End-to-end session recovery

• US 5,754,752 A
• Filed: 03/28/1996
• Issued: 05/19/1998
• Est. Priority Date: 03/28/1996
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Tandem Computers Incorporated (HP Inc.)
• Inventors: Sheh, Yi-Ren Peter, Schroeder, Roger James
• Primary Examiner(s): DAVIS JR, WALTER D
• Application Number:
  US08/625,532
• Time in Patent Office: 782 Days
• Field of Search: 395/182.02, 395/200.33, 395/200.57, 395/200.58
• US Class Current: 714/4.4
• CPC Class Codes: G06F 11/1443 Transmit or communication errors
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/08 specially adapted for terminal emulation, e.g. Telnet

Abstract

A session recovery mechanism that permits the recovery of a session with a minimal delay to a user and with minimal data loss. When the client/server communications protocol process, such as TCP/IP process, issues an error message to a server and a client, the server and the client switch from a server data socket and a client data socket, respectively, to a new server data socket and a new client data socket, respectively. This switchover is achieved by having the client open a listening socket during its initialization process. Using the client listening socket, the client listens for a connection from the server to switch to a new data socket, in case of, for example, error messages from the TCP/IP process.

Claims

1. A server apparatus for recovering a session between a server and a client, the server apparatus comprising:

a communication protocol portion for providing communication between the server and a client including

a portion for providing a server listening socket,

a portion for providing a server data socket; and

a portion for providing a new server data socket for communicating data to the client for switching from the server data socket to the new server data socket, when the communication protocol portion generates an error message.

2. A method for recovering a session between a server and a client, the method performed by a processor having a memory, comprising the steps of:

determining, by the server, that the client understands end-to-end protocol;

receiving an error message, by the server, from a communication protocol process;

closing, by the server, a first data socket; and

opening, by the server, a second data socket for communicating data to the client.

3. The method of claim 2, wherein the step of determining includes the steps of:

detecting a new connection by the client;

opening the first data socket; and

requesting terminal type data from the client.

4. The method of claim 3, wherein the step of determining further includes the step of requesting, by the server a second time, terminal type data from the client.

5. The method of claim 4, further comprising the step of receiving, by the server from the client, a socket number associated with a client listening socket.

6. The method of claim 2, further comprising the step of sending, by the server, a command to a client listening socket for receipt by the client.

7. The method of claim 2, further comprising the step of sending, by the server, a command to a new client listening socket for receipt by the client for recovering another session between a server and a client.

8. The method of claim 2, wherein the step of opening a second data socket for communicating data to the client includes the step of sending data to a new client data socket.

9. The method of claim 2, further comprising the step of generating, by the server, a session ID.

10. The method of claim 9, wherein the step of generating the session ID includes the step of generating the session ID by use of a time stamp combined with secret text.

11. The method of claim 9, further comprising the step of sending, by the server, the session ID to the client.

12. The method of claim 2, further comprising the step of requesting, by the server, terminal type data from the client.

13. The method of claim 12, further comprising the step of requesting, by the server, a session ID from the client.

14. The method of claim 13, further comprising the step of establishing a connection, by the server, through the second data socket and a new client data socket.

15. An apparatus for recovering a session between a server and a client, the apparatus comprising:

means for using an end-to-end protocol including;

means for determining, by the server a first time, that the client understands end-to-end protocol;

means for receiving an error message, by the server, from a communication protocol process;

means for determining, by the server a second time, that the client understands end-to-end protocol;

means for closing, by the server, a first data socket; and

means for opening, by the server, a second data socket for communicating data to the client.

16. A computer program product comprising:

a computer usable medium having computer readable program code means embodied therein for causing a recovery of a session between a server computer and a client, the computer readable program code means in the computer program product comprising;

computer readable program code means configured to cause the server computer to determine that the client understands end-to-end protocol;

computer readable program code means configured to cause the server computer to receive an error message from a communication protocol process;

computer readable program code means configured to cause the server computer to effect closing a first data socket; and

computer readable program code means configured to cause the server computer to effect opening a second data socket for communicating data to the client.