British Telecommunications Public Limited Company

British Telecommunications Corporation

Peter Hovell

John R King

John Patterson

Robert J Briscoe

Arnaud Jacquet

Gabriele Corliano

David J Songhurst

John Robert King

David John Songhurst

Robert John Briscoe

Communication between a network device in a first network and a network device in a second network is provided, where the first network operates in accordance with a first communication protocol and the second network operates in accordance with a second communication protocol. An alias is assigned to a target network device in the first network, the alias being compatible with the communication protocol of the second network The assigned alias is translated to an address for a target network device, the translated address being compatible with the communication protocol of the first network. Apparatus, for assigning the alias and for translating it are separately addressable in one or both of the networks, and the assigned alias corresponds to an address of the translating apparatus, such that, when a network device in the second network sends one or more communication(s) using an address including the assigned alias, each communication is routed to the translator, whereupon the translator translates the alias into the address of the target network device in the first network and sends the communication(s) into the first network.

Inter-network address translator that is separately addressable from address alias assignment process

An address resolver system that assists a node in an IPv6 network to select an address for connectivity with a node in an IPv4 network when both DSTM and NAT-PT transition mechanisms are available. Native connectivity can be achieved by preferring an encapsulation or tunnelling mechanism such as DSTM where possible over a translation mechanism such as NAT-PT. A range of encapsulation and translation mechanisms are envisaged. The resolver determines capabilities of the node and of the application that requires the address in order to make the selection.

System for selecting a connectivity mechanism

The invention provides a coordination layer of coordinating entities provided intermediate the admission control interfaces of the transport network domains, and any QoS signaller which signals QoS requests on behalf of the application layer. The coordination layer acts to distribute an admission control request across the multiple transport network domains by the use of coordination request messages containing the admission control request being forwarded through the coordination layer of coordinating entities. At each coordinating entity the admission control request is passed on to the admission control interface of the transport network which the coordinating entity serves, and an admission control response obtained. This admission control response is then combined with admission control responses from the other domains which are propagated through the coordination layer via coordination messages. The result is that the coordination layer acts to combine the various admission control responses into a combined response, which can be provided back to the QoS signaller (or other requesting entity). Thus, coordination of admission control across multiple transport network domains is achieved, without a QoS signaller having to contact each individual domain.

Method and system for coordination of admission control in transport networks

Packet forwarding apparatus has an input for receiving packets; a packet classifier arranged in operation to read a class indication in received packets and in dependence thereon to pass packets to a class-based policer associated with the class indicated; a plurality of class-based policers, each operable to assign a provisional indication to packets of the associated class in response to a measure of the load presented by packets of the class exceeding a predetermined class-based threshold; a multi-class policer operable to receive provisionally-indicated packets processed by the class-based policers, and to assign a congestion indication to packets having the provisional indication in response to congestion arising at the packet forwarding apparatus; and an output for presenting packets processed by the multi-class policer for onward transmission from the apparatus.

Packet forwarding

An interface for use between two IPv6 domains separated by an IPv4 domain includes a protocol converter, an encapsulator/un-encapsulator and a controller.

Packet network interfacing

A tunnel is established across an IPv4 domain for the transport of packets from a source host on one IPv6 domain to a destination host on another IPv6 domain, there being respective interfaces between the IPv4 domain and the IPv6 domains.

Growing community of inventors

Woodbridge, United Kingdom

Peter Hovell