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:
May. 02, 2000
Filed:
Nov. 06, 1998
R Scott Drysdale, Frederick, MD (US);
James D Ennis, Jr, Ijamsville, MD (US);
John E Hasselkus, Germantown, MD (US);
Thomas R Nisbet, Ellicot City, MD (US);
Robert C Troutman, Gaithersburg, MD (US);
Kenneth J Rehbehn, Garret Park, MD (US);
David E Wheeler, Jr, Germantown, MD (US);
Visual Networks Technologies, Inc., Rockville, MD (US);
Abstract
A data transmission system includes probes connected between end user sites and a data switching network. Each probe is connected to the switching network via an access channel wherein transmission circuits establish paths between the sites through the access channel and switching network. The probes capture and retransmit data traveling between the sites over respective transmission circuits, and can thereby insert service level analysis (SLA) messages into the data traffic in order to actively communicate network performance information to other probes. For each transmission circuit, the probes periodically collect measurements related to one or more network performance metrics, including: round-trip delay (RTD), data delivery ratio (DDR) and network availability. During each SLA measurement cycle, a sequence of SLA messages is exchanged over each transmission circuit, which messages contain data used to determine RTD and DDR. Optionally, the SLA message contents and protocol are designed to allow the SLA messages to be encapsulated in a single, standard data unit of any conventional data transmission protocol, such as an ATM cell. Consequently, the messaging system can be used with any data transmission protocol and in interworked networks without modification of the message data payload. The SLA measurements collected by the probes can be transmitted to a console in communication with the probes for processing, display, and archiving.