TCP proxy connection management in a gigabit environment

• US 8,090,866 B1
• Filed: 01/18/2002
• Issued: 01/03/2012
• Est. Priority Date: 01/18/2002
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Bashyam, Murali, Finn, Norman W., Patra, Abhijit
• Primary Examiner(s): Refai, Ramsey
• Application Number:
  US10/051,634
• Time in Patent Office: 3,637 Days
• Field of Search: 709/217, 709/212, 709/227, 709/232, 709/238
• US Class Current: 709/232
• CPC Class Codes: H04L 69/12 Protocol engines
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/165 Combined use of TCP and UDP protocols; selection criteria therefor

Abstract

The present invention describes a method and apparatus to effectively manage data buffers for a client and a server connection in a multiple connection environment. The TCP processes of servers and clients are merged into an independent TCP process in a TCP ‘proxy’ server. The TCP proxy server includes a control unit and a data switching unit (the proxy application). The TCP proxy server terminates the client TCP connection and initiates a separate TCP connection with the server. The data switching unit binds the two individual connections. The TCP proxy server portrays the actual server TCP. The control unit in the TCP proxy server manages data buffers, control memory and supports multiple connections. The control unit ‘pushes’ the data into the buffers by monitoring the use of the buffers. The control unit does not wait for data requests from the data switching unit thus, eliminating the overhead of data request messages.

Claims

1. A method of managing network communication comprising:

establishing a first transmission control protocol (“

TCP”

) connection with a first network element, wherein

said first TCP connection is between said first network element and a second network element,

said first TCP connection is intended to be established with a third network element, and

said first network element comprises a transmit buffer and a receive buffer;

initiating a second TCP connection between said first network element and said third network element;

establishing communications between said second and said third network elements via said first network element;

determining that said second network element requires additional data via said first TCP connection, wherein

said determining is performed by said first network element without said additional data being requested by said second network element, and

said determining comprises detecting that acknowledged data is being removed from said transmit buffer for said first TCP connection, wherein said detecting comprises detecting an acknowledgement sent via

said first TCP connection by said second network element, and

removal of said acknowledged data frees space in said transmit buffer;

in response to said determining, pushing said additional data from said receive buffer for said second TCP connection to said transmit buffer;

transferring said additional data from said transmit buffer to said second network element without said additional data being requested by said second network element;

closing said first TCP connection with said client in response to receiving a request for closing said connection from said data switching unit; and

performing a two-stage operation for releasing a control memory entry for said connection;

wherein said control memory entry comprises a connection block entry and a flow control entry, and said two-stage operation comprises;

releasing said connection block entry prior to receiving said request for closing said connection; and

releasing said flow control entry in response to receiving said request for closing said connection.

2. The method of claim 1, wherein said second network element initiates said first TCP connection for said third network element.

3. The method of claim 1, wherein said communications between said second and said third network elements are established using said first and said second TCP connections.

4. The method of claim 1, wherein said communications between said second and said third network elements form an end-to-end TCP connection.

5. The method of claim 1, wherein said first network element is a proxy server.

6. The method of claim 5, wherein a control unit of said proxy server monitors said transmit buffer.

7. The method of claim 6, wherein said control unit transfers said data between said second and said third network elements.

8. The method of claim 5, wherein said proxy server supports transparent communications between said second and said third network elements.

9. The method of claim 1, wherein said receive buffer is pre-allocated.

10. The method of claim 1, wherein said receive buffer is dynamically allocated.

11. The method of claim 1, wherein said transmit buffer is pre-allocated.

12. The method of claim 1, wherein said transmit buffer is dynamically allocated.

13. The method of claim 1, wherein said second network element is one of a plurality of clients.

14. The method of claim 13, wherein one of a plurality of applications on said client initiates said first TCP connection for said client.

15. The method of claim 1, wherein said third network element is one of a plurality of servers.

16. The method of claim 15, wherein a data switching unit of said proxy server determines which one of said plurality of servers to use for said second TCP connection.

17. The method of claim 1, further comprising:

monitoring said first TCP connection.

18. The method of claim 17, further comprising:

receiving a request for data from said second network element; and

determining whether said request requires said second TCP connection with one of said plurality of servers.

19. The method of claim 18, wherein data switching unit receives said request for data via said control unit.

20. The method of claim 18, wherein said determining of said second TCP connection is done by said data switching unit.

21. The method of claim 18, further comprising:

if said request does not require said second TCP connection with one of said plurality of servers,

servicing said request for data, and

closing said connection with said second network element.

22. The method of claim 21, wherein said request for data is served by passing data from said data switching unit to said control unit for transmission to an application on said second network element.

23. The method of claim 21, further comprising:

if said request requires said second TCP connection with one of said plurality of servers,

selecting a first server from said plurality of servers, and

initiating said second TCP connection with said first server.

24. The method of claim 23, wherein said application requests said end-to-end TCP connection with said first server.

25. The method of claim 23, further comprising:

receiving said data on said second TCP connection from said first server;

storing said data in said receive buffer of said second TCP connection.

26. A network device configured to:

establish a first transmission control protocol (“

TCP”

) connection with a first network element, wherein said first TCP connection is between said first network element and a second network element,

said first TCP connection is intended to be established with a third network element, and

said first network element comprises a transmit buffer and a receive buffer;

initiate a second TCP connection between said first network element and said third network element;

establish communications between said second and said third network elements via said first network element;

determine that said second network element requires additional data via said first TCP connection, wherein said determination is performed by said first network element without said additional data being requested by said second network element, and

said determination comprises a detection that acknowledged data is being removed from said transmit buffer for said first TCP connection, wherein said detection comprises detecting an acknowledgement sent via said first TCP connection by said second network element, and removal of said acknowledged data frees space in said transmit buffer;

in response to said determination, push said additional data from said receive buffer for said second TCP connection to said transmit buffer; and

transfer said additional data from said transmit buffer to said second network element without said additional data being requested by said second network element;

wherein said network device is further configured to close said first TCP connection with said client in response to receiving a request for closing said connection from said data switching unit;

request for closing said connection from said data switching unit wherein said network device is further configured to perform a two-stage operation for releasing a control memory entry for said connection, wherein said control memory entry comprises a connection block entry and a flow control entry; and

said two-stage operation comprises;

releasing said connection block entry prior to receiving said request for closing said connection; and

releasing said flow control entry in response to receiving said request for closing said connection.

27. The network device of claim 26, wherein said second network element initiates said first TCP connection for said third network element.

28. The network device of claim 26, wherein said communications between said second and said third network elements are established using said first and said second TCP connections.

29. The network device of claim 26, wherein said communications between said second and said third network elements form an end-to-end TCP connection.

30. The network device of claim 26, wherein said first network element is a proxy server.

31. The network device of claim 30, wherein a control unit of said proxy server monitors said transmit buffer.

32. The network device of claim 31, wherein said control unit transfers said data between said second and said third network elements.

33. The network device of claim 30, wherein said proxy server supports transparent communications between said second and said third network elements.

34. The network device of claim 26, wherein said receive buffer is pre-allocated.

35. The network device of claim 26, wherein said receive buffer is dynamically allocated.

36. The network device of claim 26, wherein said transmit buffer is pre-allocated.

37. The network device of claim 26, wherein said transmit buffer is dynamically allocated.

38. The network device of claim 26, wherein said second network element is one of a plurality of clients.

39. The network device of claim 38, wherein one of a plurality of applications on said client initiates said first TCP connection for said client.

40. The network device of claim 26, wherein said third network element is one of a plurality of servers.

41. The network device of claim 40, wherein a data switching unit of said proxy server determines which one of said plurality of servers to use for said second TCP connection.

42. The network device of claim 26, wherein said network device is further configured to monitor said first TCP connection.

43. The network device of claim 42, wherein said network device is further configured to receive a request for data from an application on a client and determine whether said request requires said second TCP connection with one of a plurality of servers.

44. The network device of claim 43, wherein a data switching unit receives said request for data via a control unit.

45. The network device of claim 43, wherein said determining of said second TCP connection is done by a data switching unit.

46. The network device of claim 43, wherein said network device is further configured to if said request does not require said second TCP connection with one of said plurality of servers,

service said request for data, and

close said connection with said client.

47. The network device of claim 46, wherein said request for data is served by passing data from said data switching unit to said control unit for transmission to said application on said client.

48. The network device of claim 46, wherein said network device is further configured to if said request requires said second TCP connection with one of said plurality of servers,

select a first server from said plurality of servers, and

initiate said second TCP connection with said first server.

49. The network device of claim 48, wherein said application requests said end-to-end TCP connection with said first server.

50. The network device of claim 48, wherein said network device is further configured to receive said data on said second TCP connection from said first server;

store said data in said receive buffer of said second TCP connection.

51. A network device comprising:

means for establishing a first transmission control protocol (“

TCP”

) connection with a first network element, wherein said first TCP connection is between said first network element and a second network element,

said first TCP connection is intended to be established with a third network element, and said first network elements comprises a transmit buffer and a receive buffer;

means for initiating a second TCP connection between said first network element and said third network element;

means for establishing communications between said second and said third network elements via said first network element;

means for determining that said second network element requires additional data via said first TCP connection, wherein said determining is performed by said means for determining without said additional data being requested by said second network element, and

said determining comprises detecting that acknowledged data is being removed from said transmit buffer for said first TCP connection, wherein said means for detecting comprises means for detecting an acknowledgement sent via said first TCP connection by said second network element, and

removal of said acknowledged data frees space in said transmit buffer;

means for pushing said additional data from said receive buffer for said second TCP connection to said transmit buffer, in response to said determining;

means for transferring said additional data from said transmit buffer to said second network element without said additional data being requested by said second network element;

means for closing said first TCP connection with said client in response to receiving a request for closing said connection from said data switching unit if said request for data from said application is served; and

means for performing a two-stage operation for releasing a control memory entry for said connection, wherein said control memory entry comprises a connection block entry and a flow control entry and said two-stage operation comprises;

releasing said connection block entry prior to receiving said request for closing said connection and releasing said flow control entry in response to receiving said request for closing said connection.

52. The network device of claim 51, wherein said second network element initiates said first TCP connection for said third network element.

53. The network device of claim 51, wherein said communications between said second and said third network elements are established using said first and said second TCP connections.

54. The network device of claim 51, wherein said communications between said second and said third network elements form an end-to-end TCP connection.

55. The network device of claim 51, wherein said first network element is a proxy server.

56. The network device of claim 55, wherein a control unit of said proxy server monitors said transmit buffer.

57. The network device of claim 56, wherein a control unit transfers said data between said second and said third network elements.

58. The network device of claim 55, wherein said proxy server supports transparent communications between said second and said third network elements.

59. The network device of claim 51, wherein said receive buffer is pre-allocated.

60. The network device of claim 51, wherein said receive buffer is dynamically allocated.

61. The network device of claim 51, wherein said transmit buffer is pre-allocated.

62. The network device of claim 51, wherein said transmit buffer is dynamically allocated.

63. The network device of claim 51, wherein said second network element is one of a plurality of clients.

64. The network device of claim 63, wherein one of a plurality of applications on said client initiates said first TCP connection for said client.

65. The network device of claim 51, wherein said third network element is one of a plurality of servers.

66. The network device of claim 65, wherein a data switching unit of a proxy server determines which one of said plurality of servers to use for said second TCP connection.

67. The network device of claim 51, further comprising:

means for monitoring said first TCP connection.

68. The network device of claim 67, further comprising:

means for receiving a request for data from an application on a client; and

means for determining whether said request requires said second TCP connection with one of a plurality of servers.

69. The network device of claim 68, wherein a data switching unit receives said request for data via a control unit.

70. The network device of claim 68, wherein said determining of said second TCP connection is done by a data switching unit.

71. The network device of claim 68, further comprising:

means for servicing said request for data if said request does not require said second TCP connection with one of said plurality of servers; and

means for closing said connection with said client if said request does not require said second TCP connection with one of said plurality of servers.

72. The network device of claim 71, wherein said request for data is served by passing data from said data switching unit to said control unit for transmission to said application on said client.

73. The network device of claim 71, further comprising:

means for selecting a first server from said plurality of servers if said request requires said second TCP connection with one of said plurality of servers; and

means for initiating said second TCP connection with said first server if said request requires said second TCP connection with one of said plurality of servers.

74. The network device of claim 73, wherein said application requests said end-to-end TCP connection with said first server.

75. The network device of claim 73, further comprising:

means for receiving said data on said second TCP connection from said first server;

means for storing said data in said receive buffer of said second TCP connection.

76. The network device of claim 75, further comprising:

means for requesting said additional data from said first server if said first TCP connection needs said additional data.

77. The network device of claim 76, wherein said additional data is transferred into said transmit buffer without a request for said additional data.

78. A computer program product for managing network communication, encoded in computer readable media, said program product comprising a set of instructions executable on a computer system, said set of instructions configured to:

establish a first transmission control protocol (“

TCP”

) connection with a first network element, wherein said first TCP connection is between said first network element and a second network element,

said first TCP connection is intended to be established with a third network element, and

said first network element comprises a transmit buffer and a receive buffer;

initiate a second TCP connection between said first network element and said third network element;

establish communications between said second and said third network elements via said first network element;

determine that said second network element requires additional data via said first TCP connection, wherein said determining is performed by said first network element without said additional data being requested by said second network element, and

said determining comprises detect that acknowledged data is being removed from said transmit buffer for said first TCP connection, wherein detection that acknowledged data is being removed comprises detection of an acknowledgement sent via said first TCP connection by said second network element, and removal of said acknowledged data frees space in said transmit buffer;

in response to said determination, push said additional data from said receive buffer for said second TCP connection to said transmit buffer; and

transfer said additional data from said transmit buffer to said second network element without said additional data being requested by said second network element;

wherein said set of instructions is further configured to;

if said request for data from said application is served, close said first TCP connection with said client in response to receiving a request for closing said connection from said data switching unit; and

wherein said set of instructions is further configured to perform a two-stage operation for releasing a control memory entry for said connection, wherein said control memory entry comprises a connection block entry and a flow control entry, and said two-stage operation comprises;

releasing said connection block entry prior to receiving said request for closing said connection; and

releasing said flow control entry in response to receiving said request for closing said connection.

79. The computer program product of claim 78, wherein said second network element initiates said first TCP connection for said third network element.

80. The computer program product of claim 78, wherein said communications between said second and said third network elements are established using said first and said second TCP connections.

81. The computer program product of claim 78, wherein said communications between said second and said third network elements form an end-to-end TCP connection.

82. The computer program product of claim 78, wherein said first network element is a proxy server.

83. The computer program product of claim 82, wherein a control unit of said proxy server monitors said plurality of buffers.

84. The computer program product of claim 82, wherein said control unit transfers said data between said second and said third network elements.

85. The computer program product of claim 82, wherein said proxy server supports transparent communications between said second and said third network elements.

86. The computer program product of claim 78, wherein said receive buffer is pre-allocated.

87. The computer program product of claim 78, wherein said receive buffer is dynamically allocated.

88. The computer program product of claim 78, wherein said transmit buffer is pre-allocated.

89. The computer program product of claim 78, wherein said transmit buffer is dynamically allocated.

90. The computer program product of claim 78, wherein said second network element is one of a plurality of clients.

91. The computer program product of claim 90, wherein one of a plurality of applications on said client initiates said first TCP connection for said client.

92. The computer program product of claim 78, wherein said third network element is one of a plurality of servers.

93. The computer program product of claim 92, wherein a data switching unit of said proxy server determines which one of said plurality of servers to use for said second TCP connection.

94. The computer program product of claim 78, wherein said set of instructions is further configured to:

monitor said first TCP connection.

95. The computer program product of claim 94, wherein said set of instructions is further configured to:

receive a request for data from an application on a client; and

determine whether said request requires said second TCP connection with one of a plurality of servers.

96. The computer program product of claim 95, wherein a data switching unit receives said request for data via a control unit.

97. The computer program product of claim 95, wherein said determining of said second TCP connection is done by said data switching unit.

98. The computer program product of claim 95, wherein said set of instructions is further configured to:

if said request does not require said second TCP connection with one of said plurality of servers,

service said request for data, and

close said connection with said client.

99. The computer program product of claim 98, wherein said request for data is served by passing data from said data switching unit to said control unit for transmission to said application on said client.

100. The computer program product of claim 98, wherein said set of instructions is further configured to:

if said request requires said second TCP connection with one of said plurality of servers,

select a first server from said plurality of servers, and

initiate said second TCP connection with said first server.

101. The computer program product of claim 100, wherein said application requests said end-to-end TCP connection with said first server.

102. The computer program product of claim 100, wherein said set of instructions is further configured to:

receive said data on said second TCP connection from said first server;

store said data in said receive buffer of said second TCP connection.

103. The computer program product of claim 102, wherein said set of instructions is further configured to:

if said first TCP connection needs said additional data,

request said additional data from said first server.

104. The computer program product of claim 103, wherein said additional data is transferred into said transmit buffer without a request for said additional data.