Abstract: A telecommunications system comprises an asynchronous transfer mode (ATM) network having uncommitted bandwidth, and a plurality of adaptive grooming routers (AGR) coupled to the network. The AGRs comprise a group adapted to function as a virtual transit exchange whose fabric and control are distributed over the group. The visual comprising the AGRs incorporates independent connection control and call routing functions and has means for determining the current system status whereby to set up narrow band connections across the ATM network based on that status determination.

Abstract: A telecommunications system comprises an asynchronous transfer mode (ATM) network having uncommitted bandwidth, and a plurality of adaptive grooming routers (AGR) coupled to the network. The AGRs comprise a group adapted to function as a virtual transit exchange whose fabric and control are distributed over the group. The visual comprising the AGRs incorporates independent connection control and call routing functions and has means for determining the current system status whereby to set up narrow band connections across the ATM network based on that status determination.

Abstract: To ensure an effective mechanism for disaster recovery, system migration and network enlargement, a communication system (FIG. 6) comprises a narrowband-to-broadband interface (300) having a plurality of network adaptors (302-306) interconnected to a switch (314-316) that provides access to a plurality of virtual channels (318-321) supported by a broadband network. The plurality of network adaptors (302-306) are also coupled to a plurality of trunks (308-312) that each support at least one of a plurality of different communication functions. At least two call servers (324-326) are independently coupled to the narrowband-to-broadband interface (300) and are arranged to control interconnection of trunks to virtual channels, while each of the at least two call servers is responsible for controlling interconnections of group of trunks that share a common communication function within each group. Communication system functionality is therefore separated between the at least two call servers.

Abstract: Narrowband subscriber terminals (40,52,58) of different narrowband networks are interconnected via a broadband network (48) that supports dissimilar signaling protocols to those maintained on the respective narrowband networks (40,52,58). A call server in a first narrowband network (40), in response to a call (100) from a first subscriber terminal (12) to a second subscriber terminal (68) in a second but different narrowband network (52), selects a phantom trunk (202) between the two networks. The phantom trunk has a unique circuit identity, which circuit identify is used in a first instance to relay to the second network an address of the second subscriber terminal (68). Then, in a second instance, the unique circuit identify is used to relay to the second network an address of the first subscriber terminal (68).

Abstract: Traffic from a number of different service type users is multiplexed into minicells for transmission over an ATM link. Service type information is transmitted in a service specific field and is stored. This stored information is used to derive length information to delineate the different length user minicells. The technique occupies less bandwidth than the conventional methods for transmitting cell length information.

Abstract: The invention provides a plurality of core nodes establishing a multi-service transport network, and service nodes each coupled to a core node for providing access to the transport network. A network management system is arranged to define and manage one or more virtual public/private networks within the communications network. Groups of core nodes are configured as abstract nodes within which any available path may be selected to achieve a requested connection. End to end label switched paths are established via the management system by specifying a series of abstract nodes.

Abstract: A method for enabling traffic to be carried between devices which may use different communications protocols employs a multimedia service provide, which provides an interface between two devices or between a device and a multimedia network. The service provider enables conversion between the communications protocols used by the two devices by comparing the protocols used by each device and, preferably, carrying out a conversion which minimises the amount of traffic conversion required. If two devices are interfaced to an intermediate network via respective service providers, the service providers preferably negotiate before communication between the devices begins to ensure, if possible, that traffic conversion is only performed by one of the service providers.

Abstract: To ensure an effective mechanism for disaster recovery, system migration and network enlargement, a communication system (FIG. 6) comprises a narrowband-to-broadband interface (300) having a plurality of network adaptors (302-306) interconnected to a switch (314-316) that provides access to a plurality of virtual channels (318-321) supported by a broadband network. The plurality of network adaptors (302-306) are also coupled to a plurality of trunks (308-312) that each support at least one of a plurality of different communication functions. At least two call servers (324-326) are independently coupled to the narrowband-to-broadband interface (300) and are arranged to control interconnection of trunks to virtual channels, while each of the at least two call servers is responsible for controlling interconnections of group of trunks that share a common communication function within each group. Communication system functionality is therefore separated between the at least two call servers.

Abstract: A telecommunications network architecture provides transport and switching of user services, particularly PSTN/ISDN services. In the network, connections are set up between end points which typically comprise narrow band exchanges serving subscribers. Calls are set up between the end points via call servers using e.g. ISUP signalling between the end points or exchanges and the call servers. The call servers set up connections via a concatenated series of paths or tunnels across an intermediate MPLS network via media gateways serving respective nodes in the MPLS network. User information packets are carried across the MPLS network by the attachment of an appropriate label, this label being removed on egress from the MPLS network to recover the original packet.

Abstract: Traffic from a number of different service type users is multiplexed into minicells for transmission over an ATM link. Service type information is transmitted in a service specific field and is stored. This stored information is used to derive length information to delineate the different length user minicells. The technique occupies less bandwidth than the conventional methods for transmitting cell length information.

Abstract: Traffic from a number of different service type users is multiplexed into minicells for transmission over an ATM link. Service type information is transmitted in a service specific field and is stored. This stored information is used to derive length information to delineate the different length user minicells. The technique occupies less bandwidth than the conventional methods for transmitting cell length information.

Abstract: Narrowband subscriber terminals (40,52,58) of different narrowband networks are interconnected via a broadband network (48) that supports dissimilar signalling protocols to those maintained on the respective narrowband networks (40,52,58). A call server in a first narrowband network (40), in response to a call (100) from a first subscriber terminal (12) to a second subscriber terminal (68) in a second but different narrowband network (52), selects a phantom trunk (202) between the two networks. The phantom trunk has a unique circuit identity, which circuit identify is used in a first instance to relay to the second network an address of the second subscriber terminal (68). Then, in a second instance, the unique circuit identify is used to relay to the second network an address of the first subscriber terminal (68).

Abstract: A network arrangement for transporting service (Servco) traffic between terminals via an asynchronous path comprises a servco access layer incorporating multimedia gateways for access by said terminals, an asynchronous network layer, a service layer incorporating adaptation layer switches each coupled to the network layer, and a transport layer providing a connection medium between the adaptation layer switches. The Servco traffic is carried in ATM minicells over the network layer. Delineation of the minicells is effected by searching the received ATM stream for a valid code word indicating the start of a minicell, and, for that minicell and subsequent minicells, determining length information so as to determine the start of each next minicell.

Abstract: A connectionless communications network includes a number of low earth orbit (LEO) satellite nodes. Motion of the satellites constantly changes the topology of the network. A virtual model of the network having fixed virtual nodes, is maintained in a connection control system. This virtual model is used to control the route that traffic will take through the real network. As topology changes happen in the network then the virtual nodes of the model become embodied by different real nodes and communicate their virtual identity to connected nodes. Routing of the traffic is performed with reference to the virtual network so that routing follows the current embodiment of the virtual network.

Abstract: Narrowband subscriber terminals (40,52,58) of different narrowband networks are interconnected via a broadband network (48) that supports dissimilar signalling protocols to those maintained on the respective narrowband networks (40,52,58). A call server in a first narrowband network (40), in response to a call (100) from a first subscriber terminal (12) to a second subscriber terminal (68) in a second but different narrowband network (52), selects a phantom trunk (202) between the two networks. The phantom trunk has a unique circuit identity, which circuit identify is used in a first instance to relay to the second network an address of the second subscriber terminal (68). Then, in a second instance, the unique circuit identify is used to relay to the second network an address of the first subscriber terminal (68).

Abstract: In a packet communications network, e.g. an IP network, connection oriented services are carried in user tunnels which are set up in engineering tunnels established across the network. This provides end to end connectivity without the need for individual packet routing at the intermediate network nodes.

Abstract: A telecommunications system comprises an asynchronous transfer mode (ATM) network having uncommitted bandwidth, and a plurality of adaptive grooming routers (AGR) coupled to the network. The AGRs comprise a group adapted to function as a virtual transit exchange whose fabric and control are distributed over the group. The vitual comprising the AGRs incorporates independent connection control and call routing functions and has means for determining the current system status whereby to set up narrow band connections across the ATM network based on that status determination.

Abstract: Voice and media services are provided over an IP network incorporating a plurality of nodes and in which connection oriented traffic is transported in tunnels via said nodes. SS7 signalling is provided between nodes. The voice and media components are multiplexed to form a point to point protocol (PPP) session which is switched end to end across the network under the control of the signalling.

Abstract: To segregate functionality and to eliminate redundancy in service logic and associated hardware that together control the interconnection of narrowband trunk circuits (252-256) and broadband virtual channels (258-262) of a mixed node communication system (FIG. 5), a switch fabric (16) has an associated memory (280) that contains a pre-provisioned table of mappings between narrowband trunk circuits (DS-0s) and broadband virtual channel identities. Therefore, to establish an end-to-end connection, the switch fabric (16) searches the pre-provisioned table (280) for an available connection and then performs the necessary cross-connection between the narrowband trunk circuit is (252-256) and the broadband virtual channel (258-262). The mappings principally relate to the narrowband-to-switch fabric interface and, as such, avoid the requirement for UNI signalling translation and negotiation, although the mappings may also include the broadband-to-switch fabric interface.

Abstract: A telecommunications system comprises an asynchronous transfer mode (ATM) network having uncommitted bandwidth, and a plurality of adaptive grooming routers (AGR) coupled to the network. The AGRs comprise a group adapted to function as a virtual transit exchange whose fabric and control are distributed over the group. The virtual comprising the AGRs incorporates independent connection control and call routing functions and has means for determining the current system status whereby to set up narrow band connections across the ATM network based on that status determination.