International Business Machines Corporation

Cisco Technology, Inc.

Cisco Systems Inc.

Pierre-Andre Foriel

Claude R Galand

Aline Fichou

Jean-Marc Berthaud

Laurent Nicolas

Marcus Enger

Stephane Lengelle

Jean-Marie L Munier

Victor Spagnol

Francois Kermarec

This system is made to perform congestion detection and flow control in high speed digital packet switching network ( ) carrying discardable and non-discardable traffic. Forward traffic received at a destination system over a first connection from a source system is monitored. If a congestion-indicating bit is detected in a received packet, a backward congestion indicator is set in packets flowing from the destination system to the source system over a second connection. The source system integrates the number of backward congestion indicators received over successive periods of time using a count-up, count-down counter. Specific congestion control actions are taken at the source system as a function of the counter state at the end of each of the successive periods of time. The congestion control actions may include increasing or decreasing the bandwidth allocated to discardable traffic intended to be delivered over the first connection.

Method and system for implementing congestion detection and flow control in high speed digital network

A packet scheduling system for use in a switching node of a high speed packet switching network. Incoming packets are enqueued in connection queues. Each connection is classified as red (exceeding traffic profile) or green (within traffic profile). QOS priority is also identified for each connection. Packets are dequeued for transmission as a function of priority class and connection class. Higher priority class connections have priority over lower priority class connections. Within a given priority class of connections, green connections have priority over red connections. Round robin scheduling is used for packets from connections in the same priority and connection class. In addition, a dynamic priority coupling mechanism is provided to prevent red higher priority traffic from blocking green lower priority traffic.

Multiple-criteria queueing and transmission scheduling system for multimedia networks

Adaptive bandwidth allocation for Non-Reserved traffic over high speed transmission links of a digital network is operated through regulation of data packet transfers over network nodes/ports including input/output adapters connected through a switching device. A network node is assigned with a Control Point computing devise (CP) storing a Topology Data Base containing an image of the network. This Data Base is periodically and at call set up updated by Topology Data Base Update messages (TDUs) including an Explicit Rate parameter for link l indicating the current available bandwidth on link l, and a parameter NNRl indicating the number of Non-Reserved connections on link l. This information are used within each Adapter to periodically regulate the transmission bandwidth assigned to each Non-Reserved traffic connection within the network. To that end, each adapter is provided with an Access Control Function device for each attached connection (data source) and a Connection Agent (CA) getting, on request, required current link informations from the attached Topology Data Base.

Adaptive bandwidth allocation method for non-reserved traffic in a

In high speed cell switching networks, a Call Admission Control (CAC) procedure is performed on each connection according to a specified Traffic Descriptor. A mandatory parameter of the Traffic Descriptor is the Peak Cell Rate (PCR), associated with a Cell Delay Variation Tolerance (CDVT). Connections which specify a high CDVT value may potentially send into the network bursts of cells at a rate much higher than the declared Peak Cell Rate, which may lead to congestion in cell buffers of intermediate network nodes. Guaranteeing the Quality of Service (QoS) for such connections may require the reservation of a high amount of resources in the network, leading to poor utilization of those resources. A Call Admission Control procedure, associated with an Usage Parameter Control/Network Parameter Control mechanism, provides:

Flow control for very bursty connections in high speed cell switching

A system adapts access to a packet switching network. A dynamic bandwidth adaptation continuously monitors the mean bit rate of a signal source and the loss probability of a connection in the network. A filtering means removes noise from the mean bit rate and loss probabilty. A test means determine whether the values fall within a pre-defined acceptable adaptation region in a mean bit rate, loss probability plane. Triggering means initiate bandwidth adaptation procedures when the values fall outside of the region which in turn, initiate means for acquiring a new connection bandwidth, and determining new parameters for the adaptation mechanism.

Dynamic bandwidth estimation and adaptation in high speed packet

Method and system for adapting access to a packet switching network including a dynamic bandwidth adjustment mechanism which continuously monitors the mean bit rate of the signal source and the loss probability of the connection. These values are filtered to remove noise and then used to test whether the values fall within a pre-defined acceptable adaptation region in the mean bit rate, loss probability plane. Values falling outside of this region trigger bandwidth adaptation procedures which, in turn, result in acquiring a new connection bandwidth, and determining new parameters for the adaptation mechanism. Furthermore, the mechanism controls the number of connections that can be adapted by a single processor, given its processing capability. It ensures fairness between the connections in the sense that it prevents a single connection from using, on the average, a greater portion of the processor capacity than it should.

A method and an apparatus implementing a shaping function in a fixed length cell switching network node adapter supporting output lines in a telecommunication network. The adapter includes a Time Division Multiplexing (TDM) table where each entry is a pointer to a first cell of a queue of cells stored in the adapter for a given traffic. When a new traffic is established, the TDM table is updated. A placement device performs the pre-computation of the best placement of the entries reserved for one traffic in the TDM table. The placement device minimizes the Cell Delay Variation as computed by a Generic Cell Rate Algorithm (GCRA--ITU standard organization) policer. The Cell Delay Variation (CDV) is defined as the deviation of the placement of the cells from their ideal position in an output stream, the ideal placement being when the cells are spaced with an interval corresponding to the period of traffic negotiated at traffic establishment time. The preferred embodiment includes a scheduler which reads the TDM table and fetches the corresponding cell in the queue storage to send the cell onto the output line via a line interface unit.

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Pierre-Andre Foriel