Abstract: There is provided a method and system for inserting a second node into a virtual ring, wherein the virtual ring comprises at least a first node, wherein the first node comprises a virtual ring manager for the virtual ring and wherein the first node is linked with a database.

Abstract: In a network having nodes, N nodes are members of a virtual communications ring for multicast communication among the N Nodes, each of the N Nodes being associated with only an upstream and a downstream one of the other N nodes. One of the N nodes manages changes in ring membership, including requesting the others of the N nodes to participate in measuring distances to a N+1th, node responsive to receiving an insertion request message. The manager node inserts the N+1th node in the communications ring responsive to receiving replies, which includes inserting the N+1th node in a selected location between two selected ones of the N Nodes, such that the N nodes and the N+1th node are enabled to multicast messages around the ring. Due to the selected location of the N+1th node, communication distances for multicasted messages tend to be shorter than such distances that would otherwise occur.

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 non-linear slide presentation management for slide show programs. In a first aspect, the invention provides a method for non-linear slide presentations, comprising: interrupting a topic sequence of a slide presentation being currently shown; placing a slide identifier from the interrupted topic sequence on a stack; showing a new topic sequence of the slide presentation; and upon completion of the new topic sequence of the slide presentation, returning to the interrupted topic sequence by examining the stack to obtain the slide identifier from the interrupted topic sequence.

Abstract: In a network having nodes, N nodes are members of a virtual communications ring for multicast communication among the N nodes, each of the N nodes being associated with only an upstream and a downstream one of the other N nodes. One of the N nodes manages changes in ring membership, including requesting the others of the N nodes to participate in measuring distances to a N+1th, node responsive to receiving an insertion request message. The manager node inserts the N+1th node in the communications ring responsive to receiving replies, which includes inserting the N+1th node in a selected location between two selected ones of the N nodes, such that the N nodes and the N+1th node are enabled to multicast messages around the ring. Due to the selected location of the N+1th node, communication distances for muticasted messages tend to be shorter than such distances that would otherwise occur.

Abstract: There is provided a method and system for inserting a second node into a virtual ring, wherein the virtual ring comprises at least a first node, wherein the first node comprises a virtual ring manager for the virtual ring and wherein the first node is linked with a database.

Abstract: The present invention is directed to a method, system and computer program as defined in independent claims, for optimizing the topology of a virtual ring used to multicast datagrams within a network comprising a transport layer protocol providing end to end data transfer, each node on the virtual ring being logically connected according to the network transport layer protocol to two and only two neighbour nodes through virtual connections, an upstream neighbour node and a downstream neighbour node.

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: In a network having nodes, N nodes are members of a virtual communications ring for multicast communication among the N nodes, each of the N nodes being associated with only an upstream and a downstream one of the other N nodes. One of the N nodes manages changes in ring membership, including requesting the others of the N nodes to participate in measuring distances to a N+1th, node responsive to receiving an insertion request message. The manager node inserts the N+1th node in the communications ring responsive to receiving replies, which includes inserting the N+1th node in a selected location between two selected ones of the N nodes, such that the N nodes and the N+1th node are enabled to multicast messages around the ring. Due to the selected location of the N+1th node, communication distances for muticasted messages tend to be shorter than such distances that would otherwise occur.

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: A method of updating an inverse ARP table in an IP network over a partially meshed Frame Relay network (10) wherein the Frame Relay network includes at least a hub (12 or 14) which is linked to each one of a set of spokes (16, 18, 24 or 20, 22, 24) by a Permanent Virtual Circuit (PVC) identified by a first Data Link Connection Identifier (DLCI) associated with the hub and a second DLCI associated with the spoke, the hub and the set of spokes defining an IP subnet having a subnet address, and each spoke having an inverse ARP table in which the first DLCI identifying a PVC is mapped with the IP address of the hub as entry. The method comprises automatically entering an entry into the inverse ARP table which defines the first DLCI being mapped with a default IP address identifying the hub as destination for any frame addressed to one or several spokes of the subnet.

Abstract: An IP network over a partially meshed Frame Relay network wherein the Frame Relay network includes at least a hub which is linked to each one of a set of spokes by a Permanent Virtual Circuit (PVC) identified by a first Data Link Connection Identifier (DLCI) associated with the hub and a second DLCI associated with the spoke The hub and the set of spokes define an IP subnet having a subnet address. Each spoke has an inverse ARP table in which the first DLCI identifying a PVC is mapped with the IP address of the hub as entry. The inverse ARP table of each spoke comprises, further to the entries corresponding to the IP addresses of the hubs to which the spoke is linked, at least a default entry identifying the subnet address whereby any frame the IP address of which corresponds to a spoke is routed to the hub by scanning inverse ARP table.

Abstract: 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.

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: Auto-adaptive method of load balancing in a data transmission system wherein one active station (32) amongst a plurality of stations requests the access to the resources of a host (10), the active station being connected to a connected-oriented network linked to host (10) by means of a plurality of communication controllers (12, 14, 16) identified by the station (32) with the address of host (10), the connected-oriented network implementing a protocol in which route discovery frames are sent from the station (32) to all the communication controllers (12, 14, 16) and response frames are sent back with a predefined delay from each one of the communication controllers to the station (32), whereby the station (32) selects the route defined by the first received response frame, this method being characterized in that the delay to apply to the response frame is at each moment dynamically defined by using a logarithmic function of the current number of active stations.

Abstract: A communication system speeds up digital traffic between nodes. The traffic is organized into data frames flowing over network high and low speed links attached to entry and exit ports of the nodes. Low speed modules connect the low speed links to a high speed switch. Router dispatch modules connect the high speed switch to a node attached to a high speed link for forwarding each data frame toward a dynamically selected target low speed module via the high speed switch, such that the dynamic selection of the target low speed module is based on detection of the module with the least load. At least one main router is attached to the high speed switch for storing a routing table to enable the targeted low speed module to orient one of the frames toward a right node exit port.

Abstract: A method for improving next hop selection between internet routers (R) defined by their respective IP addresses. A source is identified by a source IP address and a source port identification. A destination or target is defined by a target port identification. Equivalent routes toward the destination host are identified conventionally. Each of the equivalent routes is defined by next router IP address. The source IP address, source port identification and target port identification are logically combined to derive a connection identifier (HO) for a first router common to all paths. An set of additional logical operations are performed to derive next hop selection identifiers. Final next hop route selection is based on predefined criterion.