Title:
METHOD AND APPARATUS FOR DETERMINING LATENCY BETWEEN MULTIPLE SERVERS AND A CLIENT
Document Type and Number:
WIPO Patent Application WO2001076182
Kind Code:
A3
Abstract:
A method and apparatus for determining latency between multiple servers and a client receives requests for content server addresses from local domain names servers (LDNS). POPs that can serve the content are determined and sent latency metric requests. The content server receives the request for latency metrics and looks up the latency metric for the requesting client. Periodic latency probes are sent to the IP addresses in a Latency Management Table. The IP addresses of clients are masked so the latency probes are sent to higher level servers to reduce traffic across the network. The hop count and latency data in the packets sent in response to the latency probes are stored in the Latency Management Table and are used to determine the latency metric from the resident POP to the requesting client before sending the latency metric to the requesting server. The BGP hop count in the Latency Management Table is used for the latency metric upon the first request for an IP address. The latency metric is calculated for subsequent requests of IP addresses using the hop count and RTT data in the Latency Management Table. Latency metrics from POPs are collected and the inverse relationship of the hop counts in a weighted combination with the RTT are used to determine which latency metric indicates the optimal POP. The address of the optimal POP is then sent to the requesting LDNS.
Inventors:
IYER SHANKAR
LANKA SRIDHARA
LANKA SRIDHARA
Application Number:
PCT/US2001/010524
Publication Date:
November 06, 2003
Filing Date:
March 30, 2001
Export Citation:
Assignee:
SPEEDERA NETWORKS INC (US)
International Classes:
H04L12/24; H04L12/56; H04L29/06; H04L29/12; (IPC1-7): H04L29/06; H04L12/56
Other References:
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BHATTACHARJEE S ET AL: "APPLICATION-LAYER ANYCASTING", PROCEEDINGS OF THE IEEE INFOCOM '97. THE CONFERENCE ON COMPUTER COMMUNICATIONS. 16TH ANNUAL JOINT CONFERENCE OF THE IEEE COMPUTER AND COMMUNICATIONS SOCIETIES. DRIVING THE INFORMATION REVOLUTION. KOBE, APRIL 7 - 12, 1997, LOS ALAMITOS, CA: IEEE COMPU, vol. 3, 7 April 1997 (1997-04-07), pages 1388 - 1396, XP000851102, ISBN: 0-8186-7782-1
GUYTON J D ET AL: "LOCATING NEARBY COPIES OF REPLICATED INTERNET SERVERS", COMPUTER COMMUNICATIONS REVIEW, ASSOCIATION FOR COMPUTING MACHINERY. NEW YORK, US, vol. 25, no. 4, 1 October 1995 (1995-10-01), pages 288 - 298, XP000541664, ISSN: 0146-4833
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BHATTACHARJEE S ET AL: "APPLICATION-LAYER ANYCASTING", PROCEEDINGS OF THE IEEE INFOCOM '97. THE CONFERENCE ON COMPUTER COMMUNICATIONS. 16TH ANNUAL JOINT CONFERENCE OF THE IEEE COMPUTER AND COMMUNICATIONS SOCIETIES. DRIVING THE INFORMATION REVOLUTION. KOBE, APRIL 7 - 12, 1997, LOS ALAMITOS, CA: IEEE COMPU, vol. 3, 7 April 1997 (1997-04-07), pages 1388 - 1396, XP000851102, ISBN: 0-8186-7782-1
GUYTON J D ET AL: "LOCATING NEARBY COPIES OF REPLICATED INTERNET SERVERS", COMPUTER COMMUNICATIONS REVIEW, ASSOCIATION FOR COMPUTING MACHINERY. NEW YORK, US, vol. 25, no. 4, 1 October 1995 (1995-10-01), pages 288 - 298, XP000541664, ISSN: 0146-4833
FEI Z ET AL: "NOVEL SERVER SELECTION TECHNIQUE FOR IMPROVING THE RESPONSE TIME OFA REPLICATED SERVICE", PROCEEDINGS OF THE IEEE INFOCOM '98. THE CONFERENCE ON COMPUTER COMMUNICATIONS. 17TH ANNUAL JOINT CONFERENCE OF THE IEEE COMPUTER AND COMMUNICATIONS SOCIETY. GATEWAY TO THE 21ST CENTURY. SAN FRANCISCO, CA, MARCH 29 - APRIL 2, 1998, PROCEEDINGS IEEE I, vol. 2, 29 March 1998 (1998-03-29), pages 783 - 791, XP000852062, ISBN: 0-7803-4384-0
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