Methods, systems and computer program products for resuming SNA application-client communications after loss of an IP network connection

• US 7,089,311 B2
• Filed: 01/31/2001
• Issued: 08/08/2006
• Est. Priority Date: 01/31/2001
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Huang, Sue L., Devine, Wesley McMillan, Trottman, Douglas Alan
• Primary Examiner(s): Prieto, Beatriz
• Assistant Examiner(s): Meucci, Michael D.
• Application Number:
  US09/773,437
• Publication Number:
  US 20020103909A1
• Time in Patent Office: 2,015 Days
• Field of Search: 709/220, 709223-224, 709227-228
• US Class Current: 709/227
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion
• 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 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04L 69/169 Special adaptations of TCP, UDP or IP for interworking of IP based networks with other networks protocols for interworking, protocol conversion H04L69/08
• CPC Class Codes: H04L 69/327 in the session layer [OSI layer 5]
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

Systems, methods and computer program products are provided for preserving a session between an SNA application and a TN3270E server after loss of an IP network connection between the TN3270E server and a TN3270E client that is communicating with the SNA application via the SNA session.

Claims

1. A method for preserving a session between an SNA application and a TN3270E server after loss of an IP connection between the TN3270E server and a TN3270E client that is associated with the session, the method comprising:

reestablishing the IP connection between the TN3270E server and the TN3270E client; and

then

forwarding a screen refresh request to the SNA application;

receiving a screen refresh from the SNA application; and

forwarding the screen refresh to the TN3270E client over the reestablished IP connection, wherein forwarding a screen refresh request to the SNA application comprises sending an LUSTAT message to the SNA application.

2. The method of claim 1, wherein the method further comprises:

receiving a user logon, screen from the SNA application in response to an LUSTAT message;

forwarding the user logon screen to the TN3270E client;

receiving the user logon information from the TN3270E client

checking the authenticity of the received user logon information; and

forwarding the screen refresh to the TN3270E client over the reestablished IP connection only if the received user logon information is authentic.

3. The method of claim 2, wherein forwarding a screen refresh request to the SNA application, receiving a screen refresh from the SNA application, and forwarding the screen refresh to the TN3270E client over the reestablished IP connection are performed by the TN3270E server.

4. The method of claim 1, wherein the screen refresh received from the SNA application and forwarded to the TN3270E client comprises a last data screen that was forwarded from the SNA application and acknowledged as received by the TN3270E client.

5. The method of claim 1, wherein the method further comprises:

receiving a user logon screen from the SNA application in response to the screen refresh request;

forwarding the user logon screen to the TN3270E client;

receiving logon information from the TN3270E client

checking the authenticity of the received logon information; and

resuming the session if the received logon information is authentic.

6. The method of claim 1, wherein the IP connection comprises a TCP/IP connection.

7. A system for preserving a session between an SNA application and a TN3270E server after loss of an IP connection between the TN3270E server and a TN3270E client that is associated with the session, comprising:

means for reestablishing the P connection between the TN3270E server and the TN3270E client;

means for forwarding a screen refresh request to the SNA application;

means for receiving a screen refresh from the SNA application; and

means for forwarding the screen refresh to the TN3270E client over the reestablished IP connection, wherein forwarding a screen refresh request to the SNA application comprises sending an LUSTAT message to the SNA application.

8. A computer program product for preserving a session between an SNA application and a TN3270E server after loss of an IP connection between the TN3270E server and a TN3270E client that is associated with the session, the computer program product comprising a computer usable storage medium having computer readable program code means embodied in the medium, the computer readable program code means comprising:

computer readable program code means for reestablishing the IP connection between the TN3270E server and the TN3270E client;

computer readable program code means for forwarding a screen refresh request to the SNA application;

computer readable program code means for receiving a screen refresh from the SNA application; and

computer readable program code means for forwarding the screen refresh to the TN3270E client over the reestablished IP connection, wherein forwarding a screen refresh request to the SNA application comprises sending an LUSTAT message to the SNA application.

9. A method for preserving a session between an SNA application server and a second server after loss of an IP connection between the second server and an SNA client that is associated with the session, the method comprising:

reestablishing the IP connection between the second server and the SNA client;

receiving a screen refresh request from the SNA client over the reestablished IP connection;

forwarding a screen refresh request to the SNA application server;

receiving a screen refresh from the SNA application server in response to the screen refresh request;

forwarding the screen refresh to the SNA client over the reestablished IP connection, wherein forwarding a screen refresh request to the SNA application server comprises sending an LUSTAT message to the SNA application server.

10. The method of claim 9, wherein the method further comprises:

receiving a user logon screen from the SNA application server in response to the LUSTAT message;

forwarding the user logon screen to the SNA client;

receiving logon information from the SNA client;

checking the authenticity of the received logon information; and

forwarding the screen refresh to the SNA client over the reestablished IP connection only if the received logon information is authentic.

11. The method of claim 9, wherein the screen refresh received from the SNA application server and forwarded to the SNA client comprises a last data screen that was forwarded from the SNA application server and acknowledged as received by the SNA client.