GLOBAL SERVER LOAD BALANCING

• US 20100293296A1
• Filed: 11/17/2008
• Published: 11/18/2010
• Est. Priority Date: 09/26/2000
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Foundry Networks Incorporated (Broadcom, Inc.)
• Inventors: Cheung, David Chun Ying, Hsu, Ivy Pei-Shan, Jalan, Rajkumar Ramniranjan
• Granted Patent: US 9,225,775 B2
• Time in Patent Office: Days
• US Class Current: 709/245
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/1012 based on compliance of requirements or conditions with available server resources
• CPC Class Codes: H04L 67/1021 based on client or server locations

Abstract

A global server load balancing (GSLB) switch serves as a proxy to an authoritative DNS communicates with numerous site switches which are coupled to host servers serving specific applications. The GSLB switch receives from site switches operational information regarding host servers within the site switches neighborhood. When a client program requests a resolution of a host name, the GSLB switch, acting as a proxy of an authoritative DNS, returns one or more ordered IP addresses for the host name. The IP addresses are ordered using metrics that include the information collected from the site switches. In one instance, the GSLB switch places the address that is deemed “best” at the top of the list.

Claims

1-26. -26. (canceled)

27. A method performed by a load balancing switch, the method comprising:

storing, by the load balancing switch, round trip time data for each of a plurality of site switches, wherein the round trip time data for a site switch in the plurality of site switches comprises a time for exchanging at least one message between the site switch and a client machine, each site switch associated with one or more host servers;

storing, by the load balancing switch, a plurality of network addresses generated in response to a domain name query, the plurality of network addresses comprising network addresses of multiple site switches from the plurality of site switches; and

ordering, by the load balancing switch, the plurality of network addresses based upon the round trip time data for the plurality of site switches to generate a first ordered list of network addresses.

28. The method of claim 27 wherein, for a first site switch in the plurality of site switches, the round trip time data for the first site switch comprises time information for exchanging at least one message between the first site switch and the client machine.

29. The method of claim 28 wherein the time information for exchanging at least one message between the first site switch and the client machine comprises information indicating a time interval between a time when the first site switch receives a connection request from the client machine and a time when the first site switch receives a connection acknowledgement from the client machine in response to an acknowledgment packet sent from the first site switch to the client machine in response to receiving the connection request.

30. The method of claim 27 further comprising reordering, by the load balancing switch, the first ordered list based upon a set of performance metrics associated with the plurality of site switches other than the round trip time data to generate a second ordered list.

31. The method of claim 30 wherein the set of performance metrics comprises geographical locations of the host servers associated with the plurality of site switches.

32. The method of claim 27 wherein storing the round trip time data for each of a plurality of site switches comprises storing the round trip time data for the plurality of site switches in a table indexed by network neighborhood.

33. The method of claim 27 wherein each site switch in the plurality of site switches acts as a proxy for the one or more host servers associated with the site switch.

34. The method of claim 27 further comprising periodically receiving, by the load balancing switch, the round trip time data for each of the plurality of site switches from the site switch, wherein the round trip time data received from a site switch comprises round trip time data collected by the site switch for each connection established between the site switch and the client machine.

35. A system comprising:

a load balancing switch configured to store round trip time data for each of a plurality of site switches, wherein the round trip time data for a site switch in the plurality of site switches comprises a time for exchanging at least one message between the site switch and a client machine, each site switch associated with one or more host servers;

wherein the load balancing switch is configured to

store a plurality of network addresses generated in response to a domain name query, the plurality of network addresses comprising network addresses of multiple site switches from the plurality of site switches, and

order the plurality of network addresses based upon the round trip time data for the plurality of site switches to generate a first ordered list of network addresses.

36. The system of claim 35 wherein, for a first site switch in the plurality of site switches, the round trip time data for the first site switch comprises time information for exchanging at least one message between the first site switch and the client machine.

37. The system of claim 36 wherein the time information for exchanging at least one message between the first site switch and the client machine comprises information indicating a time interval between a time when the first site switch receives a connection request from the client machine and a time when the first site switch receives a connection acknowledgement from the client machine in response to an acknowledgment packet sent from the first site switch to the client machine in response to receiving the connection request.

38. The system of claim 35 wherein the load balancing switch is configured to reorder the first ordered list based upon a set of performance metrics associated with the plurality of site switches other than the round trip time data to generate a second ordered list.

39. The system of claim 38 wherein the set of performance metrics comprises geographical locations of the host servers associated with the plurality of site switches.

40. The system of claim 35 wherein the load balancing switch is configured to store the round trip time data for the plurality of site switches in a table indexed by network neighborhood.

41. The system of claim 35 wherein each site switch in the plurality of site switches acts as a proxy for the one or more host servers associated with the site switch.

42. The system of claim 35 wherein the load balancing switch is further configured to periodically receive the round trip time data for each of the plurality of site switches from the site switch, wherein the round trip time data received from a site switch comprises round trip time data collected by the site switch for each connection established between the site switch and the client machine.

43. A switch comprising:

a memory configured to store round trip time data for each of a plurality of network devices, wherein the round trip time data for a network device comprises a time associated with communication between the network device and a client machine; and

a module configured to generate an ordered list of network addresses based upon the round trip time data for the plurality of network devices, the ordered list of network addresses comprising network addresses generated in response to a domain name query.

44. The switch of claim 43 wherein, for a first network device in the plurality of network devices, the time associated with communication between the first network device and the client machine specifies a time interval between a time when the first network device receives a connection request from the client machine and a time when the first network device receives a connection acknowledgement from the client machine in response to an acknowledgment packet sent from the first network device to the client machine in response to receiving the connection request.

45. The switch of claim 43 wherein the module is configured to reorder the first ordered list based upon a set of performance metrics associated with the plurality of network devices other than the round trip time data to generate a second ordered list.

46. The switch of claim 45 wherein the set of performance metrics comprises geographical locations of one or more host servers associated with the plurality of network devices.

47. The switch of claim 43 wherein the memory is configured to store a table comprising the round trip time data for the plurality of network devices, wherein the table is indexed by network neighborhood.

48. The switch of claim 43 wherein each network device in the plurality of network devices acts as a proxy for one or more host servers associated with the network device.

49. A switch comprising:

a memory configured to store a round trip time for each of a plurality of network devices, wherein the round trip time for each network device identifies a time associated with communication between the network device and a client machine; and

a module configured to, in response to a domain name query,

determine a lowest round trip time from among the stored round trip times, and

determine a network address associated with the network device with the lowest round trip time.