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:
Feb. 01, 1994
Filed:
Oct. 01, 1992
Henry Yang, Andover, MA (US);
Jerry Hutchison, Littleton, MA (US);
William R Hawe, Pepperell, MA (US);
G Paul Koning, Brookline, NH (US);
Digital Equipment Corporation, Maynard, MA (US);
Abstract
An apparatus to detect stations having duplicated addresses, the stations of the type connected in a computer communications network, the stations of the type capable of having an assigned address and having a list of addresses for comparison with a destination address field of a frame detected on the network is disclosed. The apparatus does a transmit self test, and sets a self indicator to 'pass' in the event that the self test frame is received, and sets the self indicator to 'timeout' in the event that a timeout occurs. The apparatus does a neighbor response test, and sets a neighbor indicator to 'timeout' in the event that a timeout occurs, and sets the neighbor indicator to 'pass' in the event that a received response frame indicates no destination address match, and sets the neighbor indicator to 'fail' in the event that a received response frame indicates that a destination address match did occur. The apparatus tests both the self indicator and the neighbor indicator, and in response to the testing of the self indicator and the testing of the neighbor indicator sets a duplicate address indicator in one of three states, a first state of the three states indicating that there is no duplicate address detected, a second state of the three states indicating that there is a duplicate address, and the third state of the three states indicating an unknown condition.