System and method for providing tunnel connections between entities in a messaging system

• US 7,117,267 B2
• Filed: 06/28/2001
• Issued: 10/03/2006
• Est. Priority Date: 06/28/2001
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Bavadekar, Shailesh S.
• Primary Examiner(s): Jaroenchonwanit, Bunjob
• Assistant Examiner(s): Chankong, Dohm
• Application Number:
  US09/894,318
• Publication Number:
  US 20030009571A1
• Time in Patent Office: 1,923 Days
• Field of Search: None
• US Class Current: 709/230
• CPC Class Codes: H04L 12/4633 Interconnection of networks using encapsulation techniques, e.g. tunneling
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/18 End to end
• CPC Class Codes: H04L 47/19 at layers above the network layer network arrangements for networked applications for scheduling or organising the servicing of application requests H04L67/60
• CPC Class Codes: H04L 47/34 ensuring sequence integrity, e.g. using sequence numbers
• CPC Class Codes: H04L 63/029 Firewall traversal, e.g. tunnelling or, creating pinholes
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 69/326 in the transport layer [OSI layer 4] H04L69/16 takes precedence
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A system and method for providing HTTP tunnel connections between entities such as clients and servers in a messaging system is described. An HTTP tunnel connection layer is described that may be used to provide reliable, full duplex virtual connections between entities (e.g. clients and brokers) in a distributed application environment using a messaging system. Also described is a novel HTTP tunneling protocol that may be used by the HTTP tunnel connection layer. The HTTP tunnel connection layer may be used by clients to access messaging servers through proxy servers and firewalls, thus expanding the scope of from where clients can access brokers. Using this layer, brokers as well as clients may initiate messaging system messages. This layer may also provide guaranteed data delivery with correct sequencing even in case of a failure on the network. This layer may also provide end-to-end flow control.

Claims

1. A method, comprising:

establishing a transport protocol tunnel connection from a first node in a messaging system to a second node in the messaging system, wherein the second node is a messaging server configured to receive messages from a plurality of clients and deliver the messages to specified ones of a plurality of recipients according to a standard messaging API (application programming interface);

generating a messaging system message on the first node according to the standard messaging API of the messaging sever;

generating one or more transport protocol packets, wherein the one or more transport protocol packets each includes at least a part of the messaging system message; and

transmitting the one or more transport protocol packets to the second node via the transport protocol tunnel connection;

wherein the transport protocol tunnel connection provides full-duplex transmission of messaging system messages between the first node and the second node, and wherein the transport protocol tunnel connection further provides delivery of the messaging system messages in the sequence in which the messaging system messages are generated;

the second node generating an acknowledgement transport protocol packet to indicate successful receipt of the one or more transport protocol packets including the messaging system message;

wherein the acknowledgement transport protocol packet includes information indicating available space in a receive buffer on the second node, and wherein the information indicating available space in the receive buffer is configured for use in flow control of messaging system messages transmitted from the first node to the second node.

2. The method as recited in claim 1, further comprising storing the messaging system message in a transmit buffer on the first node after said generating the messaging system message on the first node.

3. The method as recited in claim 1, wherein the transport protocol tunnel connection passes through a proxy server.

4. The method as recited in claim 3, wherein said transmitting the one or more transport protocol packets to the second node via the transport protocol tunnel connection comprises:

transmitting the one or more transport protocol packets from the first node to the proxy server; and

transmitting the one or more transport protocol packets from the proxy server to the second node.

5. The method as recited in claim 1, wherein the transport protocol tunnel connection passes through at least one firewall.

6. The method as recited in claim 1, wherein the transport protocol tunnel connection is established through a network.

7. The method as recited in claim 6, wherein the network is the Internet.

8. The method as recited in claim 1, wherein the first node is a client in the messaging system, and wherein the second node is a broker in the messaging system.

9. The method as recited in claim 1, wherein the transport protocol tunnel connection passes through a third node, and wherein, in said transmitting the one or more transport protocol packets to the second node, the method further comprises:

transmitting the one or more transport protocol packets to the third node; and

the third node forwarding the one or more transport protocol packets to the second node.

10. The method as recited in claim 9, wherein the one or more transport protocol packets are forwarded to the second node via a Transmission Control Protocol (TCP) connection portion of the transport protocol tunnel connection between the third node and the second node.

11. The method as recited in claim 9, wherein the third node is a Web server.

12. The method as recited in claim 1, wherein the transport protocol tunnel connection passes through a proxy server arid a Web server, and wherein said transmitting the one or more transport protocol packets to the second node via the transport protocol tunnel connection comprises:

transmitting the one or more transport protocol packets from the first node to the proxy server;

transmitting the one or more transport protocol packets from the proxy server to the Web server; and

the Web server forwarding the one or more transport protocol packets to the second node.

13. The method as recited in claim 12, wherein the transport protocol tunnel connection passes through at least one firewall between the proxy server and the Web server.

14. The method as recited in claim 1, wherein the one or more transport protocol packets include messaging system message sequence information configured for use in processing two or more messaging system messages in sequence.

15. The method as recited in claim 1, further comprising:

receiving the transmitted one or more transport protocol packets on the second node; and

storing the messaging system message from the one or more transport protocol packets in a receive buffer on the second node.

16. The method as recited in claim 1, further comprising:

receiving the transmitted one or more transport protocol packets on the second node; and

transmitting the acknowledgement transport protocol packet to the first node via the transport protocol tunnel connection.

17. The method as recited in claim 16, further comprising:

storing the messaging system message from the received one or more transport protocol packets in a receive buffer on the second node.

18. The method as recited in claim 17, further comprising:

receiving the transmitted acknowledgement transport protocol packet on the first node;

generating one or more messaging system messages on the first node;

storing the one or more messaging system messages in a transmit buffer on the first node;

determining from the information indicating available space in the receive buffer included in the received acknowledgement transport protocol packet if there is space available to receive the one or more messaging system messages on the second node;

if said determining indicates there is space available to store the one or more messaging system messages in the receive buffer of the second node;

generating a second one or more transport protocol packets, wherein the second one or more transport protocol packets include the one or more messaging system messages; and

transmitting the second one or more transport protocol packets to the second node via the transport protocol tunnel connection; and

if said determining indicates there is not space available to store the second messaging system message in the receive buffer of the second node, inhibiting generating the second one or more transport protocol packets including the one or more messaging system messages.

19. The method as recited in claim 18, further comprising:

the first node receiving a transport protocol packet indicating available space in the receive buffer of the second node;

determining from the information indicating available space in the receive buffer included in the received transport protocol packet that there is space available to receive the one or more messaging system messages on the second node;

generating the second one or more transport protocol packets, wherein the second one or more transport protocol packets include the one or more messaging system messages; and

transmitting the second one or more transport protocol packets to the second node via the transport protocol tunnel connection.

20. The method as recited in claim 16, wherein the transport protocol tunnel connection passes through a third node, and wherein, in said transmitting the acknowledgement transport protocol packet to the first node, the method further comprises:

transmitting the acknowledgement transport protocol packet to the third node; and

storing the acknowledgement transport protocol packet in a transport protocol packet buffer on the third node.

21. The method as recited in claim 20, wherein, in said transmitting the acknowledgement transport protocol packet to the first node, the method further comprises:

the first node transmitting a transport protocol request packet to the third node; and

the third node transmitting the acknowledgement transport protocol packet stored in the transport protocol packet buffer to the first node via the transport protocol tunnel connection in response to the transport protocol request packet.

22. The method as recited in claim 21, wherein the acknowledgement transport protocol packet is transmitted to the third node via a Transmission Control Protocol (TCP) connection portion of the transport protocol tunnel connection.

23. The method as recited in claim 16, wherein the transport protocol tunnel connection passes through a third node, and wherein, in said transmitting the acknowledgement transport protocol packet to the first node, the method further comprises:

transmitting the acknowledgement transport protocol packet to the third node; and

the third node forwarding the acknowledgement transport protocol packet to the first node.

24. The method as recited in claim 23, wherein the acknowledgement transport protocol packet are forwarded to the first node via a Transmission Control Protocol (TCP) connection portion of the transport protocol tunnel connection.

25. The method as recited in claim 1, wherein the transport protocol tunnel connection passes through a third node, and wherein, in said transmitting the one or more transport protocol packets to the second node via the transport protocol tunnel connection, the method further comprises:

transmitting the one or more transport protocol packets to the third node; and

storing the one or more transport protocol packets in a transport protocol packet buffer on the third node.

26. The method as recited in claim 25, wherein, in said transmitting the one or more transport protocol packets to the second node via the transport protocol tunnel connection, the method further comprises:

the second node sending one or more transport protocol request packets to the third node; and

the third node transmitting the one or more transport protocol packets stored in the transport protocol packet buffer to the second node via the transport protocol tunnel connection in response to the one or more transport protocol request packets.

27. The method as recited in claim 25, wherein the third node is a Web server.

28. The method as recited in claim 1, wherein the transport protocol is Hypertext Transport Protocol (HTTP).

29. The method as recited in claim 1, wherein the transport protocol is one of UDP (User Datagram Protocol), IrDA (Infrared Data Association), SNA (Systems Network Architecture), IPX (Internetwork Packet eXchange), and Bluetooth.

30. A method, comprising:

establishing a Hypertext Transport Protocol (HTTP) tunnel connection from a first node in a messaging system to a second node in the messaging system, wherein the second node is a messaging server configured to receive messages from a plurality of clients and deliver the messages to specified ones of a plurality of recipients according to a standard messaging API (application programming interface);

generating a messaging system message on the first node according to the standard messaging API of the messaging sever;

generating one or more HTTP packets, wherein the one or more HTTP packets each includes at least a part of the messaging system message;

transmitting the one or more HTTP packets to the second node via the HTTP tunnel connection;

wherein the HTTP tunnel connection provides full-duplex transmission of messaging system messages between the first node and the second node, and wherein the HTTP tunnel connection further provides delivery of the messaging system messages in the sequence in which the messaging system messages are generated;

the second node generating an acknowledgement HTTP packet to indicate successful receipt of the one or more HTTP packets including the messaging system message, wherein the acknowledgement HTTP packet includes information indicating available space in the receive buffer.

31. The method as recited in claim 30, wherein the first node is a client in the messaging system, wherein the HTTP tunnel connection passes through a proxy server, and wherein said transmitting the one or more HTTP packets to the second node via the HTTP tunnel connection comprises:

transmitting the one or more HTTP packets from the client to the proxy server; and

transmitting the one or more HTTP packets from the proxy server to the second node.

32. The method as recited in claim 30, wherein the HTTP tunnel connection is established through the Internet, and wherein the HTTP tunnel connection passes through at least one firewall.

33. The method as recited in claim 30, wherein the first node is a client in the messaging system, and wherein the second node is a broker in the messaging system.

34. The method as recited in claim 30, wherein the HTTP tunnel connection passes through a Web server, wherein the second node is a broker in the messaging system, and wherein, in said transmitting the one or more HTTP packets to the second node, the method further comprises:

transmitting the one or more HTTP packets to the Web server; and

the Web server forwarding the one or more HTTP packets to the broker via a Transmission Control Protocol (TCP) connection portion of the HTTP tunnel connection between the Web server and the broker.

35. The method as recited in claim 30, wherein the first node is a client in the messaging system, wherein the second node is a broker in the messaging system, wherein the HTTP tunnel connection passes through a proxy server and a Web server, and wherein said transmitting the one or more HTTP packets to the broker via the HTTP tunnel connection comprises:

transmitting the one or more HTTP packets from the client to the proxy server;

transmitting the one or more HTTP packets from the proxy server to the Web server; and

the Web server forwarding the one or more HTTP packets to the broker;

wherein the HTTP tunnel connection passes through at least one firewall between the proxy server and the Web server.

36. The method as recited in claim 30, wherein the one or more HTTP packets include messaging system message sequence information configured for use in processing two or more messaging system messages in sequence.

37. The method as recited in claim 30, further comprising:

receiving the transmitted one or more HTTP packets on the second node;

storing the messaging system message from the one or more HTTP packets in a receive buffer on the second node;

transmitting the acknowledgement HTTP packet to the first node via the HTTP tunnel connection.

38. The method as recited in claim 37, the method further comprising:

receiving the transmitted acknowledgement HTTP packet on the first node;

generating one or more messaging system messages on the first node;

storing the one or more messaging system messages in a transmit buffer on the first node;

determining from the information indicating available space in the receive buffer included in the received acknowledgement HTTP packet that there is not space available to receive the one or more messaging system messages on the second node;

the first node receiving an HTTP packet from the second node indicating available space in the receive buffer of the second node;

determining from the information indicating available space in the receive buffer included in the received HTTP packet that there is space available to receive the one or more messaging system messages on the second node;

generating a second one or more HTTP packets, wherein the second one or more HTTP packets include the one or more messaging system messages; and

transmitting the second one or more HTTP packets to the second node via the HTTP tunnel connection.

39. The method as recited in claim 37, wherein the first node is a client in the messaging system, wherein the HTTP tunnel connection passes through a Web server, and wherein, in said transmitting the acknowledgement HTTP packet to the first node, the method further comprises:

transmitting the acknowledgement HTTP packet to the Web server;

storing the acknowledgement HTTP packet in an HTTP packet buffer on the Web server;

the client sending an HTTP request packet to the Web server; and

the Web server transmitting the acknowledgement HTTP packet stored in the HTTP packet buffer to the client via the HTTP tunnel connection in response to the HTTP request packet.

40. A method comprising:

establishing a transport protocol tunnel connection from a first node in a messaging system to a second node in the messaging system;

generating a sequence of messaging system messages on the first node;

generating a plurality of transport protocol packets on the first node, wherein each of the transport protocol packets includes at least a part of one of the sequence of messaging system messages, and wherein each of the transport protocol packets includes sequence information for the particular messaging system message;

transmitting the plurality of transport protocol packets to the second node in the messaging system via the transport protocol tunnel connection;

receiving the plurality of transport protocol packets on the second node;

processing the sequence of messaging system messages on the second node, wherein said processing uses the sequence information for the plurality of messaging system messages in the plurality of transport protocol packets;

the second node generating an acknowledgement transport protocol packet for each of the received transport protocol packets to indicate successful receipt of the transport protocol packets including the sequence of messaging system messages; and

wherein each of the acknowledgement transport protocol packets includes information indicating available space in the receive buffer, wherein the information indicating available space in the receive buffer is configured for use in flow control of messaging system messages transmitted from the first node to the second node.

41. The method as recited in claim 40, wherein the transport protocol tunnel connection is established through the Internet, and wherein the transport protocol tunnel connection passes through at least one firewall.

42. The method as recited in claim 40, wherein the first node is a client in the messaging system, wherein the second node is a broker in the messaging system.

43. The method as recited in claim 40, wherein the second node is a broker in the messaging system, wherein the transport protocol tunnel connection passes through a Web server, and wherein said transmitting the plurality of transport protocol packets to the second node in the messaging system via the transport protocol tunnel connection comprises:

transmitting the plurality of transport protocol packets from the first node to the Web server; and

the Web server forwarding the plurality of transport protocol packets to the broker;

wherein the transport protocol tunnel connection passes through at least one firewall between the proxy server and the Web server.

44. The method as recited in claim 40, wherein the first node is a broker in the messaging system, wherein the second node is a client in the messaging system.

45. The method as recited in claim 40, wherein the second node is a client in the messaging system, wherein the transport protocol tunnel connection passes through a Web server, and wherein, in said transmitting the plurality of transport protocol packets to the second node in the messaging system via the transport protocol tunnel connection comprises:

transmitting the plurality of transport protocol packets to the Web server, storing the plurality of transport protocol packets in a transport protocol packet buffer on the Web server;

the client sending one or more transport protocol request packets to the Web server; and

the Web server transmitting the plurality of transport protocol packets stored in the transport protocol packet buffer to the client via the transport protocol tunnel connection in response to the one or more transport protocol request packets.

46. The method as recited in claim 40, further comprising:

storing the sequence of messaging system messages from the received transport protocol packets in a receive buffer on the second node;

transmitting the acknowledgement transport protocol packets to the first node via the transport protocol tunnel connection.

47. The method as recited in claim 40, wherein the transport protocol is Hypertext Transport Protocol (HTTP).

48. A method, comprising:

establishing a transport protocol tunnel connection from a first node in a messaging system to a second node in the messaging system;

the first node receiving a first transport protocol packet from the second node indicating available space in a receive buffer of the second node;

generating one or more messaging system messages on the first node;

storing the one or more messaging system messages in a transmit buffer on the first node;

determining from the information indicating available space in the receive buffer included in the received first transport protocol packet that there is not space available to receive the one or more messaging system messages on the second node;

the first node receiving a second transport protocol packet from the second node indicating available space in the receive buffer of the second node;

determining from the information indicating available space in the receive buffer included in the received second transport protocol packet that there is space available to receive the one or more messaging system messages on the second node;

generating one or more transport protocol packets, wherein the one or more transport protocol packets include the generated one or more messaging system messages; and

transmitting the one or more transport protocol packets to the second node via the transport protocol tunnel connection.

49. The method as recited in claim 48, wherein the transport protocol tunnel connection is established through the Internet, and wherein the transport protocol tunnel connection passes through at least one firewall.

50. The method as recited in claim 48, wherein the first node is a client in the messaging system, wherein the second node is a broker in the messaging system.

51. The method as recited in claim 48, wherein the first node is a broker in the messaging system, wherein the second node is a client in the messaging system.

52. The method as recited in claim 48, further comprising:

receiving the one or more transport protocol packets on the second node;

storing the one or more messaging system messages from the received one or more transport protocol packets in the receive buffer on the second node;

the second node generating one or more acknowledgement transport protocol packets to indicate successful receipt of the one or more transport protocol packets including the one or more of messaging system messages; and

transmitting the one or more acknowledgement transport protocol packets to the first node via the transport protocol tunnel connection;

wherein each of the acknowledgement transport protocol packets includes information indicating available space in the receive buffer.

53. The method as recited in claim 48, wherein the one or more transport protocol packets include messaging system message sequence information configured for use in processing two or more messaging system messages in sequence.

54. The method as recited in claim 48, wherein the transport protocol is Hypertext Transport Protocol (HTTP).

55. A messaging system, comprising:

a first node comprising a first memory;

a second node comprising a second memory, wherein the second node is a messaging server configured to receive messages from a plurality of clients and deliver the messages to specified ones of a plurality of recipients according to a standard messaging API (application programming interface);

wherein the first memory comprises first program instructions executable within the first node to;

establish a transport protocol tunnel connection from the first node to the second node through a network;

generate a messaging system message according to the standard messaging API of the messaging sever;

generate one or more transport protocol packets, wherein the one or more transport protocol packets each includes at least a part of the messaging system message; and

transmit the one or more transport protocol packets to the second node via the transport protocol tunnel connection;

wherein the transport protocol tunnel connection provides full-duplex transmission of messaging system messages between the first node and, the second node, and wherein the transport protocol tunnel connection further provides delivery of the messaging system messages in the sequence in which the messaging system messages are generated;

wherein the second memory comprises second program instructions executable within the second node to;

generate an acknowledgement transport protocol packer to indicate successful receipt of the one or more transport protocol packets including the messaging system message, wherein the acknowledgement transport protocol packet includes information indicating available space in a receive buffer of the second node.

56. The messaging system as recited in claim 55, wherein the first node further comprises a transmit buffer, wherein the first program instructions are further executable within the first node to store the messaging system message in the transmit buffer on the first node after said generating the messaging system message.

57. The messaging system as recited in claim 55, wherein the transport protocol tunnel connection passes through a proxy server, and wherein, in said transmitting the one or more transport protocol packets to the second node via the transport protocol tunnel connection, the first program instructions are further executable within the first node to transmit the one or more transport protocol packets from the first node to the proxy server, wherein the proxy server is configured to transmit the one or more transport protocol packets to the second node.

58. The messaging system as recited in claim 55, wherein the transport protocol tunnel connection passes through at least one firewall.

59. The messaging system as recited in claim 55, wherein the transport protocol tunnel connection is established through the Internet.

60. The messaging system as recited in claim 55, wherein the first node is a client in the messaging system, and wherein the second node is a broker in the messaging system.

61. The messaging system as recited in claim 55, wherein the messaging system further comprises:

a third node comprising a third memory;

wherein the transport protocol tunnel connection passes through the third node, and wherein, in said transmitting the one or more transport protocol packets to the second node, the first program instructions are further executable within the first node to;

transmit the one or more transport protocol packets to the third node;

wherein the third memory comprises third program instructions executable within the third node to;

receive the one or more transport protocol packets from the first node; and

forward the one or more received transport protocol packets to the second node.

62. The messaging system as recited in claim 61, wherein the one or more transport protocol packets are forwarded from the third node to the second node via a Transmission Control Protocol (TCP) connection portion of the transport protocol tunnel connection between the third node and the second node.

63. The messaging system as recited in claim 62, wherein the transport protocol tunnel connection passes through at least one firewall between the first node and the third node.

64. The messaging system as recited in claim 55, wherein the one or more transport protocol packets include messaging system message sequence information configured for use in processing two or more messaging system messages in sequence.

65. The messaging system as recited in claim 55, wherein the second memory comprises second program instructions executable within the second node to:

receive the transmitted one or more transport protocol packets;

transmit the acknowledgement transport protocol packet to the first node via the transport protocol tunnel connection.

66. The messaging system as recited in claim 65, wherein the second program instructions are further executable within the second node to:

store the messaging system message from the received one or more transport protocol packets in the receive buffer of the second node.

67. The messaging system as recited in claim 66, wherein the first node further comprises a transmit buffer, wherein the first program instructions are further executable within the first node to:

receive the transmitted acknowledgement transport protocol packet;

generate one or more messaging system messages;

store the one or more messaging system messages in the transmit buffer on the first node;

from the information indicating available space in the receive buffer included in the received acknowledgement transport protocol packet, determine if there is space available to receive the one or more messaging system messages on the second node;

if said determining indicates there is space available to store the one or more messaging system messages in the receive buffer of the second node;

generate a second one or more transport protocol packets, wherein the second one or more transport protocol packets include the one or more messaging system messages; and

transmit the second one or more transport protocol packets to the second node via the transport protocol tunnel connection; and

if said determining indicates there is not space available to store the second messaging system message in the receive buffer of the second node, inhibit generating the second one or more transport protocol packets including the one or more messaging system messages.

68. The messaging system as recited in claim 67, wherein the first program instructions are further executable within the first node to:

receive a transport protocol packet indicating available space in the receive buffer of the second node;

from the information indicating available space in the receive buffer included in the received transport protocol packet, determine that there is space available to receive the one or more messaging system messages on the second node;

generate the second one or more transport protocol packets, wherein the second one or more transport protocol packets include the one or more messaging system messages; and

transmit the second one or more transport protocol packets to the second node via the transport protocol tunnel connection.

69. The messaging system as recited in claim 65, further comprising:

a third node comprising;

a third memory; and

a transport protocol packet buffer;

wherein the transport protocol tunnel connection passes through the third node, wherein the third memory comprises third program instructions executable within the third node to;

receive the acknowledgement transport protocol packet transmitted to the first node via the transport protocol tunnel connection from the second node; and

store the received acknowledgement transport protocol packet in the transport protocol packet buffer.

70. The messaging system as recited in claim 69, wherein the first program instructions are further executable within the first node to:

transmit a transport protocol request packet to the third node; and

wherein the third program instructions are further executable within the third node to;

receive the transport protocol request packet from the first node; and

transmit the acknowledgement transport protocol packet stored in the transport protocol packet buffer to the first node via the transport protocol tunnel connection in response to the received transport protocol request packet.

71. The messaging system as recited in claim 65, further comprising:

a third node comprising a third memory, wherein the transport protocol tunnel connection passes through the third node, wherein the third memory comprises third program instructions executable within the third node to;

receive the acknowledgement transport protocol packet transmitted to the first node via the transport protocol tunnel connection from the second node; and

forward the acknowledgement transport protocol packet to the first node.

72. The messaging system as recited in claim 55, further comprising:

a third node comprising;

a third memory; and

a transport protocol packet buffer;

wherein the transport protocol tunnel connection passes through the third node, wherein the third memory comprises third program instructions executable within the third node to;

receive the one or more transport protocol packets transmitted to the second node via the transport protocol tunnel connection from the first node; and

store the one or more transport protocol packets in the transport protocol packet buffer on the third node,

wherein the second program instructions are further executable within the second node to transmit one or more transport protocol request packets to the third node; and

wherein the third program instructions are further executable within the third node to;

receive the one or more transmitted transport protocol request packets; and

transmit the one or more transport protocol packets stored in the transport protocol packet buffer to the second node via the transport protocol tunnel connection in response to the received one or more transport protocol request packets.

73. The messaging system as recited in claim 55, wherein the transport protocol is Hypertext Transport Protocol (HTTP).

74. The messaging system as recited in claim 55, wherein the transport protocol is one of UDP (User Datagram Protocol), IrDA (Infrared Data Association), SNA (Systems Network Architecture), IPX (Internetwork Packet eXchange), and Bluetooth.

75. A tangible, computer-readable medium comprising program instructions, wherein the program instructions are computer-executable to implement:

establishing a transport protocol tunnel connection from a first node in a messaging system to a second node in the messaging system, wherein the second node is a messaging server configured to receive messages from a plurality of clients and deliver the messages to specified ones of a plurality of recipients according to a standard messaging API (application programming interface);

generating a messaging system message on the first node according to the standard messaging API of the messaging sever;

generating one or more transport protocol packets, wherein the one or more transport protocol packets each includes at least a part of the messaging system message; and

transmitting the one or more transport protocol packets to the second node via the transport protocol tunnel connection;

wherein the transport protocol tunnel connection provides full-duplex transmission of messaging system messages between the first node and the second node, and wherein the transport protocol tunnel connection further provides delivery of the messaging system messages in the sequence in which the messaging system messages are generated;

generating on the second node an acknowledgment transport protocol packet to indicate successful receipt of the one or more transport protocol packets including the messaging system message, wherein the acknowledgement transport protocol packet includes information indicating available space in a receive buffer on the second node.

76. The tangible, computer-readable medium as recited in claim 75, wherein the transport protocol tunnel connection passes through a Web server, wherein the second node is a broker in the messaging system, and wherein, in said transmitting the one or more transport protocol packets to the second node, the program instructions are further computer-executable to implement:

transmitting the one or more transport protocol packets to the Web server; and

the Web server forwarding the one or more transport protocol packets to the broker via a Transmission Control Protocol (TCP) connection portion of the transport protocol tunnel connection between the Web server and the broker.

77. The tangible, computer-readable medium as recited in claim 75, wherein the first node is a client in the messaging system, wherein the second node is a broker in the messaging system, wherein the transport protocol tunnel connection passes through a proxy server and a Web server, and wherein, in said transmitting the one or more transport protocol packets to the broker via the transport protocol tunnel connection, the program instructions are further computer-executable to implement:

transmitting the one or more transport protocol packets from the client to the proxy server;

transmitting the one or more transport protocol packets from the proxy server to the Web server; and

the Web server forwarding the one or more transport protocol packets to the broker;

wherein the transport protocol tunnel connection passes through at least one firewall between the proxy server and the Web server.

78. The tangible, computer-readable medium as recited in claim 75, wherein the program instructions are further computer-executable to implement:

receiving the transmitted one or more transport protocol packets on the second node;

storing the messaging system message from the one or more transport protocol packets in a receive buffer on the second node;

transmitting the acknowledgement transport protocol packet to the first node via the transport protocol tunnel connection;

receiving the transmitted acknowledgement transport protocol packet on the first node;

generating one or more messaging system messages on the first node;

storing the one or more messaging system messages in a transmit buffer on the first node;

determining from the information indicating available space in the receive buffer included in the received acknowledgement transport protocol packet that there is space available to receive the one or more messaging system messages on the second node;

generating a second one or more transport protocol packets, wherein the second one or more transport protocol packets include the one or more messaging system messages; and

transmitting the second one or more transport protocol packets to the second node via the transport protocol tunnel connection.

79. The tangible, computer-readable medium as recited in claim 75, wherein the first node is a client in the messaging system, wherein the transport protocol tunnel connection passes through a Web server, and wherein the program instructions are further computer-executable to implement:

receiving the transmitted one or more transport protocol packets on the second node;

storing the messaging system message from the one or more transport protocol packets in a receive buffer on the second node;

the second node generating an acknowledgement transport protocol packet to indicate successful receipt of the one or more transport protocol packets including the messaging system message;

transmitting the acknowledgement transport protocol packet to the Web server;

storing the acknowledgement transport protocol packet in a transport protocol packet buffer on the Web server;

the client sending a transport protocol request packet to the Web server; and

the Web server transmitting the acknowledgement transport protocol packet stored in the transport protocol packet buffer to the client via the transport protocol tunnel connection in response to the transport protocol request packet.

80. The tangible, computer-readable medium as recited in claim 75, wherein the transport protocol is Hypertext Transport Protocol (HTTP).