US 6363056

Patent Overview — US6363056B1

Title: Low overhead continuous monitoring of network performance

Patent number: US6363056B1
Application number: US09/115,438
Inventors: Mandis Sadr Mohammad Beigi; Raymond Byars Jennings; Dinesh Chandra Verma
Original assignee / current assignee (as listed): International Business Machines Corp (IBM)
Priority date: 1998-07-15
Filing date: 1998-07-15
Publication/grant date: 2002-03-26
Legal status (as listed): Expired – Fee Related; anticipated expiration 2018-07-15

Purpose. The patent addresses monitoring network performance metrics between access points in a provider or intranet backbone. A network operator typically controls intermediate access points—not traffic sources or destinations—and a large ISP or corporate backbone has many endpoints, so continuous monitoring across all pair-wise access points is uncommon. Traditional heavyweight probes across all access points are described as not viable because of the added network load. The patent seeks low-overhead continuous monitoring enabling bandwidth monitoring, performance monitoring, and fault monitoring.

Plain-language scope. Network probe packets are generated by copying normal outbound packets and modifying them while keeping the destination address intact. Probe packets are generated when a packet count reaches a specified value N—for example, copying every Nth packet, changing the source address to that of the originating access router, changing the protocol number to a reserved value, attaching a UDP header with a reserved pattern, and attaching a UDP payload containing a probe number and local time-stamp. Recipient nodes identify probes by protocol number and UDP header pattern; nodes unaware of the format discard them through normal network mechanisms. A trigger mechanism determines when to generate a probe; a probe generation mechanism builds it from data-packet contents; a probe detection mechanism at the second access point detects it; and an analysis mechanism compares detected probes to generated ones. Delay can be determined using a common clock; bandwidth via counting probes received versus expected.

Source: https://patents.google.com/patent/[US6363056](/patent/US6363056)/en

What the excerpt does not establish. It does not provide the full claims, complete specification, cited prior art, prosecution history, or claim-construction findings; it does not verify assignee accuracy, legal status, or expiration. No litigation, ownership-transfer, validity, or prior-art analysis is included.