Distributed load-balancing internet servers

• US 6,578,066 B1
• Filed: 09/17/1999
• Issued: 06/10/2003
• Est. Priority Date: 09/17/1999
• Status: Expired due to Term

• Current Assignee: Radware Limited
• Original Assignee: Alteon Web Systems (Nortel Networks Corporation)
• Inventors: Logan, David B., Sathaye, Shirish
• Primary Examiner(s): Meky, Moustafa M.
• Assistant Examiner(s): Le, Hieu C.
• Application Number:
  US09/398,248
• Time in Patent Office: 1,362 Days
• Field of Search: 709/201-203, 709/105, 709/102, 709/223, 709/228, 712/27, 370/312
• US Class Current: 718/105
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/35 involving non-standard use of addresses for implementing network functionalities, e.g. coding subscription information within the address or functional addressing, i.e. assigning an address to a function
• CPC Class Codes: H04L 61/45 Network directories; Name-to-address mapping

Abstract

The actual site that serves the Web pages to a client in response to a URL domain name is automatically and transparently selected from a list of many switches each having identical data storage. In a peer hand-off process, a switch receives domain name server lookup request for a particular virtual Internet protocol (VIP) domain name. The switch examines the source IP-address for the domain name server request, examines the user'"'"'s IP-address, and determines if there is server site that is geographically close to that user. The switch examines an ordered hand-off table corresponding to the domain. The switch chooses a next remote server (or its own VIP) in line based on, (a) the remote server location compared to domain name server request source, (b) the remote servers'"'"' weights, and (c) the remote server that experienced the previous hand-off. The switch then sends the domain name server response back to client domain name server with the IP-addresses in an ordered list.

Claims

1. A distributed load-balancing Internet server system for providing web-based content and services to be redundantly delivered to many clients, comprising:

a domain name system (DNS) server for receiving a DNS-lookup request from a network user for a conversion of a particular uniform resource locator (URL) for a domain host name to a numeric Internet Protocol (IP) address, wherein said network user exists in a particular geographical area that can be discerned from a user Ip address;

a plurality of web-server sites that are geographically diverse and accessible to said network user, wherein each duplicates another in its web-based content and services that relate to said particular URL;

a policy manager that monitors the health and response performance of each of the plurality of web-server sites, and that maintains a list of such ones of the plurality of web-server sites according to their individual accessibility and geographic location; and

a DNS-query to IP-address converter connected to receive said DNS-lookup request from said network user, and connected to consult the policy manager for a preferred one of the plurality of web-server sites to respond to such DNS-lookup request, and further connected to provide said network user with an IP-address of said preferred one of the plurality of web-server sites;

wherein the policy manager further includes a response-time matrix and handoff table that maintains said list;

wherein;

the policy manager further includes a hand-off weight index that corresponds to a best-performing to a worst performing web-server site and a statistically configured weight that is multiplied by a relative positions in the ordered hand-off list of a server switch.

2. The system of claim 1, wherein:

each of the plurality of web-server sites corresponds to a virtual IP-address (VIP) and is physically located at a different place in the world.

3. The system of claim 1, wherein:

each of the plurality of web-server sites is able to off-load the others and operate in parallel to serve many simultaneous network users with diverse geographic locations.

4. The system of claim 1, wherein:

the DNS-query to IP-address converter operates such that lookup requests are balanced amongst each of the plurality of web-server sites.

5. The system of claim 1, wherein:

the policy manager further includes an Internet topology awareness and a distributed Server Load Balancing (SLB)-state protocol that is capable of exchanging health, load and throughput information between web-server sites either periodically, or when triggered by a predefined event.

6. The system of claim 1, wherein:

the plurality of web-server sites includes a main-content site that provides all web-content and services for duplication by each other web-server site.

7. A method of providing web-based content and services from to many clients from load-balanced redundant sites in response to a single DNS-lookup request, the method comprising the steps of:

receiving at a domain name system (DNS) server a DNS-lookup request from a network user for a conversion of a particular uniform resource locator (URL) for a domain host name to a numeric Internet Protocol (IP) address, wherein said network user exists in a particular geographical area that can be discerned from a user Ip-address;

placing a plurality of web-server sites at geographically diverse locations that are accessible to said network user, wherein each web-server site duplicates another in its web-based content and services that relate to said particular URL;

monitoring with a policy manager the health and response performance of each of the plurality of web-server sites, and maintaining a list of such ones of the plurality of web-server sites according to their individual accessibility and geographic location; and

converting a DNS-query to IP-address in response to a receipt of said DNS lookup request from said network user, and connecting to consult said policy manager for a preferred one of the plurality of web-server sites to respond to such DNS;

wherein;

the step of monitoring is such that said policy manager further includes a response time matrix and handoff table that maintains said list;

wherein;

the step of monitoring is such that said policy manager further includes a hand-off weight index that corresponds to a best-performing to a worst performing web-server site and a statistically configured weight that is multiplied by a relative positions in the ordered hand-off list of a server switch.

8. The method of claim 7, wherein:

the step of placing a plurality of web-server sites is such that each of said plurality of web-server sites corresponds to a virtual IP-address (VIP) and is physically located at a different place in the world.

9. The method of claim 7, wherein:

the step of placing a plurality of web-server sites is such that each of the plurality of web-server sites is able to off-load the others and operate in parallel to serve many simultaneous network users with diverse geographic locations.

10. The method of claim 7, wherein:

the step of converting is such that a DNS-query to IP-address converter operates such that lookup requests are balanced amongst each of said plurality of web-server sites.

11. The method of claim 9, wherein:

the step of monitoring is such that said policy manager further includes and Internet topology awareness and a distributed Server Load Balancing (SLB)-state protocol that is capable of exchanging health, load and throughput information between web-server sites either periodically, or when triggered by a predefined event.

12. The method of claim 7, wherein:

the step of placing is such that said plurality of web-server sites includes a main-content site that provides all web-content and services for duplication by each other web-server site.