame scheduling

Cut-through frame transfer or store-and-forward frame transfer of a frame in an network switch is disclosed. A frame is received from an input port of the switch. A time period in a cycle time when the frame is received and a stream identification of the frame is determined. One of the cut-through frame transfer and the store-and-forward frame transfer of the frame is performed based on the time period in the cycle time when the frame was received and the stream identification.

Disabling cut-through frame transfer based on a cycle time period and apparatus for disabling

A sequence recovery method executed by a node in a time-sensitive network, the method comprising receiving a packet having a sequence number, determining whether the sequence number is within a predetermined range of a reference sequence number, wherein the reference sequence number is a current latest sequence number accepted by the node, and wherein the predetermined range comprises a history range and a future range, wherein the history range has a length equal to a history length and includes the reference sequence number and a predetermined number of consecutive sequence numbers that are immediately earlier than the reference sequence number, and the future range has a length equal to a future length and defines a predetermined number of consecutive sequence numbers that are immediately later than the reference sequence number, wherein the future length is greater than the history length.

Extending acceptable sequence range

A mechanism is provided to maximize utilization of internal memory for packet queuing in network devices, while providing an effective use of both internal and external memory to achieve high performance, high buffering scalability, and minimizing power utilization. Embodiments initially store packet data received by the network device in queues supported by an internal memory. If internal memory utilization crosses a predetermined threshold, a background task performs memory reclamation by determining those queued packets that should be targeted for transfer to an external memory. Those selected queued packets are transferred to external memory and the internal memory is freed. Once the internal memory consumption drops below a threshold, the reclamation task stops.

Method and system for effective use of internal and external memory for packet buffering within a network device

Methods and systems are disclosed to access memory locations using auxiliary keys in addition to primary keys. Commands are received by a memory management unit to insert or access records in an exact match keyed lookup table where records include keys (i.e., primary keys), auxiliary keys, and data. When a command to insert a new record is received along with key and data, the memory management unit generates a new unique auxiliary key. The auxiliary key includes a table index generated from the key and a collision index that is unique for any records having the same table index. The key, the auxiliary key, and the data for the new record are then stored within the lookup table along with a collision pointer that links records having the same table index. Subsequently, commands to access the new record can selectively use either the original key or the auxiliary key.

Systems and methods to access memory locations in exact match keyed lookup tables using auxiliary keys

Interfaces may be created for applications on a network element without requiring the applications to include code specific for that type of interface. An Interface Management System (IMS) may be included to provide a media abstraction layer between applications and physical media to enable interfaces to be bound to applications without modifying the application to accommodate the interface and without modifying the interface to accommodate the application. The IMS also provides an environment to support distributed interface creation to enable interfaces to be created in a distributed fashion to avoid congestion in the IMS and to facilitate sparing of the IMS and interfaces. The interfaces communicate with applications and with each other through an IFID manager to streamline communications, and to enable the IMS to keep track of the interfaces that have been created on the network element.

Method and apparatus for managing interfaces on a network element

A system for controlling packet forwarding through a dual-homed connection between first and second network domains, the dual-homed connection including two peer nodes connected to the first and second network domains. A sub-ring network is instantiated in the first network domain, and includes at least two nodes connected in a linear topology between a pair of end-nodes. Each end-node corresponds with a respective one of the peer nodes. A virtual link through the second network domain for conveys traffic of the sub-ring network between the peer nodes, and closes the sub-ring network to define a ring topology. Each of the nodes of the sub-ring network is controlled to forward packets of the sub-ring network in accordance with a ring network routing scheme.

Dual homed E-spring protection for network domain interworking

In Asynchronous Transfer Mode (ATM) communications networks, certain congestion control features, such as Partial Packet Discard (PPD) and Early Packet Discard (EPD), operate on ATM cells that have been segmented from ATM Adaptation Layer #5 (AAL5) frames (packets). AAL5 frames are automatically detected by observing transitions of an indicator in the ATM cell header unique to AAL5 traffic. Automatic detection of AAL5 traffic allows enablement of packet-aware cell discarding techniques such as PPD and EPD on a Virtual Channel Connection (VCC) basis, whether in a switch for a VCC or for a Virtual Path Connection (VPC) to which the VCC belongs.

Method and apparatus for auto detection of AAL5 type frames for VCC and VPC switches

A data plane architecture enables IP applications, hosted on any processor within a network element, to define steering policies that may be implemented in the data plane. The steering policies enable the applications to define steering policies containing both attributes and actions. The attributes are used to identify the packets and the actions are used to define how the data plane of the network element should handle the packets. The steering policies are implemented in the data plane of the network element by a data path policy steering process. The data path policy steering process operates to implement steering policies defined by applications to cause IP termination to occur at any processor on the network element or optionally at a processor off the network element.

Application specified steering policy implementation

The invention provides a method and apparatus for policing a traffic flow in which a first stage of policing is performed on the traffic flow to produce a first stage conforming flow and a first stage violating flow. These two flows are then policed again in a second stage of policing, such that the first stage conforming flow can take advantage of a capacity allowed for the first stage violating flow which is unused by the first stage violating flow. In some embodiments, performing a first stage of policing involves associating each packet of the traffic flow with one of a plurality of sub-flows, policing at least one of the plurality of sub-flows individually to produce for each sub-flow a respective conforming sub-flow and a respective violating sub-flow. The conforming sub-flow(s) collectively are the first stage conforming flow. The violating sub-flows collectively are the first stage violating flow.

Multi-flow multi-level leaky bucket policer

User traffic of one type must traverse many diverse networks, each operating by different paradigms and requiring different protocol stacks, before it reaches the destination. MPLS (Multiprotocol Label Switching) is being developed to solve some of the problems which involve the existence of different protocols along the traffic path. There is currently no accepted way of transporting ATM cells over an MPLS domain. New ways of packetizing ATM cells into labeled MPLS packets for transporting over an MPLS domain are described.

ATM transport over multi-protocol label switching

In Asynchronous Transfer Mode (ATM) communications networks, certain congestion control features, such as Partial Packet Discard (PPD) and Early Packet Discard (EPD), operate on ATM cells that have been segmented from ATM Adaptation Layer &num;5 (AAL5) frames (packets). AAL5 frames are automatically detected by observing transitions of an indicator in the ATM cell header unique to AAL5 traffic. Automatic detection of AAL5 traffic allows enablement of packet-aware cell discarding techniques such as PPD and EPD on a Virtual Channel Connection (VCC) basis, whether in a switch for a VCC or for a Virtual Path Connection (VPC) to which the VCC belongs.

Inter-class schedulers for digital link systems provide high efficiency utilization of limited bandwidth by employing queuing techniques referred to as Statistical Priority Guarantee Queuing (SPGQ) and Generic Cell-Rate Algorithm Priority Guarantee Queuing (GCRA-PGQ). SPGQ &ldquo;elevates&rdquo; the priority of otherwise low-priority classes under prescribed circumstances in accordance with a statistical process. The SPGQ scheduler determines whether a number within a range produced by a uniform random number generator lies within a sub-range proportional to the programmed statistical guarantee for a given class. If the number lies within the sub-range associated with a given class, then the priority of that class is elevated to a higher priority when both are eligible to transmit. The GCRA-PGQ scheduler operates as a strict priority mechanism until a class requires bandwidth in excess of a GCRA &ldquo;window&rdquo; or threshold for that class. When that occurs, the service priority of that class is temporarily lowered.

Inter-class schedulers utilizing statistical priority guaranteed queuing and generic cell-rate algorithm priority guaranteed queuing

In Asynchronous Transfer Mode (ATM) communications networks, certain congestion control features, such as Partial Packet Discard (PPD) and Early Packet Discard (EPD), operate on ATM cells that have been segmented from ATM Adaptation Layer &num;5 (AAL5) frames (packets). AAL5 frames are automatically detected by observing transitions of an indicator in the ATM cell header unique to AAL5 traffic. Automatic detection of AAL5 traffic allows enablement of packet discard techniques such as PPD and EPD.

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Ottawa, Canada

Bernard Francois St-Denis