Abstract: Virtual dedicated voice connections between parties to a packet-switched system can be created by reserving capacity for such connections in the packet-switched system. The capacity reservable by any one party is limited to prevent over-subscription of resources in the packet switched. The system incorporates a call admission control processor for controlling access to the packet-switched call routing system such that a voice call attempt is successful only if capacity for such a dedicated connection has previously been reserved. The capacity reserved for the virtual connections is made available for use by other traffic when not required for voice sessions.

Abstract: Virtual dedicated voice connections between parties to a packet-switched system can be created by reserving capacity for such connections in the packet-switched system. The capacity reservable by any one party is limited to prevent over-subscription of resources in the packet switched. The system incorporates a call admission control processor for controlling access to the packet-switched call routing system such that a voice call attempt is successful only if capacity for such a dedicated connection has previously been reserved. The capacity reserved for the virtual connections is made available for use by other traffic when not required for voice sessions.

Abstract: Virtual dedicated voice connections between parties 18, 19 to a packet switched system can be created by reserving capacity for such connections in the packet switched system. The capacity reservable by any one party is limited, to prevent oversubscription of resources in the packet switched. The system incorporates a call admission control processor 12, 17 for controlling access to the packet switched call routing system such that a voice call attempt is successful only if capacity for such a dedicated connection has previously been reserved. The capacity reserved for the virtual connections is made available for use by other traffic when not required for voice calls.

Abstract: A virtual local area network 2 provides a multicasting facility between a first termination point 1 and a plurality of other termination points 3, 4, wherein a source identifier associated with the first termination point 1 is advertised over the network with an indication that it relates to the multicast, and the other termination points 3, 4 select transmissions associated with the said source identifiers to be advertised to the other termination points such that the other termination points 3, 4 can identify and select data transmissions relating to the multicast. The data may also be transmitted by way of another network 9 as a backup, the termination points 3, 4 preferentially selecting data transmissions from the virtual local area network 2 by identification of a weighting applied to those transmissions sent via the VLAN.

Abstract: A virtual private data network is overlain on an internet connection to allow prioritisation of connection between two or more specified terminations over a switched network, thereby minimising latency in the system. Data to be transmitted between the specified terminations is identified by a weighting prefix and its routing is prioritised over other data for the same destination termination.

Abstract: A virtual private data network is overlain on an internet connection to allow prioritisation of connection between two or more specified terminations over a switched network, thereby minimising latency in the system. Data to be transmitted between the specified terminations is identified by a weighting prefix and its routing is prioritised over other data for the same destination termination.

Abstract: A virtual local area network 2 provides a multicasting facility between a first termination point 1 and a plurality of other termination points 3, 4, wherein a source identifier associated with the first termination point 1 is advertised over the network with an indication that it relates to the multicast, and the other termination points 3, 4 select transmissions associated with the said source identifiers to be advertised to the other termination points such that the other termination points 3, 4 can identify and select data transmissions relating to the multicast. The data may also be transmitted by way of another network 9 as a backup, the termination points 3, 4 preferentially selecting data transmissions from the virtual local area network 2 by identification of a weighting applied to those transmissions sent via the VLAN.