Abstract: A node within a network comprising a transport layer protocol for multicasting datagrams on a virtual ring. Each node on the virtual ring is logically connected to two neighbour nodes through virtual connections. A virtual ring datagram is sent to a downstream neighbour node on the virtual ring and a token is received. The virtual ring is identified and the token is forwarded to the downstream neighbour node. If the received datagram is a virtual ring datagram, the virtual ring is identified and the node originator of the received virtual ring datagram is checked. If the received virtual ring datagram has not been locally originated, data in the virtual ring datagram is processed and the virtual ring datagram is forwarded to the downstream neighbour node on the virtual ring. If the received virtual ring datagram has been locally originated, the virtual ring datagram is removed from the virtual ring.

Abstract: A node within a network comprising a transport layer protocol for multicasting datagrams on a virtual ring. Each node on the virtual ring is logically connected to two neighbour nodes through virtual connections. A virtual ring datagram is sent to a downstream neighbour node on the virtual ring and a token is received. The virtual ring is identified and the token is forwarded to the downstream neighbour node. If the received datagram is a virtual ring datagram, the virtual ring is identified and the node originator of the received virtual ring datagram is checked. If the received virtual ring datagram has not been locally originated, data in the virtual ring datagram is processed and the virtual ring datagram is forwarded to the downstream neighbour node on the virtual ring. If the received virtual ring datagram has been locally originated, the virtual ring datagram is removed from the virtual ring.

Abstract: A method of bandwidth management enabling to insure a guaranteed bandwidth to each station of transmission network comprising a plurality of stations (10, 12, 14) forming a logical ring wherein a token frame is circulating from station to station, each station being allowed to transmit a credit (c) of data bytes upon reception of the token frame wherein the credit is increased in proportion to a variable TRTT standing for Token Round Trip Time which is the time taken for the token frame to circulate around the logical ring since the preceding reception of the token frame by the station. The credit is increased in proportion of a variable CIR standing for Committed Information Rate which is the guaranteed transmission rate that the station can use to transmit data wherein the value of CIR is determined by a class of bandwidth which has been previously selected by the station upon the preceding reception of the token frame by the station.

Abstract: A method of bandwidth management for ensuring a guaranteed bandwidth to each station of a transmission network (18) comprising a plurality of stations (10, 12, 14, 16), forming a logical ring wherein one of the stations is the ring manager and wherein a token frame is circulating along the logical ring from station to station, each station being allowed to transmit data to other stations over the transmission network when it receives the token frame while holding the token during the time the station is transmitting data. A credit of data bytes allowed to be transmitted is allocated to each station upon reception of the token frame when an Utilization Rate based upon the number of data bytes sent by all stations since the preceding reception of the token frame is greater than a predetermined threshold.

Abstract: A method of bandwidth management over a transmission network comprising a plurality of stations forming a logical ring that circulates a token from station to station. Each station is allowed to transmit data to other stations over the transmission network when it receives the token. The station is allowed to transmit C bytes, where C is a credit. The credit increases in proportion to the time spent since the preceding reception of the token by the station.

Abstract: A collision-free protocol for transmitting frames between stations connected over a shared transmission medium such as an IEEE 802.3 Ethernet LAN. A logical ring is formed and a token is circulated among the connected stations part of the logical ring (not all connected stations are required to be part of the logical ring). Transmitting from any one station, part of the logical ring, is permitted only while holding the token, therefore preventing collisions. A collision-free protocol, over a standard Ethernet infrastructure, becomes feasible, yet remains compatible with the standard collision protocol, thus improving performances.

Abstract: Method of establishing a route redundancy in a data transmission system using static routes, this system comprising a plurality of networks and a plurality of routers, a defined router (70) being able to use several routes to reach a destination network (72). This method comprises the steps of defining all the static routes toward the destination network, verifying for each defined static route whether the destination network is reachable resulting in a set of static routes considered as eligible to be used, defining a priority for each route of the set of static routes, and selecting the static route having the highest priority as the route to be used. A conventional static route may be used if none of these static routes is available.

Abstract: A method of bandwidth management for ensuring a guaranteed bandwidth to each station of a transmission network (18) comprising a plurality of stations (10, 12, 14, 16), forming a logical ring wherein one of the stations is the ring manager and wherein a token frame is circulating along the logical ring from station to station, each station being allowed to transmit data to other stations over the transmission network when it receives the token frame while holding the token during the time the station is transmitting data.

Abstract: A method of bandwidth management enabling to insure a guaranteed bandwidth to each station of transmission network comprising a plurality of stations (10, 12, 14) forming a logical ring wherein a token frame is circulating from station to station, each station being allowed to transmit a credit (c) of data bytes upon reception of the token frame wherein the credit is increased in proportion to a variable TRTT standing for Token Round Trip Time which is the time taken for the token frame to circulate around the logical ring since the preceding reception of the token frame by the station. The credit is increased in proportion of a variable CIR standing for Committed Information Rate which is the guaranteed transmission rate that the station can use to transmit data wherein the value of CIR is determined by a class of bandwidth which has been previously selected by the station upon the preceding reception of the token frame by the station.

Abstract: A method of bandwidth management over a transmission network comprising a plurality of stations forming a logical ring that circulates a token from station to station. Each station is allowed to transmit data to other stations over the transmission network when it receives the token. The station is allowed to transmit C bytes, where C is a credit. The credit increases in proportion to the time spent since the preceding reception of the token by the station.

Abstract: A collision-free protocol for transmitting frames between stations connected over a shared transmission medium such as an IEEE 802.3 Ethernet LAN. A logical ring is formed and a token is circulated among the connected stations part of the logical ring (not all connected stations are required to be part of the logical ring). Transmitting from any one station, part of the logical ring, is permitted only while holding the token, therefore preventing collisions. A collision-free protocol, over a standard Ethernet infrastructure, becomes feasible, yet remains compatible with the standard collision protocol, thus improving performances.

Abstract: An adapter for transferring blocks of data of a variable size to at least one destination adapter, each of the adapters being plugged in a respective slot and connected to a main system bus which is controlled by a central backplane card. In each adapter, the transmission of one block of data is provided, in part, by a device, operative in response to the detection of an ACK acknowledge word giving access to the bus, for generating a signalling word to be transmitted to a particular destination adapter which will actually receive the transmitted data; the signalling word comprising information characterizing the type of command which the transmitting adapter sends as a request to the backplane card, the address of the particular adapter which will receive the transmitted data, the size of the block of the transmitted data and the address of the transmitting adapter. The adapter is best suited for use in multimedia systems where variable size data blocks are required to transmit data, voice, video, etc.

Abstract: A conversion cache circuit, interfacing RISC busses to CISC peripheral circuits, provides master/slave Write and Read operations in a shared memory (130) and in the internal registers of the processor of said peripheral circuits (210). It enables RISC processor to Write and Read in the internal registers of the 8-bit processor in a salve operation while the 32-bit processor may perform the Write or Read operations to the shared memory through the conversion cache circuit in a master mode. The 32-bit processor may have access directly to the memory through its own direct access memory mechanism.

Abstract: A method for initializing ISDN adapter cards installed within a workstation having a main processor and an ISDN primary adapter for connecting the ISDN adapter cards to an ISDN primary gateway. Each ISDN adapter card has circuits for handling at least one B-channel, and a first processor associated with memory storage. The ISDN primary adapter includes a second processor associated with a second memory storage. In response to the reception of a specific polling pattern transmitted to each adapter card by the primary adapter, a pattern is transmitted to the workstation processor for requesting the loading of the second memory storage with operational code transferred from the workstation to the ISDN adapter card.

Abstract: Method for transmitting a unique high-rate digital data flow over n multiple different independent digital communication channels between two different primary terminal adapters. The method involves the steps of establishing, on request of a first DTE to a second remote DTE, a set of n independent digital communication channels between said terminal adapters and determining, during an initialization phase, the relationship between the slot of each channel used for the building of an aggregation superchannel and the chronologic order of the establishment of the considered slot. Then, the high-rate digital data flow is separated into bytes and each byte is transmitted through the independent digital channels in accordance with the chronologic order which was previously assigned to each of the said channels.

Abstract: An adapter having a line interface circuit for providing an analog attachment to a network (100). The line interface circuit is provided with a reset input for beginning a resynchronization of the timing of the adapter. The adapter further includes a Digital Phase-locked Loop device DPLL (203) driven by a master clock (306) which provides the timing and synchronization signals to the line interface circuits (201). The DPLL (203) divides a master clock down to an internal INT clock (309), a phase comparator (303) compares the INT clock with a reference signal (302) which is synchronized with the receive clock (202) extracted from the line by line interface (201). The phase comparison process operates with a Correction Signal (CS) which has a window centered around the falling edge of the INT clock. A frequency correction is initiated when the reference clock falls outside of the correction window and is achieved by inserting or suppressing a master clock pulse at this time.

Abstract: An apparatus for connecting a data communication equipment, such as a data terminating equipment (DTE) to an ISDN digital communication network providing a first 64 kbps and a second 64 kbps B digital communication channel which involve different transmission delays. The apparatus includes a transmit part with a separation for separating a unique high rate 128 kbps data flow into two distinctive 64 kbps data flows to be transmitted through both B channels. The apparatus includes a receive part (9999) including storage for storing the data received from digital network, measurement and comparison circuits for measuring the difference between the two transmission delays, address generators for addressing the storage in order to extract the data received through both digital channels, control circuits responsive to the measure and comparison for controlling the address generators in order to provide a 128 kbps which is not affected by the difference of transmission delays introduced by both digital channels.