British Telecommunications Public Limited Company

British Telecommunications Corporation

John R King

Peter Hovell

John Patterson

Benjamin P Niven-Jenkins

Andrew Lord

Roger George Buck

A wavelength is selected for use in transmitting optical data along a path in an optical network. Wavelengths that are available for use end-to-end along the path are found, the wavelengths that are available on each link attached to each node on the path are found and a wavelength that is available end-to-end and that is more available on the links attached to the nodes is selected.

Wavelength selection

A path is established through an optical communications network. One or more partial paths are evaluated according to a first criterion, and candidate end-to-end paths are then evaluated according to a second criterion. The end-to-end path evaluation disregards candidate end-to-end paths that include partial paths not meeting the first criterion. A path is established by selecting one of the candidate end-to-end paths on the basis of the second criterion.

Path establishment

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

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.

A method of communications employs a communications protocols defining respective responses to predetermined events. The protocol is separated into a first group of behaviours defining responses to corresponding first, relatively frequently occurring, events, and a second group of behaviours defining responses to corresponding first, relatively frequently occurring, events, and a second group of behaviours defining responses to corresponding second, relatively infrequently occurring events. The first group is stored at a user communications terminal. At least the second group is stored at a store remote from the user terminal, and interconnected therewith via a communications channel. Communication is established from the user terminal using first events. On detecting an event other than one of said the first events at the user terminal, event holding data is signaled from the store to the user terminal; and communication is established from the user terminal using the event-handling data.

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Woodbridge, United Kingdom

John R King