FAILOVER IN AN INTERNET LOCATION COORDINATE ENHANCED DOMAIN NAME SYSTEM

• US 20090222582A1
• Filed: 03/03/2008
• Published: 09/03/2009
• Est. Priority Date: 03/03/2008
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Josefsberg, Arne, Wolman, Alastair, Scheibel, Mark D., Dunagan, John D.
• Granted Patent: US 8,458,298 B2
• Time in Patent Office: Days
• US Class Current: 709/245
• CPC Class Codes: H04L 41/0654 using network fault recovery ring fault isolation or reconfiguration in loop networks without recovery actions by a network management system H04L12/437
• CPC Class Codes: H04L 41/0668 by dynamic selection of recovery network elements, e.g. replacement by the most appropriate element after failure
• CPC Class Codes: H04L 43/0811 by checking connectivity

Abstract

An exemplary failover module includes (a) instructions to respond to a connection problem to a host server at an IP address by selecting a different IP address from a cached list of IP addresses for a domain name associated with the host server and (b) instructions to return the selected, different IP address to future name queries where the instructions to respond, the instructions to initiate, and the instructions to return execute at an operating system level of a computing device configurable to connect to at least one of a plurality of host servers. Such a module may include instructions to optionally initiate a connection to a host server at the selected, different IP address. An exemplary failover module may optionally select an IP address based in part on Internet Location Coordinates (ILCs) where the host servers reside in an ILC enhanced Domain Name System (DNS). Other methods, devices and systems are also disclosed.

Claims

1. A failover module, implemented by a computing device, the failover module comprising:

instructions to respond to a connection problem to a host server at an IP address by selecting a different IP address from a cached list of IP addresses for a domain name associated with the host server; and

instructions to initiate a connection to a host server at the selected, different IP address;

wherein the instructions to respond and the instructions to initiate execute at an operating system level of a computing device configurable to connect to at least one of a plurality of host servers.

2. The failover module of claim 1 further comprising an application programming interface (API).

3. The failover module of claim 2 wherein the API comprises notification functionality to notify an application executing on the computing device of a failover.

4. The failover module of claim 1 wherein the connection problem to the host server at the IP address occurs in the context of a first application and the selected, different IP address is returned in the context of a second application.

5. The failover module of claim 1 wherein the connection problem comprises a connection failure.

6. The failover module of claim 1 wherein the connection problem comprises an unacceptable connection response time.

7. The failover module of claim 1 wherein the cached list comprises Internet Location Coordinates for at least some of the IP addresses.

8. The failover module of claim 7 wherein the selecting a different IP address comprising selecting the different IP address based at least in part on one or more of the Internet Location Coordinates.

9. The failover module of claim 1 wherein the host server comprises state information about an application executing on the computing device.

10. The failover module of claim 9 further comprising instructions to communicate state information to a host server.

11. A method for failover, implemented by a computing device, the method comprising:

requesting resolution of a domain name;

receiving a list of IP addresses for host servers associated with the domain name;

selecting the first IP address in the list;

recognizing a connection problem to the host server associated with the first IP address;

selecting the second IP address in the list; and

returning the second IP address to further DNS queries for the given domain name.

12. The method of claim 11 wherein the connection problem to the host server occurs in the context of a first application and the selected second IP address is returned in the context of a second application.

13. The method of claim 11 wherein the connection problem comprises a connection failure.

14. The method of claim 11 wherein the connection problem comprises an unacceptable connection response time.

15. The method of claim 11 wherein the requesting comprises an API call by an application seeking to establish a connection to a host server associated with the domain name.

16. The method of claim 15 wherein the application comprises a stateless application.

17. The method of claim 15 further comprising receiving state information from a stateful application.

18. The method of claim 17 further comprising communicating the state information to the host server at the second IP address.

19. A method for failover, implemented by a computing device, the method comprising:

requesting resolution of a domain name;

receiving a list of IP addresses and Internet Location Coordinates for host servers associated with the domain name;

selecting a best IP address from the list based at least in part on the Internet Location Coordinates;

recognizing a connection problem to the host server associated with the optimal IP address;

selecting a next best IP address from the list based at least in part on the Internet Location Coordinates; and

establishing a connection to the host server at the next best IP address.

20. The method of claim 19 further comprising receiving state information from a stateful application and communicating the state information to the host server at the next best IP address.