Allow COMTI LU6.2 Send Size to be Configurable.

• Microsoft COM Transaction Integrator for CICS and IMS, version 4.0 SP2
• Microsoft SNA Server, versions 4.0, 4.0SP1, 4.0SP2

SYMPTOMS

The SNA Server COM Transaction Integrator (COMTI) feature currently sends LU6.2 application data messages to the host system using a send size of 32763 bytes (32 KB). However, a customer implemented a CICS application which only receives data in 24-KB chunks, making large data transfers less efficient when used with COMTI.

At the customer's request, COMTI has been enhanced to allow the LU6.2 send size to be configurable.

CAUSE

COMTI wasn't originally designed to allow the LU6.2 send size to be configurable.

RESOLUTION

To resolve this problem, obtain the latest service pack for SNA Server version 4.0. For additional information, please see the following article in the Microsoft Knowledge Base:

Q215838 How to Obtain the Latest SNA Server Version 4.0 Service Pack

WORKAROUND

The host CICS application could be modified to receive data in 32-KB chunks, or post additional RECEIVE calls if the sent data cannot be received in a single RECEIVE call.

STATUS

Microsoft has confirmed this to be a problem in SNA Server 4.0, 4.0 SP1, 4.0 SP2. This problem was first corrected in SNA Server version 4.0 Service Pack 3.

MORE INFORMATION

With this update applied, the COMTI send size can be configured within Component Builder under the Advanced tab for each method. The send size is configured under the Set Explicit Send Size Block field, where valid values are from 1 to 32763. To implement a 24-Kb send size, the value should be 24576, or whatever the host is expecting.

The customer implemented the 24-KB LU6.2 application data receive size within the host CICS application because of an apparent recommendation within the IBM CICS/ESA V4R1 Application Programming Guide (Document Number SC33-1169-00), topic 2.1.4 - LENGTH options. However, general LU6.2 tranaction programming references do not make such a recommendation, and support LU6.2 application data send/receive sizes of 32 KB.

Additional query words:

Keywords : sna4sp3fix
Version : WINDOWS:4.0,4.0 SP2,4.0SP1,4.0SP2
Platform : WINDOWS
Issue type : kbbug