Abstract: The present invention relates to a transmission device implementing a flow control mechanism for aggregate trunks. The transmission device can be implemented as a router that includes an input for receiving aggregate traffic streams, an output for releasing the aggregate traffic streams to a destination point and a control unit capable to regulate the rate of release of packets from the output. Specifically, the flow control operation effected by the control unit is dependent on receipt of acknowledgement messages issued at the destination point, each acknowledgement message confirming the receipt of one or more particular packets at the destination point. The control unit will continuously increase the packet sending rate until a packet is lost in the network between the transmission device and the destination point. On detection of packet loss, based on the lack of one or more corresponding acknowledgement messages from the destination point, the control unit will reduce the packet sending rate.

Abstract: Transport networks are facing new challenges and opportunities because of the explosive growth of data traffic. Besides having to meet the ever increasing bandwidth demand, transport networks need to provide new functionalities for the support of data applications. Novel enhanced transport systems with inherent packet multiplexing to meet these challenges are described. It uses Internet protocols and technologies to implement these packet transport systems, and thereby re-use much of the existing Internet infrastructure already widely deployed.

Abstract: The present invention relates to a switch for processing data units, such as IP data packets. The switch can be implemented as a router that includes a plurality of input ports, a plurality of output ports and a switch fabric capable of establishing logical pathways to interconnect a certain input port with a certain output port. A characterizing element of the router is its ability to control bandwidth usage on a basis of a logical pathway. This prevents congestion to occur in the switch fabric and also at the level of the output ports. For every active logical pathway the router sets-up a bandwidth control mechanism including at least one queue to hold data units received at an input port. The bandwidth control mechanism performs an accounting operation to determine the average bandwidth usage and if less than a threshold requests for releasing data units in the switch fabric are sent to the switch fabric controller.

Abstract: The present invention relates to a switch for processing data units, such as IF data packets. The switch can be implemented as a router that includes a plurality of input ports, a plurality of output ports and a switch fabric capable of establishing logical pathways to interconnect a certain input port with a certain output port. A characterizing element of the router is its ability to control bandwidth usage on a basis of a logical pathway. This prevents congestion to occur in the switch fabric and also at the level of the output ports. For every active logical pathway the router sets-up a bandwidth control mechanism including at least one queue to hold data units received at an input port. The bandwidth control mechanism performs an accounting operation to determine the average bandwidth usage and if less than a threshold requests for releasing data units in the switch fabric are sent to the switch fabric controller.

Abstract: Flow control of packet based traffic by window is known. Novel modification is described which causes the flow control mechanism to reduce sending rate to some configured number rather than just reducing it by a fixed amount such as one half. The description also shows how the flow control mechanism can be constrained to a maximum rate. The configured numbers will assure that the connection can always run at a minimum rate but not more than a maximum rate. If the guaranteed minimum bandwidth is known and the round trip time between the end points is known or has been calculated, then the sender node needs only reduce its window to that which corresponds to a sending rate equal to that configured number. In this way the protocol will still probe for extra, opportunistic bandwidth but will be able to maintain the minimum rate. In a similar way a window that corresponds to the maximum rate can be calculated and used to constrain the maximum rate of sending.

Abstract: A method of monitoring telecommunications network traffic comprising the steps of: receiving a packet stream comprising packets each identified as belonging to one of at least three classes; calculating a difference between the numbers of packets received identified as belonging to a first and a second of said classes; and deriving a measure of traffic load on the network responsive to said difference. The invention also relates to a method for admission control based on the above method of monitoring and a method for overcoming admission control avoidance. It also relates to apparatus embodying these methods.

Abstract: Congestion at a network node can be aggravated by having too many TCP connections. A simple method of avoiding the bad effects of too many TCP connections is to limit the number of connections. Limiting the number of connections is achieved by an admission control which delays or even discards the connection set-up packets. TCP traffic flows are monitored to generate packet loss characteristics and when a certain condition is met, a connection request queue is disabled.

Abstract: Transport networks are facing new challenges and opportunities because of the explosive growth of data traffic. Besides having to meet the ever increasing bandwidth demand, transport networks need to provide new functionalities for the support of data applications. Novel enhanced transport systems with inherent packet multiplexing to meet these challenges are described. It uses Internet protocols and technologies to implement these packet transport systems, and thereby re-use much of the existing Internet infrastructure already widely deployed.

Abstract: The present invention relates to a lossy switch for processing data units, for example IP data packets. The switch can be implemented as a contained network that includes a plurality of input ports, a plurality of output ports and a lossy switch fabric capable of establishing logical pathways to interconnect a certain input port with a certain output port. A characterizing element of the switch is its ability to control the discard of data packets at a transport point within the switch. This control mechanism prevents and reduces congestion which may occur within the switch fabric and at the level of the input and output ports. The system also supports priorities, routing HI priority request data packets over the switch fabric before LO priority request data packets, and discarding LO priority data packets first when controlling congestion.

Abstract: The invention provides a method and apparatus for re-ordering data traffic units, such as IP data packets, that may have been miss-ordered during a transmission over a multi-pathway link between a source node and a destination node in a network. The re-ordering apparatus includes a storage medium for intercepting the IP data packets and holding the IP data packets to allow IP data packets delayed on slower pathways to catch-up. The IP data packets in the storage medium are re-ordered based on their sequence number in an attempt to restore the original order of the IP data packets. A maximal time delay variable determines how long a certain IP data packet can be held in the storage medium. The TP data packet is released prior to the maximal time delay variable or as the maximal time delay variable is exceeded.

Abstract: The present invention relates to the field of data communication networks. More specifically, it pertains to devices and methods for the management of bandwidth on links between routing nodes in data networks. The system is particularly useful for reducing congestion caused by high volume traffic streams. The invention provides a novel router that separates traffic on the basis of data type into separate queues buffers. The various queue buffers are associated with virtual output ports on a common physical link. A scheduler regulates the data release from the queue buffers into the physical link to control the bandwidth portion that is made available to each type of data.

Abstract: Multi-media networks will require that a data flow be given certain quality-of-service (QOS) for a network connection but pre-negotiation of this sort is foreign to the current data networking model. The real time traffic flow in the data network requires distinct limits on the tolerance to delay, and the variations in that delay. Interactive voice and video demand that the total delay does not exceed the threshold beyond which human interaction is unacceptably impaired. The present invention allows the network to discover the nature of the service for each traffic flow, classifies it dynamically, and exercises traffic conditioning by means of such techniques as admission control and scheduling when delivering the traffic downstream to support the service appropriately.

Abstract: Multi-media networks will require that a data flow be given certain quality-of-service (QOS) for a network connection but pre-negotiation of this sort is foreign to the current data networking model. The real time traffic flow in the data network requires distinct limits on the tolerance to delay, and the variations in that delay. Interactive voice and video demand that the total delay does not exceed the threshold beyond which human interaction is unacceptably impaired. The present invention allows the network to discover the nature of the service for each traffic flow, classifies it dynamically, and exercises traffic conditioning by means of such techniques as admission control and scheduling when delivering the traffic downstream to support the service appropriately.

Abstract: A plurality of end devices are coupled via a shared port to an asynchronous network in which traffic is carried in cells. A cell multiplexer is disposed between the devices and the port and is adapted to multiplex cells from the devices to the port in the order in which they are received by the multiplexer. The multiplexer broadcasts cells received from the network to all of the devices. Each said device is allocated a respective VCI so that it can identify its own cells from the broadcast cells.

Abstract: A TDM PCM communication system includes a plurality of user terminals, a switching network and a CPU for controlling the establishment of transmission paths between the user terminals and the switching network for the transfer of information between predetermined ones of the user terminals. An incoming path carries information bits from the user terminals to the switching network and an outgoing path carries information bits from the switching network to the user terminals. The switching network includes means for transferring single information bits each residing in a time slot period from the incoming path to the outgoing path. The transferring means includes an exchange means for effecting a bilateral exchange of information bits in fixed pairs of time slot periods, whereby paths for information bit transmission are periodically provided between ones of the user terminals, as determined by the CPU.

Abstract: A pair of interchangeable memories is provided, one of which receives a PCM frame while simultaneously transmitting one, while the other of which, containing the previous frame, outputs the channel bits for parallel processing. Each simultaneous conference is assigned a temporary storage location in which the associated channels are accumulated to yield the total conference signal. Subsequently, each channel is subtracted from its conference total to produce the final conference signal. The final conference signals replace the unprocessed frame in the memory where, at the end of the current frame, it is interchanged with the other memory. And so on.