Multipath routing process

• US 8,706,906 B2
• Filed: 03/08/2012
• Issued: 04/22/2014
• Est. Priority Date: 10/25/2005
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Hoynowski, Charles, Hirschberg, Daniel
• Primary Examiner(s): THIAW, CATHERINE B
• Application Number:
  US13/415,518
• Publication Number:
  US 20120166639A1
• Time in Patent Office: 775 Days
• Field of Search: 709/203, 709223-225, 709238-240
• US Class Current: 709/238
• CPC Class Codes: G06F 11/1443 Transmit or communication errors
• CPC Class Codes: G06F 11/2023 Failover techniques
• CPC Class Codes: G06F 11/2048 where the redundant components share neither address space nor persistent storage
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/20 Hop count for routing purposes, e.g. TTL
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/247 using M:N active or standby paths
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/101 based on network conditions

Abstract

Methods and apparatus that enable more than one server to host a resource using a shared IP address such that a client may generally access the resource on any of the servers using the shared IP address are disclosed. According to one aspect of the present invention, a method for providing paths that allow a client to access a resource in a TCP/IP network includes obtaining an IP address, as well as associating the IP address to first and second servers. The first and second servers support the resource at the IP address, and a first path of the plurality of paths that allow the client to access the resource is between the client and the first server and a second path of the plurality of paths that allow the client to access the resource is between the client and the second server.

Claims

1. A method of providing access to a resource, the resource being associated with a domain name, the method comprising:

identifying from among a plurality of web servers between which packets are routed via a gateway protocol, a first web server in a first autonomous system for use in establishing a session to access the resource at an IP address at which the resource is also hosted in a second autonomous system by a second web server in the plurality of web servers, at least based on determining whether the first web server allows the resource to be accessed, by one or more processors checking whether links and nodes to the first web server are functional;

wherein the first autonomous system comprises a first IP address list that includes at least said IP address, said IP address being associated in the first autonomous system with the first web server, the first web server being the only web server which is active at any given time at said IP address in the first autonomous system; and

wherein the second autonomous system comprises a second IP address list that includes at least said IP address, said IP address being associated in the second autonomous system with the second web server.

2. The method of claim 1 further comprising:

receiving a request to access the resource prior to said identifying.

3. The method of claim 1 wherein:

the domain name is associated with the IP address.

4. The method of claim 1 further comprising, prior to said identifying:

determining that a first path between a client and the first web server has a lower cost than a second path between the client and the second web server.

5. The method of claim 1 further comprising, prior to said identifying:

determining at least a first distance associated with a first path between a client and the first web server and a second distance associated with a second path between the client and the second web server, and determining that the first path is shorter than the second path.

6. The method of claim 1 further comprising, prior to said identifying:

determining that a first path between a client and the first web server is active and a second path between the client and the second web server is inactive.

7. The method of claim 1 further comprising, prior to said identifying:

determining that the first web server has a lighter load than the second web server.

8. The method of claim 1 further comprising:

calculating a first cost value for a first path between a client and the first web server;

calculating a second cost value for a second path between the client and the second web server;

when the first cost value is less than the second cost value, selecting the first path as a lowest cost path and the second path as an alternative path;

when the second cost value is less than the first cost value, selecting the second path as the lowest cost path and the first path as the alternative path;

determining whether the lowest cost path has available bandwidth to connect to the client; and

when the lowest cost path is operational and does not have available bandwidth, not permitting the client to access the resource via the lowest cost path.

9. The method of claim 8 further comprising:

when not permitting the client to access the resource via the lowest cost path, allowing the client to access the resource via the alternative path.

10. The method of claim 1 wherein the links and nodes to the first web server are in a first path thereto, and the method further comprises:

when a node failure or a link failure is identified in the first path, a second path is used to access the resource in the second autonomous system without requiring that IP address change propagation occur.

21. The method of claim 1 further comprising:

checking whether the links and nodes to the first web server are functional subsequent to establishment of the session.

11. One or more non-transitory computer-readable media for providing access to a resource, the resource being associated with a domain name, the one or more non-transitory computer-readable media comprising instructions that when executed in one or more computers cause the one or more computers to:

identify from among a plurality of web servers between which packets are routed via a gateway protocol, a first web server in a first autonomous system for use in establishing a session to access the resource at an IP address at which the resource is also hosted in a second autonomous system by a second web server in the plurality of web servers, at least based on determining whether the first web server allows the resource to be accessed, by one or more processors checking whether links and nodes to the first web server are functional;

wherein the first autonomous system comprises a first IP address list that includes at least said IP address, said IP address being associated in the first autonomous system with the first web server, the first web server being the only web server which is active at any (liven time at said IP address in the first autonomous system;

wherein the second autonomous system comprises a second IP address list that includes at least said IP address, said IP address being associated in the second autonomous system with the second web server.

12. The one or more non-transitory computer-readable media of claim 11 further comprising instructions to cause the one or more computers to:

receive a request to access the resource prior to said identifying.

13. The one or more non-transitory computer-readable media of claim 11 wherein:

the domain name is associated with the IP address.

14. The one or more non-transitory computer-readable media of claim 11 further comprising instructions to cause the one or more computers to, prior to executing said instructions to identify:

determine that a first path between a client and the first server has a lower cost than a second path between the client and the second server.

15. The one or more non-transitory computer-readable media of claim 11 further comprising instructions to cause the one or more computers to, prior to executing said instructions to identify:

determine at least a first distance associated with a first path between a client and the first server and a second distance associated with a second path between the client and a second server, and determining that the first path is shorter than the second path.

16. The one or more non-transitory computer-readable media of claim 11 further comprising instructions to cause the one or more computers to, prior to executing said instructions to identify:

determine that a first path between a client and the first server is active and a second path between the client and the second server is inactive.

17. The one or more non-transitory computer-readable media of claim 11 further comprising instructions to cause the one or more computers to, prior to executing said instructions to identify:

determine that the first server has a lighter load than the second server.

18. The one or more non-transitory computer-readable media of claim 11 further comprising instructions to cause the one or more computers to:

calculate a first cost value for a first path between a client and the first server;

calculate a second cost value for a second path between the client and the second server;

when the first cost value is less than the second cost value, select the first path as a lowest cost path and the second path as an alternative path;

when the second cost value is less than the first cost value, select the second path as the lowest cost path and the first path as the alternative path;

determine whether the lowest cost path has available bandwidth to connect to the client; and

when the lowest cost path is operational and does not have available bandwidth, not permit the client to access the resource via the lowest cost path.

19. The one or more non-transitory computer-readable media of claim 11 wherein the links and nodes to the first web server are in a first path thereto, and wherein:

when a node failure or a link failure is identified in the first path, a second path is used to access the resource in the second autonomous system without requiring that IP address change propagation occur.

22. The one or more non-transitory computer-readable media of claim 11 further comprising instructions to:

check whether the links and nodes to the first web server are functional subsequent to establishment of the session.

20. A system for providing access to a resource, the system comprising:

means for identifying from among a plurality of web servers between which packets are routed via a gateway protocol, a first web server in a first autonomous system for use in establishing a session to access the resource at an IP address at which the resource is also hosted in a second autonomous system by a second web server in the plurality of web servers, at least based on determining whether the first web server allows the resource to be accessed, by one or more processors checking whether links and nodes to the first web server are functional;

wherein the first autonomous system comprises a first IP address list that includes at least said IP address, said IP address being associated in the first autonomous system with the first web server, the first web server being the only web server which is active at any given time at said IP address in the first autonomous system; and

wherein the second autonomous system comprises a second IP address list that includes at least said IP address, said IP address being associated in the second autonomous system with the second web server.