(19)

(11)

EP 1 051 825 A1

(12)

(43) Date of publication: 15.11.2000 Bulletin 2000/46 (21) Application number: 99902701.4 (22) Date of filing: 29.01.1999

(51) International Patent Classification (IPC)7: H04L 29/08, G06F 15/02, H04L 29/06 (86) International application number: PCT/GB9900/311 (87) International publication number: WO 9939/488 (05.08.1999 Gazette 1999/31)

(84) Designated Contracting States: DE ES FR GB IT NL SE (30) Priority: 29.01.1998 EP 98300658 29.01.1998 GB 9801928 (71) Applicant: BRITISH TELECOMMUNICATIONS public limited company London EC1A 7AJ (GB)	(72) Inventor: FLYNN, Jason Stuart Felixstowe,Suffolk IP11 9NF (GB) (74) Representative: Lidbetter, Timothy Guy Edwin et al BT Group Legal Services,Intellectual Property Department,8th Floor, Holborn Centre,120 Holborn London EC1N 2TE London EC1N 2TE (GB)