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:
Jan. 30, 2001
Filed:
Nov. 25, 1996
Tatsuya Nagata, Nagoya, JP;
Kazuhiro Ozawa, Nagoya, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
In an ATM switch, after a communication path is properly set up, a continuity test is performed by passing an OAM cell through the communication path before initiating the transmission of user cells. After the transmission of user cells is initiated, a loopback test is performed by periodically inserting an OAM cell in a user cell flow. When a fault condition is detected as a result of the OAM cell loopback test, a peak cell rate environment is created by adding OAM cells to the user cells for a limited period of time, and communication quality is measured under the thus created environment. When a point-to-multipoint connection with a plurality of leaf points is set up, correspondence between each leaf point and a physical connection point is recorded in a table. When a loopback test to a specific leaf point is requested from a maintenance console, an ATM line control unit corresponding to the specific leaf point is determined by referring to the table, and transmission of the OAM cell is allowed only through that ATM line control unit. In this way, an OAM cell loopback test to a specific leaf point can be accomplished.