(19)

(11)

EP 1 000 488 A1

(12)

(43) Date of publication: 17.05.2000 Bulletin 2000/20 (21) Application number: 98935214.1 (22) Date of filing: 24.07.1998

(51) International Patent Classification (IPC)7: H04L 12/58, G06F 17/60, G06F 17/20 (86) International application number: PCT/GB9802/216 (87) International publication number: WO 9907/118 (11.02.1999 Gazette 1999/06)

(84) Designated Contracting States: DE ES FR GB IT NL (30) Priority: 30.07.1997 EP 97305713 (71) Applicant: BRITISH TELECOMMUNICATIONS public limited company London EC1A 7AJ (GB)	(72) Inventors: KANEEN, Edward, Noble IpswichSuffolk IP5 2GL (GB) BIRNEY, Alexander, Philip HuntingdonCambridgeshire PE18 9EB (GB) (74) Representative: Nash, Roger William et al BT Group Legal Services,Intellectual Property Department,Holborn Centre, 8th Floor,120 Holborn London EC1N 2TE London EC1N 2TE (GB)