British Telecommunications Public Limited Company

British Telecommunications Corporation

Hitachi, Ltd.

Alan McGuire

Neil Harrison

Hideaki Tsushima

Peter E Barnsley

Justin Kang

Sergio F O Inglima

Anthony J Flavin

A method of generating a generic framing procedure hierarchy comprising processing a first generic framing procedure frame to determine the overall length of the generic framing procedure frame, mapping the frame into the generic framing procedure payload area of a second generic framing procedure frame at the next level of the generic framing procedure hierarchy, whereby information enabling the size of the generic framing procedure payload remaining after that frame has been extracted is captured in the header fields of the generic framing procedure frame into which the first frame is encapsulated, and wherein the generic framing procedure header indicates whether there are more frames left in the mapping hierarchy when de-encapsulating (i.e., running down) the generic framing procedure frame stack by providing an indicator at level N of the hierarchy that at the level N&#x2212;1 there is a generic framing procedure frame to extract.

Adaptation scheme for communications traffic

A method of reducing the bandwidth required to send a plurality of client traffic frames over a plurality of carrier communications networks is disclosed. Related communications system, data stores and boundary nodes are also disclosed.

Multiple carrier compression scheme

A communications network provides a carrier Ethernet service without requiring the client signal to be identified by an Ethertype in a carrier Ethernet frame. A plurality of differing types of client signals can thus be encapsulated within the same carrier Ethernet service channel by using a generic framing procedure adaptation layer. The client signals are adapted for encapsulation within the carrier Ethernet frames by mapping the client signal within a generic framing procedure adaptation layer signal and then by mapping the generic framing procedure adaptation layer signal into the carrier Ethernet signal. As the client signal is identified within said generic framing procedure signal only a generic framing signal Ethertype is required. The mapping protocol enables a single Ethernet frame to carry a plurality of client signals.

Client/server adaptation scheme for communications traffic

A method of partitioning the header stack of a data packet, the header stack conforming to a label switching protocol, the method comprising: receiving the packet at an edge mode of a routing domain in the communication system; and processing the label header stack at the edge node to add a new stack entry having a label field comprising a value which delimits the header stack entries between a stack domain configurable by the node belonging to a first routing domain of the label switching protocol and at least one other stack domain configurable by a node belonging to another routing domain of the communications system.

MPLS transport network scheme

A method of implementing a p-cycle protection scheme for a communications network comprising a plurality of nodes and interconnecting communications links along which Ethernet traffic is forwarded in a connection-oriented manner. The method comprises for each said Ethernet node in the communications network determining a label associated with each connection-oriented Ethernet path along one or more links in said communications network for which an entry exists in a forwarding table of Ethernet switching apparatus located at said Ethernet node and mapping a plurality of said paths individually identified by said respective labels, to another path defining a p-cycle between logically adjacent nodes in said communications network, wherein each said p-cycle is provisioned in the same layer as said Ethernet traffic.

In-layer ethernet p-cycle protection scheme

A communications system in which carrier Ethernet conveys a plurality of differing types of client signals encapsulated with a generic framing procedure adaptation layer. The client signals are adapted for encapsulation within the carrier Ethernet frames by mapping the client signal within an generic framing procedure adaptation layer signal and then by mapping the generic framing procedure adaptation layer signal into the carrier Ethernet signal, the client signal being identified within the generic framing procedure signal.

A communications network including nodes which permit networks to be tunnelled across intermediate networks. The present invention has application, in particular, to SDH networks, SONET and OTN. The content of entities for transportation across an existing network are mapped into a series of subframes and are virtually concatenated across the network. Each subframes is assigned a sequence indicator, which allows the original entity to be assembled at a remote node.

Method and apparatus for tunnelling data in a network

Cross-connect for an optical network

A wavelength division multiplex communication system comprises a head station (2) and a plurality of terminal stations (1) interconnected by an optical fibre cable (3). The head station (2) transmits continuous wave modulated wavelengths (.lambda..sub.1 -.lambda..sub.k), and a signalling wavelength (.lambda..sub.0) which is used to indicate, in each time slot, which wavelengths in the following time slot are available for transmission. Each terminal station (1) is arranged to receive the signalling wavelength, to determine therefrom whether the next time slot contains any data packets for that terminal station and, if so, to receive the packets. The terminal station (1) is arranged, if it has a data packet to transmit, to determine from the signalling wavelength whether the next time slot already contains data packets for the destination station and, if so, to avoid data collision by not transmitting its own data packet. The terminal station (1) then determines a free wavelength (.lambda..sub.q) from the signalling wavelength (.lambda..sub.0), modulates the free wavelength with the data packet it is to transmit, and modifies the signalling wavelength.

WDM network with control wavelength

A wavelength division multiplex communications system has a head station and a plurality of terminal stations interconnected by an optical fiber cable. The head station transmits CW modulated wavelengths (.lambda.-.sub.1 -.lambda..sub.k), and a signalling wavelength (.lambda..sub.0) which is used to indicate, in each time slot, which wavelengths in the following time slot are available for transmission. Each terminal station is arranged to receive the signalling wavelength (.lambda..sub.0), to determine therefrom whether the next time slot contains any data packets for that terminal station and, if so, to receive the packets. Each terminal station is arranged, if it has a data packet to transmit, to determine from the signalling wavelength (.lambda..sub.0) whether the next time slot already contains data packets for the destination station and, if so, to avoid data collision by not transmitting its own data packet. The terminal station then determines a free wavelength (.lambda..sub.t) from the signalling wavelength (.lambda..sub.0), modulates the free wavelength with the data packet it is to transmit, and modifies the signalling wavelength.

Growing community of inventors

Felixstowe, United Kingdom

Alan McGuire