3270 EIS/FMI Applications Fail if RU size in BIND Set To 32 KB (195883)

SYMPTOMS

3270 EIS (Emulator Interface Specification)/FMI (Function Management Interface) applications used with SNA Server fail if the application BIND received from the host specifies an RU (Request Unit) size of 32 KB. SNA Server will send the BIND to the 3270 application in an OPEN PLU REQUEST message. The 3270 Applet included with SNA Server responds to this message with an OPEN PLU CONFIRM ERROR (Err1:0821 Err2:000A). SNA Server then sends a BIND -RSP to the host with an IBM Sense Code of 0835000A. Other 3270 applications may return slightly different errors.

This problem also occurs when using TN3270. In this case, SNA Server sends a BIND +RSP back to the host if the RU Size is 32 KB. However, a subsequent RUI READ verb fails with a LUA_RU_LENGTH_ERROR message.

CAUSE

SNA Server stores the maximum RU size in a signed two-byte integer which is capable of storing values up to +32767. The value of 32 KB is 32768, which is larger than can be stored in that signed two-byte integer. As a result, all FMI applications using 32 KB RUs are rejected.

RESOLUTION

Microsoft has confirmed this to be a problem in SNA Server Versions 3.0, 3.0 SP1, 3.0 SP2, 3.0 SP3, 4.0, and 4.0 SP1. We are researching this problem in SNA Server version 3.0 and will post more information here in the Knowledge Base as it becomes available.

This problem was corrected in the latest SNA Server version 4.0 U.S. Service Pack. For information on obtaining this Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

MORE INFORMATION

Please refer to the IBM SNA Formats Guide (GA27-3136) for more details on how the RU size is specified in the BIND. IBM Sense Codes are also documented in this manual, which is also available on the SNA Server 4.0 CD (I386\Sdk\Formats.hlp).