US 7,512,983 B2
Method and apparatus for network security
Fabrice T P Saffre, Kesgrave (United Kingdom)
Assigned to British Telecommunications PLC, London (United Kingdom)
Appl. No. 10/507,892
PCT Filed Mar. 25, 2003, PCT No. PCT/GB03/01274
§ 371(c)(1), (2), (4) Date Sep. 17, 2004,
PCT Pub. No. WO03/084170, PCT Pub. Date Oct. 09, 2003.
Claims priority of application No. 0207400.3 (GB), filed on Mar. 28, 2002; and application No. 02252767 (EP), filed on Apr. 19, 2002.
Prior Publication US 2005/0149728 A1, Jul. 07, 2005
Int. Cl. G06F 11/00 (2006.01)
U.S. Cl. 726—25  [726/3; 726/11; 726/26; 713/153; 713/166] 18 Claims
OG exemplary drawing
 
1. A method of determining an alert level of a node in a network of other nodes that may be trusted nodes or non-trusted nodes, the method comprising:
receiving one or more beacon signals from one or more other nodes in the network, said beacon signal providing to the node an indication of the alert level of the other node and/or an indication of whether the other node is a trusted or non-trusted member of the network; and
determining an alert level for the node based on the alert level in the or each received beacon signals and/or the indication of the trusted or non-trusted nature of the other node;
wherein the beacon signal from other nodes are collected over a predetermined period and the alert level rises automatically if the proportion of the received beacon signals that are non-valid exceeds a predetermined threshold within the predetermined period.