Stephanie L Quarles

US Patent:

59960019, Nov 30, 1999

Filed:

Feb 10, 1997

Appl. No.:

8/799644

Inventors:

Philip Quarles - Northport NY
Stephanie Quarles - Northport NY

International Classification:

G06F 944

US Classification:

709203

Abstract:

A high availability on-line transaction processing (OLTP) system utilizes both hardware and software. Geographically separated primary (live) and backup (shadow) communications servers link live and shadow OLTP systems to geographically separated live and shadow Wide Area Networks and remote client computers. The remote client computers communicate with the live and shadow OLTP systems through their respective live and shadow WANs and communications servers. The live OLTP system sends "keep-alive" messages to the shadow system via the dedicated circuits on a frequent basis. If the shadow OLTP system does not receive a keep-alive message from the live system within a designated time interval, it sends "probe messages" to the live communications servers and live OLTP system, via the shadow WAN, client computers and live WAN to determine their status. If the live communications servers respond to the probe message(s) but the live OLTP system does not, the shadow OLTP system deduces that the live OLTP system failed and automatically takes over the role of the live system without operator intervention.