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EP 1 080 570 A1

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(43) Date of publication: 07.03.2001 Bulletin 2001/10 (21) Application number: 99925146.5 (22) Date of filing: 26.05.1999

(51) International Patent Classification (IPC)7: H04L 29/06, H04Q 3/00, H04L 12/18 (86) International application number: PCT/GB9901/662 (87) International publication number: WO 9962/239 (02.12.1999 Gazette 1999/48)

(84) Designated Contracting States: DE FR GB NL SE (30) Priority: 26.05.1998 GB 9811264 26.05.1998 EP 98304143 (71) Applicant: BRITISH TELECOMMUNICATIONS public limited company London EC1A 7AJ (GB)

(72) Inventors: ELLIS, Martin, John Swindon SN3 1PT (GB) FARR, Jeffrey, Roger Ipswich IP3 8RY (GB) JAMES-BELL, Duncan, Charles Swindon SN2 2WF (GB) CRESWELL, Daniel, Christopher Reading RG2 8HP (GB) HOSKING, Michael, Robert Martlesham Heath,Ipswich IP5 3TU (GB) SMITH, Christopher, John S-118 28 Stockholm (SE) (74) Representative: Roberts, Simon Christopher et al BT Group Legal Services,Intellectual Property Department,8th Floor, Holborn Centre120 Holborn London, EC1N 2TE London, EC1N 2TE (GB)