System and method for reliable packet data transport in a computer network

A system for reliably transmitting over a computer network requests, from client applications to server applications, the system comprising:

• a client computer having a central processing unit and a memory;
• a plurality of client-side functions on the client computer to perform reliable transport-related tasks for client applications, including a function that returns a starting sequence number and range of allowable sequence numbers for request messages;
• a client application on the client computer and configured to create a request to a server application running on a server computer and to identify one or more of the plurality of client-side functions to be used with the client application to perform reliable transport-related tasks for the client application;
• a client-side transport protocol stack on the client computer which receives request messages and transmits them to a server-side transport protocol stack;
• and
• a client-side application protocol stack on the client computer which
• receives from the client application the identification of one or more of the plurality of client-side functions to be used with the client application to perform reliable transport-related tasks for the client application and receives for transmission a request from the client application,
• wraps the request in a request message, wherein wrapping the request comprises adding a header to the request, the header including an identifying sequence number assigned by the client-side application protocol stack and a type code identifying the type of the request message as a request,
• calls the identified one or more of the plurality of client-side functions to obtain one or more parameters associated with reliability of the transmission,
• utilizes the one or more parameters to provide aspects of the reliability of the transmission of the request, and
• sends the resulting request message to the client-side transport protocol stack;
• wherein the client-side application protocol stack retransmits the request message if a message is not received from a server-side transport protocol stack which contains the sequence number of the request message and a type code that indicates before the time-out period for i-th transmission has elapsed since the request message was transmitted for the i-th time and the number of times that the request message has been transmitted is less than a total allowed number of transmissions;
• and
• wherein if a message received by the client-side application protocol stack from the server-side transport protocol stack contains the sequence number of the request message and a type code that indicates that it is a provisional reply message to the request message, then the current time-out period for retransmission is modified to delay its expiration.

A method for reliably transmitting over a computer network requests, from client applications running on a client computer to server applications running on a server computer based upon parameters indicated by the client applications, the client computer having a central processing unit, memory, a client-side application protocol stack, a plurality of client-side functions to perform reliable transport-related tasks, including a function that returns a starting sequence number and range of allowable sequence numbers for request messages, and a client-side transport protocol stack, the server computer having a central processing unit, memory, a server-side application protocol stack, a plurality of server-side functions and a server-side transport protocol stack, the method comprising:

• the client-side application protocol stack
• receiving from a client application an indication of a selected set of one or more of the plurality of client-side functions for use with a request from the client application to perform reliable transport-related tasks,
• receiving for transmission the request from the client application,
• wrapping the request in a request message, including adding a header to the request, the header including an identifying sequence number assigned by the client-side application protocol stack and a type code identifying the type of the request message as a request,
• selecting and calling, based upon the indication from the client application, the selected set of one or more of the plurality of client-side functions to obtain at least one parameter for governing one or more aspects of reliability of the transmission,
• utilizing the at least one parameter to provide aspects of the reliability of the transmission of the request, and sending the resulting request message to the client-side transport protocol stack;
• the client-side transport protocol stack receiving the request message and transmitting it to the server-side transport protocol stack;
• the server-side transport protocol stack receiving the request message from the client-side transport protocol stack and sending received request message to the server-side application protocol stack;
• the server-side application protocol stack unwraps the request from the request message and sends the request to the server application;
• wherein the client-side application protocol stack retransmits the request message if a message is not received from the server-side transport protocol stack which contains the sequence number of the request message and a type code that indicates before the time-out period for i-th transmission has elapsed since the request message was transmitted for the i-th time and the number of times that the request message has been transmitted is less than a total allowed number of transmissions;
• and
• wherein if a message received by the client-side application protocol stack from the server-side application protocol stack contains the sequence number of the request message and a type code that indicates that it is a provisional reply message to the request message, then the current time-out period for retransmission is modified to delay its expiration.