(19)

(11)

EP 1 074 112 A1

(12)

(43) Date of publication: 07.02.2001 Bulletin 2001/06 (21) Application number: 99918086.2 (22) Date of filing: 15.04.1999

(51) International Patent Classification (IPC)7: H04L 7/00 (86) International application number: PCT/GB9901/159 (87) International publication number: WO 9955/038 (28.10.1999 Gazette 1999/43)

(84) Designated Contracting States: DE FR GB (30) Priority: 21.04.1998 GB 9808491 05.06.1998 GB 9812162 (71) Applicant: BRITISH TELECOMMUNICATIONS public limited company London EC1A 7AJ (GB)	(72) Inventors: COTTER, David Woodbridge,Suffolk IP12 4JN (GB) ELLIS, Andrew David Ipswich,Suffolk IP8 3RW (GB) (74) Representative: Roberts, Simon Christopher  BT Group Legal Services,Intellectual Property Department,8th Floor, Holborn Centre120 Holborn London, EC1N 2TE London, EC1N 2TE (GB)