(19)

(11)

EP 0 997 021 A1

(12)

(43) Date of publication: 03.05.2000 Bulletin 2000/18 (21) Application number: 98932319.1 (22) Date of filing: 13.07.1998

(51) International Patent Classification (IPC)7: H04L 29/06, H04L 12/66, H04L 12/64 (86) International application number: PCT/GB9801/910 (87) International publication number: WO 9904/540 (28.01.1999 Gazette 1999/04)

(84) Designated Contracting States: DE FR GB (30) Priority: 14.07.1997 GB 9714793 (71) Applicant: MADGE NETWORKS LIMITED Buckinghamshire HP8 4AH (GB)	(72) Inventors: GREATWOOD, Duncan MacDougall Ashwell,Herts SG7 8PG (GB) CROFT, Stephen, John Maidenhead,Berkshire SL6 6LB (GB) (74) Representative: Lawrence, Peter Robin Broughton et al GILL JENNINGS & EVERY,Broadgate House,7 Eldon Street London EC2M 7LH London EC2M 7LH (GB)