International Business Machines Corporation

Jean-Pierre Marce

Pascal Thubert

Denis Esteve

Lionel Denecheau

Jean A Lorrain

Rene Brassier

In a data communication network operated under the TCP/IP suite of protocols the invention adds an adaptive streaming (AS) layer, inserted between the IP and the TCP protocol layers, in which the received data packets of each open TCP connection are temporarily queued and from where they are first reordered then, delivered to the TCP layer at a pace matching the optimal receiving rate of TCP connections. Thus, the invention adds a rate-based transmission mechanism to the TCP layer for the received data packets so as to better adapt to higher-speed communication lines and to reduce drastically the burstiness of the TCP flow control.

System and method for providing an adaptive streaming flow control mechanism between the TCP and IP layers of the TCP/IP suite of protocols

A system, method and article of manufacturing for increasing link bandwidth occupation in a high speed packet switching digital network by enabling merging the traffics provided by different source users over several network node entry ports and to be propagated throughout network paths toward a same destination network port. To that end, at network ingress, the original packets provided by said source users and entering the network, are encapsulated with a so-called Single Sided Virtual Channel (SSVC) header including a Data Link Connection Identification (DLCI) field. Then, the packets provided by said source users and entering a given network node along their predefined path are monitored. Said packets SSVC headers DLCI fields are loaded with a same Virtual Channel number, whereby the corresponding traffics are being merged into a same channel, down to the destination network node. Then, the packets in said destination node are de-encapsulated from said SSVC header.

System, method, and article of manufacture for increasing link bandwidth utilization in a high speed digital network

A system and method for converting a window based data link flow control to a rate based flow control. In addition to the conventional data link control window, a second window is established under control of an adaptive committed information rate (ACIR). When either the DLC window or the second window is closed information frames are queued. The second window is closed when a frame exceeds the burst size authorized in the ACIR.

Method and apparatus for adapting window based data link to rate base link for high speed flow control

To assure a complete transmission of frames in communication protocol such as the X25 LAPB a timer is used. The integrity of the transmission is obtained by retransmitting Iframe that are not received. Thus, each frame that is sent is controlled by a timer, called Retry Timer or T1 Timer. A short T1 Timer may cause a de-synchronization of the protocol then a connection loss. The invention aims to avoid this problem. The principle is based on the fact that the T1 Timer value is defined not only according to the speed but also to the workload of the LINK (51). The invention aims to add automatically to the initial value of the T1 Timer a queue delay. This queue delay corresponds to the delay between the enqueue of a buffer pointer (11) and the transmission of this buffer (41) on the Link. Thus, T1 Timer becomes auto-adaptive. The invention consists in performing two actions. The first action is to measure dynamically the queue delay. For this purpose, a transmit scheduler (40) sets a marker (46) in a transmit queue (30). When the transmit scheduler dequeues this marker, it updates the Queue delay in a register (60) and re-enqueues the marker. The second action is to adapt dynamically the T1 Timer. After sending a frame, if the T1 Timer expires without reception of an acknowledgment, then T1 timer is started with another value corresponding the queue delay measured above. And if the timer expires again then the LAPB (10) starts a confirmation mechanism in order to retransmit the Iframe that is not received.

Method and apparatus for auto-adapting a retry timer to avoid

A method and apparatus for detecting the absence of an activity or event during a time period D divides the time period D into N equal time sub-periods. A register is reset upon the occurrence of an event or activity. The register is incremented at the end of each sub-period and examined to determine if it exceeds the value N in which case there has been no activity during the time period D. The precision of the measurement is regulated by increasing or decreasing the value of N and the sub-periods are determined by dividing D by N.

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St Jeannet, France

Jean-Pierre Marce