APPLICATION DELIVERY CONTROLLER AND GLOBAL SERVER LOAD BALANCER

• US 20140258536A1
• Filed: 03/08/2013
• Published: 09/11/2014
• Est. Priority Date: 03/08/2013
• Status: Active Grant

• Current Assignee: A10 Networks Incorporated
• Original Assignee: A10 Networks Incorporated
• Inventors: Chiong, John
• Granted Patent: US 9,900,252 B2
• Time in Patent Office: Days
• US Class Current: 709/226
• CPC Class Codes: H04L 47/125 by balancing the load, e.g. traffic engineering
• CPC Class Codes: H04L 47/28 in relation to timing considerations

Abstract

Application Delivery Controller (ADC), Global Server Load Balancer (GSLB), and methods for their operation in data networks are disclosed. The methods for load balancing may include receiving a query concerning a host name from a client, determining that there are two or more host servers associated with the host name, measuring various metrics associated with each of the two or more host servers and a local Domain Name Server (DNS), and based at least in part on the measurement, selecting a host server among the two or more host servers. The load balancing may also be based on a measured round trip time.

Claims

1. A method for load balancing among host servers of a data network, the method comprising:

receiving, via a GSLB, a domain name query from a client or a DNS;

retrieving, via the GSLB, a plurality of network addresses associated with the domain name query;

retrieving, via the GSLB, multiple performance metrics for each network address;

randomly selecting, via the GSLB, one of the network addresses;

calculating a score associated with the multiple performance metrics related to the selected network address;

determining, via the GSLB, that the score for the randomly selected network address meets a predetermined threshold; and

based on the determination, returning, via the GSLB, the randomly selected network address to the client or the DNS.

2. The method of claim 1, further comprising:

measuring, via the GSLB, multiple performance metrics associated with a plurality of switches, wherein each switch is associated with one or more host servers;

determining, via the GSLB, a plurality of network addresses associated with the one or more host servers; and

storing, via the GSLB, the multiple performance metrics in association with the plurality of network addresses in a table.

3. The method of claim 2, further comprising:

determining, via the GSLB, that the score for the randomly selected network address does not meet the predetermined threshold; and

randomly selecting, via the GSLB, one of the remaining network addresses from the table.

4. The method of claim 2, further comprising:

determining, via the GSLB, that the scores for all network addresses do not meet the predetermined threshold; and

decreasing, via the GSLB, the predetermined threshold.

5. The method of claim 1, wherein all of the steps are performed sequentially for at least two cycles to randomly select at least two network addresses so that at least two randomly selected network addresses are returned to the client or the DNS.

6. The method of claim 1, wherein the randomly selected network address is stored in memory.

7. The method of claim 6, further comprising:

receiving a recognized domain name query;

repeating at least once the steps leading to a randomly selected network address to generate at least one new randomly selected network address; and

returning both the at least one new randomly selected network address and the stored network address to the client or the DNS.

8. The method of claim 1, wherein the predetermined threshold is selected from a plurality of predetermined thresholds associated with a plurality of domain names.

9. The method of claim 1, wherein the multiple performance metrics includes a plurality of round trip times from a plurality of switches associated with one or more host servers and a LDNS associated with the client.

10. The method of claim 1, wherein the multiple performance metrics include one or more of the following:

application health metrics, proximity metrics, and weighted preferences metrics.

11. A method for load balancing among host servers of a data network, the method comprising:

receiving, via a global server load balancer (GSLB), a query concerning a host name from a client;

determining, via the GSLB, that there are two or more site switches and host servers associated with the host name;

measuring, via the GSLB, round trip times associated with each of the two or more site switches and a Local Domain Name Server (DNS) assigned to the client; and

selecting based at least in part on the measuring, via the GSLB, a selected host server from the two or more host servers.

12. The method of claim 11, further comprising providing a network address of the selected host server to the DNS.

13. The method of claim 11, wherein the round trip time is a time for exchange of at least one message from one or more switches associated with the two or more host servers and the DNS.

14. The method of claim 11, wherein the round trip time is a time for exchange of at least one message from each of the two or more host servers and the DNS.

15. The method of claim 11, further comprising transmitting data from the selected host server to the client.

16. The method of claim 11, further comprising:

storing the round trip times associated with the two or more host servers in a GSLB;

retrieving, via the GSLB, at least one of the round trip times in response to a further query.

17. The method of claim 11, wherein the query concerning the host name is generated by an ADC associated with the one or more host servers.

18. The method of claim 11, further comprising selecting a host server, the selected server being associated with the shortest round trip time.

19. The method of claim 11, wherein all of the steps are performed sequentially for at least two cycles to randomly select at least two network addresses so that at least two randomly selected network addresses are returned to the client or the DNS.

20. The method of claim 11, wherein the randomly selected network address is stored in memory.

21. The method of claim 11, further comprising:

receiving a recognized domain name query;

repeating at least once the steps leading to a randomly selected network address to generate at least one new randomly selected network address; and

returning both the at least one new randomly selected network address and the stored network address to the client or the DNS.