Alcatel Canada Inc.

Alcatel Lucent

Alcatel

Alcatel-lucent Canada Inc.

Alcatel Networks Corporation

Tom Edward Davis

Natalie Giroux

Predrag Kostic

Charles Mitchell

Chad William Kendall

Hossain Pezeshki-Esfahani

Jason T Sterne

Robert Elliott Robotham

Peter Irma August Barri

Bart Joseph Gerard Pauwels

Denny L Lee

Denny L S Lee

Sudhakar Ganti

Olivier Didier Duroyon

Shay Nahum

Marie-Claude Bonneau

Charlie Sabry

Anthony Hung

Robert Nesbitt

Esmond Ho

Kostic Predrag

Ganti Sudhakar

The invention relates to a telecommunication network having IP packet-supporting capabilities, which includes a load distribution processing function, either centralized or distributed, by means of which a load distribution function may be applied to sets of paths between network nodes or sets of links of network trunks. The load distribution processing function handles different load distribution functions. Each of the different load distribution functions is associated to a different network input unit involved in the load distribution for a set of paths between network nodes or a set of trunk links. The invention also relates to a method of load distribution in a telecommunication network as summarized above.

Method for distributing load over multiple shared resources in a communication network and network applying such a method

Techniques for bandwidth management and flow control on a resilient packet ring (RPR) network is described. The RPR requires allocation and guarantee of a bandwidth for each channel between two nodes on the ring. The bandwidth is managed by shaping traffic on a channel at the source by using a bandwidth allocation factor calculated at each node. The bandwidth allocation factor, which is communicated to other nodes, is calculated by using a recursive nonlinear function of the transit buffer size.

Bandwidth management of resilient packet ring network

The backpressure flow control mechanism is widely used in telecommunications network. Actions of the flow control scheme are not instantaneous in that latency always exists between action and reaction, resulting in a flow control round trip time. This flow control round trip time causes ambiguity in determining the amount of traffic in transit. The invention monitors the amount of traffic which is on the way toward the queue during the past period of the round trip time, thus eliminating the ambiguity. A more precise control of traffic flow is possible, realizing reduction of storage space in the queue by one half. In one embodiment, the invention keeps a historical record of flow control signals sent back during the most recent flow control round trip time.

Backpressure history mechanism in flow control

A packet processing device has an on-board match engine memory. Actions to be taken on a packet can be looked up in the match engine memory using a key comprising a match engine index and a protocol field from the packet. The match engine index is obtained from either a relatively small on-board parser memory or a larger context memory. The parser memory contains match engine indices for sparse protocols. Performance approaching that of hard-wired packet processors can be obtained. New protocols or changes in protocols can be accommodated by writing new values into the match engine, parser and context memories. The packet processing device can be provided in a pipelined architecture.

Configurable packet processor

A policing technique for a telecommunications traffic of variable length packets is described. The technique uses a plurality of police engines, grouped in pairs. A selection module selects a police engine pair to process a packet. Each police engine contains a conformance unit, credit unit and a debit unit, in which the credit update of one police engine influences the credit update of the other police engine in the pair. The technique also uses a combinatorial function to decide on a category of a processed packet and which police engines to update their debit units.

Flexible policing technique for telecommunications traffic

A system and method for adaptively assigning queue service weights to an ATM traffic management controller in order to reduce service weight update calculations. The implementation of a fair weighted queuing scheme on a network is divided into two functions: queue arbitration; and queue weight configuration. Queue arbitration is performed via a virtual time-stamped fair queuing algorithm. The queue weight configuration is performed via a reconfigurable weighted fair queuing controller wherein bandwidth requirements are calculated in response to connection setup and release values.

Adaptive service weight assignments for ATM scheduling

A system and method for managing high speed traffic though switching elements in a digital network such as an asynchronous transfer mode (ATM) network. The system applies in particular to available bit rate (ABR) and unspecified bit rate (UBR) categories of service in an ATM network. ABR traffic incorporates resource management cells (RM) in a feed back loop from destination to source for the purpose of carrying explicit rate (ER) congestion control information. Lookup tables are provided in order to quickly provide ER information to the RM cells. UBR traffic is subject to cell discard in the event of congestion. Lookup tables are provided in order to fairly apply an early packet discard (EPD) algorithm.

High speed traffic management control using lookup tables

The method and system for buffering packets such as ATM cells at a queueing point of a device which employs a connection-orientated communications protocol includes the steps of logically partitioning a memory into plural reserved buffer spaces allocated to traffic classes and a shared buffer space available to any connection; determining whether to store or discard a given packet based on predetermined discard criteria; and filling the reserved buffer space to a predetermined state of congestion before storing the given packet in the shared buffer space. Reserved buffer space congestion states are defined with respect to individual connections, groups of connections, and the total capacity of the reserved buffer space itself. Packets are discarded when any, or alternatively a specific combination, of corresponding congestion states occur, and the shared space is congested as well. The system facilitates the balance between the sharing of physical memory resources amongst distinct and various types of traffic flows and the logical isolation thereof.

Flexible threshold based buffering system for use in digital communication devices

The method of buffering packets in a digital communications device includes defining an n-level hierarchy of memory partitions, wherein each non-top level partition has one or more child partitions at an immediately lower level of the hierarchy. The memory partitions at the top-most level are pre-configured with a target memory occupancy size, and the target occupancy for each memory partition situated at a lower level is recursively computed in a dynamic manner based on the aggregate congestion of its parent partition, until the target occupancies for the bottom-most memory partitions are determined. Each traffic flow which uses the buffer is associated with one of the memory partitions at the bottom-most level of the hierarchy and packet discard is enabled in the event the actual memory occupancy of a traffic flow exceeds its target occupancy. The memory partitions at higher levels are preferably associated with a group or pool of traffic flows, such as traffic flows associated with a particular egress port and class of service, to thereby selectively control aggregate congestion. The method allows full buffer sharing, the weighted distribution of memory space within a memory partition, and scales easily to large systems.

Buffering system employing per traffic flow accounting congestion control

In an N&times;N packet switch, for example an ATM switch, multicast connections receive backpressure signals from congested output ports in the switch core. The cells in the connections are destination address modified not to send to the congested output port, but to continue sending to the other output ports in the connection. The multicast cells may include a user selected primary route identification and be queued in a unicast input queue for the primary route before being destination address modified. Destination address modification for congestion may be accompanied by partial packet discard, through destination address modification of the remaining cells forming part of a multiple cell packet to remove the destination address for the congested port (whether or not it is now congested) where one of the multiple destination addresses of one of the cells in the packet has been modified to remove the destination address of the congested output port. Destination address modification for congestion, without or without partial packet discard, may be accompanied by hybrid head of line blocking performed by not sending from a multicast queue if an output port on one of the multicast leafs is congested and the input queue size is below a given threshold, and sending with destination address modification and optional partial packet discard if the queue size is above the threshold.

Multicast methodology and apparatus for backpressure-based switching fabric

A device and algorithm for fairly allocating available bandwidth between contending connections at a contention point in a data network. The allocation is based on global queue size at the contention point and a weighted value assigned to the data traffic. The device and algorithm find particular application in an ATM network which supports the available bit rate (ABR) service category.

Fair share bandwidth allocation algorithm and device

A scheduling device for use in a packet-switched network, belonging to the class of non-work conserving or idling weighted round robin (WRR) arbiters, assigns a packet stream slots in a fixed-length time division multiple access (TDMA) frame by selecting free slots which are closest to ideal slot positions that would, if assigned, eliminate jitter or cell delay variation. The scheduler is able to simultaneously determine if a new constant bit rate connection requiring a predetermined bandwidth conforms to a leaky bucket or GCRA algorithm characterized by a peak packet or cell emission interval T&equals;1/PCR and a packet or cell delay variation time, CDVT, i.e., whether the new connection is GCRA (T, CDVT) conformant. This determination is made by comparing the quantity ME&plus;ML against the CDVT, where ME corresponds to the maximum time or distance by which any assigned slot is earlier than a corresponding ideal slot and ML corresponds to a maximum time or distance by which any assigned slot is later than a corresponding ideal slot. The scheduler can thus also carry out connection admission control (CAC) functions in an ATM network switch.

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Tom Edward Davis