Network load balancing with session information

• US 20040268357A1
• Filed: 06/30/2003
• Published: 12/30/2004
• Est. Priority Date: 06/30/2003
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Joy, Joseph M., Sivathanup, Karthic Nadarajapillai
• Granted Patent: US 7,613,822 B2
• Time in Patent Office: Days
• US Class Current: 718/105
• 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 67/1029 using data related to the state of servers by a load balancer
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 67/63 Routing a service request depending on the request content or context
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

In a first exemplary implementation, one or more processor-accessible media include processor-executable instructions that, when executed, direct a system to perform actions including: receiving host status information from multiple hosts; and making load balancing decisions responsive to the received host status information. In a second exemplary implementation, a system includes: session tracking infrastructure that is adapted to acquire session information; and load balancing infrastructure that is adapted to utilize the session information when routing connection requests to multiple hosts. In a third exemplary implementation, one or more processor-accessible media include processor-executable instructions that, when executed, direct a system to perform actions including: acquiring session information for multiple session contexts from one or more applications that established the multiple session contexts; and routing network traffic to the one or more applications responsive to the acquired session information.

Claims

1. One or more processor-accessible media comprising processor-executable instructions that, when executed, direct a system to perform actions comprising:

receiving host status information from a plurality of hosts; and

making load balancing decisions responsive to the received host status information.

2. The one or more processor-accessible media as recited in claim 1, comprising the processor-executable instructions that, when executed, direct the system to perform a further action comprising:

receiving from a client a connection request having a session reference; and

wherein the action of making comprises an action of;

selecting a destination target for the connection request responsive to the received host status information and based on the session reference.

3. The one or more processor-accessible media as recited in claim 1, wherein the host status information comprises session information that is associated with the plurality of hosts, and the action of receiving comprises an action of:

receiving the session information from the plurality of hosts.

4. The one or more processor-accessible media as recited in claim 1, wherein the host status information comprises connection-context-specific host status information, and the action of making comprises an action of:

making load balancing decisions responsive to the connection-context-specific host status information.

5. The one or more processor-accessible media as recited in claim 1, wherein the action of receiving comprises at least one action of:

receiving the host status information directly from one or more hosts of the plurality of hosts; and

receiving the host status information indirectly from one or more hosts of the plurality of hosts.

6. A method for network load balancing, the method comprising:

determining session information at a plurality of hosts;

sending the session information from the plurality of hosts to at least one device comprising load balancing infrastructure;

receiving the session information from the plurality of hosts at the at least one device; and

making load balancing decisions with the load balancing infrastructure responsive to the received session information.

7. The method as recited in claim 6, wherein the determining comprises:

determining the session information in conjunction with one or more applications that establish sessions, the one or more applications resident at and executing on the plurality of hosts.

8. One or more processor-accessible media comprising processor-executable instructions that, when executed, direct a system to perform actions comprising:

acquiring host status information at a plurality of hosts; and

sending the acquired host status information from the plurality of hosts.

9. The one or more processor-accessible media as recited in claim 8, wherein the host status information comprises session information that is associated with the plurality of hosts and the action of sending comprises an action of:

sending the session information from the plurality of hosts.

10. The one or more processor-accessible media as recited in claim 8, wherein the action of acquiring comprises an action of:

acquiring the host status information with regard to sessions opened by applications that are executing on the plurality of hosts.

11. The one or more processor-accessible media as recited in claim 8, wherein the action of sending comprises an action of:

sending the acquired host status information from the plurality of hosts to load balancing functionality.

21. The one or more processor-accessible media as recited in claim 20, 11 wherein a format of the session up message comprises at least a session identifier and a host identifier.

22. The one or more processor-accessible media as recited in claim 21, wherein the session identifier comprises an alphanumeric string, and the host identifier comprises binary bits.

12. A system comprising:

session tracking infrastructure at a host, the session tracking infrastructure adapted to accept notifications regarding session establishments and session terminations, the session tracking infrastructure capable of sending messages indicating that sessions are going up and that sessions are going down to load balancing infrastructure.

13. The system as recited in claim 12, wherein the system further comprises:

one or more applications that are adapted to provide the notifications regarding session establishments and session terminations to the session tracking infrastructure.

14. The system as recited in claim 12, wherein the system further comprises:

a device on which the host is resident.

15. The system as recited in claim 14, wherein the system further comprises:

another device on which the load balancing infrastructure is resident.

16. The system as recited in claim 12, wherein the system further comprises:

another session tracking infrastructure at another host, the other session tracking infrastructure adapted to accept notifications regarding session establishments and session terminations, the other session tracking infrastructure capable of sending messages indicating that sessions are going up and that sessions are going down to the load balancing infrastructure;

wherein the system comprises a first device on which the host is resident and a second device on which the other host is resident.

17. One or more processor-accessible media comprising processor-executable instructions that, when executed, enable a system to implement a communications protocol between at least one host and one or more load balancing units, the communications protocol usable for communicating session information between the at least one host and the one or more load balancing units.

18. The one or more processor-accessible media as recited in claim 17, wherein at least a portion of the processor-executable instructions comprise software that is adapted to be executed on the at least one host.

19. The one or more processor-accessible media as recited in claim 17, wherein at least a portion of the processor-executable instructions comprise software that is adapted to be executed on the one or more load balancing units.

20. The one or more processor-accessible media as recited in claim 17, comprising the processor-executable instructions that, when executed, enable the system to implement the communications protocol that includes at least one message, the at least one message comprising a session up message.

23. The one or more processor-accessible media as recited in claim 17, comprising the processor-executable instructions that, when executed, enable the system to implement the communications protocol that includes at least one message, the at least one message comprising a session down message.

24. The one or more processor-accessible media as recited in claim 23, wherein a format of the session down message comprises at least a session identifier for a session that has been closed.

25. The one or more processor-accessible media as recited in claim 17, wherein each respective load balancing unit of the one or more load balancing units comprises a respective device of a plurality of devices.

26. A system comprising:

at least one device that comprises load balancing functionality, the at least one device having a table that includes a plurality of session information entries, each session information entry of the plurality of session information entries associated with a session context;

each session information entry of the plurality of session information entries comprising;

a key that identifies the associated session context; and

data that identifies a host at which the associated session context is open, the data received from the host.

27. The system as recited in claim 26, wherein the data comprises a network address that identifies the host.

28. The system as recited in claim 27, wherein the network address comprises at least one of (i) a virtual internet protocol (IP) address and port and (ii) a physical IP address and port.

29. The system as recited in claim 26, wherein the key varies in dependence on a type of session of the associated session context.

30. The system as recited in claim 29, wherein the type of session may comprise at least one of a transmission control protocol (TCP) session, a transport layer security (TLS) and/or a secure sockets layer (SSL) session, a point-to-point tunneling protocol (PPTP) session, a secure internet protocol (IPSec) and/or a layer-2 tunneling protocol (L2TP) session, a hyper text transfer protocol (HTTP) cookie-based session, a Terminal Server session, and an administrator-defined session.

31. The system as recited in claim 26, wherein each session information entry of the plurality of session information entries further comprises:

metadata that can be used (i) to resolve collisions between session information entries for a single session context and (ii) to track session information entry aliveness.

32. The system as recited in claim 26, further comprising:

a session affinity preserver that is adapted to utilize the table that includes the plurality of session information entries to preserve session affinity for connections with clients.

33. The system as recited in claim 32, wherein the session affinity preserver is further adapted to route incoming connection requests having session references to hosts affinitized thereto by comparing the session references to the keys of the plurality of session information entries.

34. The system as recited in claim 26, wherein the system further comprises:

a plurality of devices, with each respective device of the plurality of devices including a respective table of a plurality of tables; and

wherein each respective table of the plurality of tables includes a plurality of session information entries.

35. One or more processor-accessible media comprising processor-executable instructions that, when executed, direct a system to build a session table, the session table including a plurality of entries, each entry of the plurality of entries associated with a session context;

each entry of the plurality of entries comprising;

a session identifier that identifies the associated session context; and

a session type indicator that indicates a session type of the associated session context;

wherein the session identifier and the session type indicator are accepted from an application that establishes the associated session context.

36. The one or more processor-accessible media as recited in claim 35, wherein the session identifier and the session type indicator are accepted from the application that establishes the associated session context in accordance with an application programming interface (API).

37. The one or more processor-accessible media as recited in claim 35, comprising the processor-executable instructions that, when executed, direct the system to insert entries into the session table responsive to acceptance of session establishment notifications from the application.

38. The one or more processor-accessible media as recited in claim 35, comprising the processor-executable instructions that, when executed, direct the system to remove entries from the session table responsive to acceptance of session termination notifications from the application.

39. One or more processor-accessible media comprising processor-executable instructions that comprise at least part of an application, wherein the processor-executable instructions, when executed, enable the application to implement an application programming interface (API) between the application and load balancing infrastructure;

the API including;

a session establishment notification provided by the application and accepted at the load balancing infrastructure; and

a session termination notification provided by the application and accepted at the load balancing infrastructure.

40. The one or more processor-accessible media as recited in claim 39, wherein the load balancing infrastructure comprises session tracking infrastructure.

41. The one or more processor-accessible media as recited in claim 39, wherein the application is capable of being hosted on at least one device.

42. The one or more processor-accessible media as recited in claim 39, wherein the application is capable of being hosted on at least one device;

and wherein the load balancing infrastructure comprises session tracking infrastructure that is capable of being resident at and executing on the at least one device.

43. The one or more processor-accessible media as recited in claim 39, wherein the session establishment notification includes a session identifier.

44. The one or more processor-accessible media as recited in claim 43, wherein the session termination notification includes the session identifier.

45. The one or more processor-accessible media as recited in claim 39, wherein the session establishment notification includes a session identifier and at least one of an identifier of the application and an identifier of a session type.

46. A system comprising:

load balancing infrastructure that is adapted to implement an application programming interface (API) between one or more applications and the load balancing infrastructure, the API enabling the load balancing infrastructure to accept session information from the one or more applications.

47. The system as recited in claim 46, wherein the load balancing infrastructure comprises session tracking infrastructure.

48. The system as recited in claim 47, further comprising:

at least one device on which the session tracking infrastructure is resident, the at least one device hosting the one or more applications.

49. The system as recited in claim 46, wherein the API further enables the load balancing infrastructure to accept session information from the one or more applications via notifications of session establishment and session termination.

50. The system as recited in claim 46, wherein the load balancing infrastructure is further adapted to route incoming traffic connections responsive to the accepted session information.

51. A system comprising:

session tracking infrastructure that is adapted to acquire session information; and

load balancing infrastructure that is adapted to utilize the session information when routing connection requests to a plurality of hosts.

52. The system as recited in claim 51, wherein the session tracking infrastructure comprises a session table that stores at least a portion of the acquired session information.

53. The system as recited in claim 51, wherein the session tracking infrastructure comprises a session table that stores at least a portion of the acquired session information;

the session table including a plurality of entries, each entry of the plurality of entries associated with a particular session context of a plurality of session contexts.

54. The system as recited in claim 51, wherein the session tracking infrastructure comprises a session table that stores at least a portion of the acquired session information;

the session table including a plurality of entries, each entry of the plurality of entries including a session identifier.

55. The system as recited in claim 51, wherein the session tracking infrastructure is further adapted to accept session establishment notifications and session termination notifications from one or more applications in order to acquire the session information.

56. The system as recited in claim 51, wherein the session tracking infrastructure is further adapted to send session up messages and session down messages to the load balancing infrastructure.

57. The system as recited in claim 51, wherein the session tracking infrastructure comprises a session table that stores at least a portion of the acquired session information, the session table including a plurality of entries;

and

wherein the session tracking infrastructure is further adapted to insert entries into the session table and to remove entries from the session table as sessions are opened and closed, respectively.

58. The system as recited in claim 51, wherein the session tracking infrastructure comprises a session table that stores at least a portion of the acquired session information, the session table including a plurality of entries;

and

wherein the session tracking infrastructure is further adapted to insert entries into the session table and to remove entries from the session table responsive to accepting session establishment notifications and session termination notifications, respectively, from one or more applications.

59. The system as recited in claim 51, wherein the system further comprises:

a plurality of hosts, each host of the plurality of hosts including the session tracking infrastructure and a respective session table of a plurality of session tables; and

a plurality of load balancing units corresponding to at least a portion of the load balancing infrastructure, the at least a portion of the load balancing infrastructure comprising a session tracking manager that is distributed over the plurality of load balancing units.

60. The system as recited in claim 51, wherein the system further comprises:

a plurality of hosts resident at a plurality of devices, each host of the plurality of hosts including the session tracking infrastructure and a respective session table of a plurality of session tables; and

a plurality of load balancing units comprised of at least one device and corresponding to at least a portion of the load balancing infrastructure, the at least a portion of the load balancing infrastructure comprising a session tracking manager that is distributed over the plurality of load balancing units.

61. The system as recited in claim 51, wherein the system further comprises:

a plurality of hosts resident at a plurality of devices, each host of the plurality of hosts including the session tracking infrastructure and a respective session table of a plurality of session tables; and

a plurality of load balancing units comprised of at least one device and corresponding to at least a portion of the load balancing infrastructure, the at least a portion of the load balancing infrastructure comprising a session tracking manager that is distributed over the plurality of load balancing units;

wherein the session tracking infrastructure comprises a remote part of the load balancing infrastructure.

62. The system as recited in claim 51, wherein the system further comprises:

a plurality of hosts resident at a plurality of devices, each host of the plurality of hosts including the session tracking infrastructure and a respective session table of a plurality of session tables; and

a plurality of load balancing units comprised of at least one device and corresponding to at least a portion of the load balancing infrastructure, the at least a portion of the load balancing infrastructure comprising a session tracking manager that is distributed over the plurality of load balancing units;

wherein the at least one device is one of the plurality of devices.

63. The system as recited in claim 51, wherein the load balancing infrastructure comprises a distributed session tracking manager that manages a distributed table of session information entries.

64. The system as recited in claim 51, wherein the load balancing infrastructure comprises a distributed session tracking manager that manipulates a distributed table of session information entries using a plurality of function calls for adding, deleting, querying, and returning session information entries of the distributed table.

65. The system as recited in claim 51, wherein the load balancing infrastructure comprises a distributed session tracking manager that manages a distributed table of session information entries using a level of replication that is at least one.

66. The system as recited in claim 51, wherein the load balancing infrastructure comprises a distributed session tracking manager that manages a distributed table of session information entries using local caching upon acquisition of a given session information entry.

67. The system as recited in claim 51, wherein the load balancing infrastructure comprises a distributed session tracking manager that manages a distributed table of session information entries using hashing for location selection of replicated session information entries.

68. The system as recited in claim 51, wherein the load balancing infrastructure comprises (i) a distributed session tracking manager that manages a distributed table of session information entries and (ii) traffic routing functionality that is adapted to interact with the distributed session tracking manager in order to utilize the session information when routing connection requests to the plurality of hosts.

69. The system as recited in claim 51, wherein the session tracking infrastructure and the load balancing infrastructure are capable of using a communication protocol for transmitting messages therebetween that relate to the session information.

70. The system as recited in claim 69, wherein the communication protocol comprises a session up message type and a session down message type.

71. The system as recited in claim 70, wherein a format for the session up message type includes a session identifier and a host identifier;

and wherein a format for the session down message type includes the session identifier.

72. The system as recited in claim 71, wherein the session identifier varies by session type, and the host identifier comprises a network address of a host of the plurality of hosts on which a session identified by the session identifier established.

73. One or more processor-accessible media comprising processor-executable instructions that, when executed, direct a system to perform actions comprising:

acquiring session information for a plurality of session contexts from one or more applications that established the plurality of session contexts; and

routing network traffic to the one or more applications responsive to the acquired session information.

74. The one or more processor-accessible media as recited in claim 73, wherein the action of acquiring comprises an action of:

acquiring session information that indicates when the plurality of session contexts are established and terminated by the one or more applications.

75. The one or more processor-accessible media as recited in claim 73, wherein the action of acquiring comprises an action of:

acquiring the session information for the plurality of session contexts from the one or more applications via notifications of an application programming interface (API).

76. The one or more processor-accessible media as recited in claim 73, wherein the action of acquiring comprises an action of:

acquiring the session information for the plurality of session contexts from session tracking infrastructure via messages of a communications protocol.

77. The one or more processor-accessible media as recited in claim 73, comprising the processor-executable instructions that, when executed, direct the system to perform a further action comprising:

replicating the session information across a plurality of load balancing units.

78. The one or more processor-accessible media as recited in claim 73, comprising the processor-executable instructions that, when executed, direct the system to perform a further action comprising:

replicating session information for a particular session context of the plurality of session contexts at one or more additional devices of the system.

79. The one or more processor-accessible media as recited in claim 73, comprising the processor-executable instructions that, when executed, direct the system to perform a further action comprising:

replicating session information for a particular session context of the plurality of session contexts at one or more additional devices based on a hash value derived from a session indicator for the particular session context.

80. The one or more processor-accessible media as recited in claim 73, comprising the processor-executable instructions that, when executed, direct the system to perform further actions comprising:

receiving the acquired session information from a plurality of hosts; and

caching the received session information in a distributed table.

81. The one or more processor-accessible media as recited in claim 73, comprising the processor-executable instructions that, when executed, direct the system to perform further actions comprising:

receiving the acquired session information from a plurality of hosts;

caching the received session information in a distributed table;

receiving a connection request that references a particular session context of the plurality of session contexts; and

consulting the cached session information for the connection request;

wherein the action of routing comprises an action of;

routing the network traffic to the one or more applications responsive to the consulting.

82. The one or more processor-accessible media as recited in claim 81, wherein the action of caching comprises at least one action of:

calling an add session information function to add the received session information to the distributed table.

83. The one or more processor-accessible media as recited in claim 73, wherein the one or more processor-accessible media comprise at least one of (i) one or more storage media and (ii) one or more transmission media.

84. The one or more processor-accessible media as recited in claim 73, wherein at least a portion of the processor-executable instructions comprise at least part of a load balancing software program.

85. The one or more processor-accessible media as recited in claim 73, wherein at least a portion of the processor-executable instructions are adapted to run on the system wherein the system comprises a single device.

86. The one or more processor-accessible media as recited in claim 73, wherein at least a portion of the processor-executable instructions are adapted to run on the system wherein the system comprises a plurality of devices.

87. The one or more processor-accessible media as recited in claim 73, wherein the action of routing comprises an action of:

routing the network traffic to the one or more applications responsive to the acquired session information in order to enable a client to continue a particular session context of the plurality of session contexts at a host that includes the application of the one or more applications that established the particular session context of the plurality of session contexts.

88. An arrangement for network load balancing with session information, the arrangement comprising:

means for acquiring session information from one or more applications; and

means for making load balancing decisions responsive to the acquired session information.

89. The arrangement as recited in claim 88, wherein the means for acquiring is located at a plurality of hosts, and the means for making is located at load balancing infrastructure;

and

wherein the arrangement further comprises;

means for communicating the acquired session information from the plurality of hosts to the load balancing infrastructure with host indicators.

90. The arrangement as recited in claim 88, wherein the means for acquiring comprises means for acquiring connection-specific session information from the one or more applications, and the means for making comprises means for making the load balancing decisions responsive to the acquired connection-specific session information.

91. The arrangement as recited in claim 88, wherein the arrangement comprises at least one system.

92. The arrangement as recited in claim 88, wherein the arrangement comprises one or more processor-accessible media.

93. One or more processor-accessible media comprising processor-executable instructions that, when executed, direct a system to perform actions comprising:

analyzing a connection request having a session reference;

searching a local portion of a distributed table with regard to the session reference, the distributed table having a plurality of session information entries;

determining, responsive to the searching, if the session reference matches a session identifier of a particular session information entry of a subset of the plurality of session information entries that are in the local portion of the distributed table; and

if so, extracting the particular session information entry having the session identifier that matches the session reference.

94. The one or more processor-accessible media as recited in claim 93, comprising the processor-executable instructions that, when executed, direct the system to perform a further action comprising:

receiving from a client the connection request having the session reference.

95. The one or more processor-accessible media as recited in claim 93, comprising the processor-executable instructions that, when executed, direct the system to perform further actions comprising:

ascertaining a host having session affinity with respect to the session reference as indicated by a host identifier that is in the extracted particular session information entry; and

routing the connection request to the host having the session affinity with respect to the session reference.

96. The one or more processor-accessible media as recited in claim 93, comprising the processor-executable instructions that, when executed, direct the system to perform further actions comprising:

if it is determined that the session reference does not match a session identifier in the local portion of the distributed table, making a query function call for a matching session information entry that is not in the local portion of the distributed table but that does have a session identifier that matches the session reference; and

receiving, as a result of the making a query function call, the matching session information entry from a non-local portion of the distributed table.

97. The one or more processor-accessible media as recited in claim 96, comprising the processor-executable instructions that, when executed, direct the system to perform a further action comprising:

making an add-session-information-entry function call that adds the received matching session information entry to the local portion of the distributed table.