sense code 800A sent by AIXSNA

Problem with SNA Server trying to download file from DB2 MVS
using 8k RU size getting SNA Server error: "0105-1126:
sense code = 800a0000"

Customer is connecting to DB2 on an MVS host using VTAM 3.1.5.  

When the customer uses an RU size of 4k, he can successfully transfer
"large' data files.  When he increases the RU size (from LU6.2 mode
profile) to 8k from 4k, he gets a sense code 800a0000: PIU is too long.
In response to FMDData from the host. PIU is too long, the transmission
was truncated. The PIU exceeded the maximum length or sufficient
buffering was not available.

Same type of error message with the same sense code in DB2 MVS.  
On the sna server side, the customer receives following messages:
0105-1126 - SNA protocol violation
0105-1156 - Aborting process

Env:  AIX 4.1.3   SNA Server 3.1  Token Ring LS
RS/6000 Model G30, DB2 2.1,  VTAM 3.1.5,  3745 NCP V?.?,  DDCS ???
.Desc:  TPN=0x07F6C4C2 (.6DB) fails with RU_size=8KB; works with 4KB

WORKAROUND is to use smaller RU-sizes.

Env:  AIX 4.1.3   SNA Server 3.1  Token Ring LS
RS/6000 Model G30, DB2 2.1,  VTAM 3.1.5,  3745 NCP V?.?,  DDCS ???
routers or bridges ???
.Desc:  TPN fails with RU_size=8KB; works with 4KB
   XID --->
   0x0fce=4046 max I-field
   652  TR 400079999996 10205  -----------BIND rq------------>
   654  TR 4000000AAA1C 10502  \<----------BIND +rsp------------
        max_ru=0x8a 8192 bytes
   656  TR 400079999996 10205  -----------FMH5 rq------------>
        ATTACH  now have active conversation
   660  TR 400079999996 10205  ----------FMDData rq---------->
   664  TR 4000000AAA1C 10502  \<----------FMDData rq-----------

   Several FMD data RU's are exchanged.
   697  TR 4000000AAA1C 10502  \----------FMDData rq-----------
        VTAM  0000029 B O  00000001 1B35 0004  DCF=08195  (RH+RU)
        [ 2E0002050004 ] [ 07B100 ]
        FMD RU [ 800A0000 0016D0 ]
        VTAM sent the first large RU; RU_SIZE is maximum (8192) agreed
        at BIND time.  AIXSNA receives this PIU with only a 7 byte RU,
        RQE3, SD set, and 800A 0000 sense data.   The last 3 bytes
        are the first 3 bytes from the original RU so that the
        offending RU can be identified.  
   699  TR 400079999996 10205  ------FMDData -rsp(800a0000)------
        [ 2E0005020004 ] [ 87B000 ]
        AIXSNA half-session detects SD set and returns the -rsp with 
        the same sense data as the received request.  AIXSNA ends the 
        session with an unbind.  Another PIU is received but it is 
        rejected with 8005 because the session has already ended from 
        AIXSNA's perspective.
   703  TR 400079999996 10205  ----------UNBIND rq----------->
   707  TR 4000000AAA1C 10502  \<----------FMDData rq-----------
   709  TR 400079999996 10205  ------FMDData -rsp(80050000)------>
   Customer needs to determine which node in path from VTAM to AIXSNA
   changes the FMD data RU into a REQUEST with 800A sense data set.

VTAM was truncating PIU's because VTAM was not correctly configured
for large RU's.  
Sense 800A0000 on a PIU that should have been 8195 long.                
Customer had coded BFRS=240 and TRANSFER=16.....much to small.

   Configure VTAM to support large RU's as described in
   VTAM configuration manuals.

Support Line: sense code 800A sent by AIXSNA ITEM: AR2761L
Dated: February 1996 Category: N/A
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