The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 21, 1999
Filed:
Sep. 16, 1994
Dipak Mohanlal Soni, London, GB;
3Com Corporation, Santa Clara, CA (US);
Abstract
A ring data network (such as a token ring network) is divided by a security unit (1) into first and second segments (6 and 8). The second segment (8) typically corresponds to one security group in the network. Logic in the security unit reads appropriate parts of each frame (typically the two address segments) to determine whether it is appropriate to forward the frame to the next segment of the ring. If the frame does not need to go to the next segment, or is not authorized to do so, then the security unit forwards instead a modified form of the frame in which its data cannot be read (except possibly by the security unit itself). In most cases the data content of the frame will be stored in the security unit. When the modified frame returns to the security unit at its second input port (4), the original frame can (if appropriate) be reconstructed, typically by reading its data content from a store in the security unit. In this way, the frame is returned to the secure group at the same time and in the same form as if it had travelled around the first segment of the ring, but there is no opportunity for stations in the first segment to eavesdrop upon the frame.