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: 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: In a packet communications network system, a border gateway protocol is employed to route an information packet from a source in a first autonomous system via a first label switched path to a destination in a second autonomous system via first and second border routers at an interface between the first and second autonomous systems. A label stack attached to the packet identifies both a forwarding interface for the packet and a forwarding behaviour at that interface. This provides a mapping from the first label switched path on to a second label switched path to the destination in the second autonomous system. Preferably, the destination router in the second autonomous system returns to the source router in the first autonomous system a two-label stack identifying first and second paths across the first and second autonomous systems respectively.

Abstract: A label switched path is determined in a communications multi-service network comprising a plurality of nodes interconnected via quality of service capable tunnels to provide a QoS guarantee for a session in which resource availability from the network edge to multiple central stages and resource availability from the multiple central stages to the destination edge are established. A series of quality of service capable tunnels is selected by offering a plurality of candidate central stages to the destination edge and allowing the destination edge to select a complete path across the network. A label stack comprising a set of four labels is attached to a payload to define a selected sequence of tunnels.

Abstract: Label switched paths are installed in a label switched communications packet network. Paths are selected by defining and installing partial routes each having two or more paths such that an end-to-end route across the network can be defined as the concatenation of two partial routes. Signalling to select a path is effected by sending a path message from an end point to a first virtual router, determining a path from the end point to the virtual router, and forwarding an identity of the path to a second virtual router. The second virtual router determines a routing vector across the network, and returns information identifying the routing vector to the first virtual router.

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: In a label switch communications network, a third level of label is employed in conjunction with a dynamic multiplex constraint-based routed label switched path (CR-LSP) in order to achieve implicit switching at nodes within the network. Implicit switching occurs when a switching function takes place at a node without the need for any control function being required at that node. A three-layer label stack provided at the edge of the network achieves end-to-end connection oriented behaviour with guaranteed Quality of Service. The use of the three-layer label stack concentrates the control of the network to the two edges of the network and a single central switching stage of the network.

Abstract: A network arrangement for delivering IP services to subscribers includes a core network, a plurality of label switched media gateways coupled to the network and each providing an interface for one or more subscriber terminals. Call servers associated with the network are used to establish connections between pairs of gateways, these connections being routed across the core network via tunnels established therein. The tunnels are exclusively reserved for traffic between the label switched media gateways so as to provide security of that traffic from third party access and to provide a guaranteed quality of service. Because traffic is accepted into a tunnel only if bandwidth is available in that tunnel, firm and meaningful quality of service guarantees can be given to users.

Abstract: A communications multi-service network arrangement for transporting information packets from a user station to a destination comprises a label switched core network constituted by a plurality of abstract nodes interconnected by tunnels. Each abstract node comprises one or more real nodes. An access network provides user access to the core network. A route across the core network comprises a plurality of label switched path sections specified in terms of a sequence of abstract nodes, the route being identified by a label stack identifying a quality of service capable connection from the end station via the access network to the core network and across the core network to a destination.

Abstract: In a packet communications network system, a border gateway protocol is employed to route an information packet from a source in a first autonomous system via a first label switched path to a destination in a second autonomous system via first and second border routers at an interface between the first and second autonomous systems. A label stack attached to the packet identifies both a forwarding interface for the packet and a forwarding behaviour at that interface. This provides a mapping from the first label switched path on to a second label switched path to the destination in the second autonomous system. Preferably, the destination router in the second autonomous system returns to the source router in the first autonomous system a two-label stack identifying first and second paths across the first and second autonomous systems respectively.

Abstract: Label switched paths are installed in a label switched communications packet network. Paths are selected by defining and installing partial routes each comprising two or more paths such that an end-to-end route across the network can be defined as the concatenation of two partial routes. Signalling to select a path is effected by sending a path message from an end point to a first virtual router, determining a path from the end point to the virtual router, and forwarding an identity of the path to a second virtual router. The second virtual router determines a routing vector across the network, and returns information identifying the routing vector to the first virtual router.

Abstract: A flexible and equitable PCN/PSTN interconnection strategy between a communications network having mobile subscribers, such as a PCN network, and a PSTN whereby to form a communication system in which multiple tariffs can be applied, the tariff applied being determined by the actual location of the mobile subscriber involved in a call. The PSTN (2, 6, 9, 10) is not given total access to the PCN (1, 5, 8, 11) location registers, rather a PSTN to PCN call is via a PCN gateway (5) which does have access to the location registers. The gateway (5) accepts zonal calls with which are associated one tariff (zonal interconnect 4) but for, for example, local or interzonal calls, it provides drop back messages to the PSTN to arrange for appropriate rerouting to other gateways (1, 8) of the PCN which have different tariffs associated therewith (local interconnect 3, interzonal interconnect 7).

Abstract: A base station controller (BSC) personal communications network (PCN), which can for example be based on GSM, has associated with it a local PSTN network and is such that local calls between mobile subscribers and the local PSTN network can be made without involving a remote mobile-services switching centers (MSC), thereby permitting a cheap local call tariff to be employed whilst preserving the interfaces e.g. the GSM Abis and A interfaces. The BSC is intelligent and includes a BSC function, a local MSC function and a location register which slaves mobile subscriber location information from the MSC location registers.