AMPX036I Assertion Failure Checking Error in TCTOCTC
APAR Identifier ...... PQ70168 Last Changed ........ 03/02/03
AMPX036I ASSERTION FAILURE CHECKING ERROR IN TCTOCTC
Symptom ...... IN INCORROUT Status ........... CLOSED PER
Severity ................... 2 Date Closed ......... 03/01/30
Component .......... 5735FAL00 Duplicate of ........
Reported Release ......... 320 Fixed Release ............ 999
Component Name TCP/IP V2 FOR V Special Notice
Current Target Date .. Flags
SCP ...................
Platform ............
Status Detail: PACKAGING - Solution is being packaged for
shipment.
PE PTF List:
PTF List:
Release 3A0 : UQ73774
Release 320 : UQ73775
Release 410 : UQ73776
Release 420 : UQ73777
Release 430 : UQ73778
Parent APAR:
Child APAR list:
ERROR DESCRIPTION:
FTP VM to remote host connected via VCTC hangs the LINK.
TCPIP reports assertion errors and then hangs the link:
AMPX036I ASSERTION FAILURE CHECKING ERROR
TRACE BACK OF CALLED ROUTINES
ROUTINE STMT AT ADDRESS IN MODULE
PACKWRITES 27 00DB8CD0 TCTOCTC_TOC
TOCTC 69 00DBAD64 TCTOCTC_TOC
SCHEDULER 113 00D4F43E TCSCHED_SCH
<MAIN-PROGRAM> 22 00CBE284 TCPIP
VSPASCAL 00E28B92
AMPX036I ASSERTION FAILURE CHECKING ERROR
TRACE BACK OF CALLED ROUTINES
ROUTINE STMT AT ADDRESS IN MODULE
PACKWRITES 27 00DB8CD0 TCTOCTC_TOC
TOCTC 15 00DBAB12 TCTOCTC_TOC
CALLPROCRTN 9 00D14248 TCPARSE_PAR
SCHEDULER 86 00D4F2A2 TCSCHED_SCH
<MAIN-PROGRAM> 22 00CBE284 TCPIP
VSPASCAL 00E28B92
LOCAL FIX:
PROBLEM SUMMARY:
****************************************************************
* USERS AFFECTED: Users with real or virtual *
* Channel-to-channel (CTC) links defined with *
* MTU sizes of 32768 and a Large Envelope size *
* of 32768 *
****************************************************************
* PROBLEM DESCRIPTION: An assertion failure occurs if an *
* attempt is made to send a 32K datagram *
* over a CTC link. *
****************************************************************
* RECOMMENDATION: APPLY PTF *
****************************************************************
A CTC link uses a buffer size of 32K in which it packs as many
datagrams as will fit. Each datagram is preceded in the buffer
by a six-byte header and the block is preceded by a two-byte
header. Consequently, a single datagram can be at most 32760
bytes long.
When an attempt is made to send a datagram longer than 32760
bytes, the CTC driver produces an assertion failure and requeues
the offending envelope for transmission. When another datagram
is queued for transmission, the original too-large datagram is
dequeued, causing another assertion failure and requeing the
envelope again. At this point, no further activity occurs since
there is a datagram in the envelope queue for the link.
An additional assertion failure occurs each time there is
incoming traffic on the link.
PROBLEM CONCLUSION:
Code has been changed to drop envelopes containing datagrams
that are too large for the CTC link. If TRACE CTC is in effect
then message
DTCCTC005E CTCA device <name>: <size>-byte datagram exceeds
CTC buffer size
will be produced each time this situation is detected.
To prevent datagrams from being dropped, the MTU size for a CTC
link should not exceed 32760.
TEMPORARY FIX:
COMMENTS:
MODULES/MACROS: FPTOCTC MSTCP TCPIP TCTOCTC
SRLS: NONE
RTN CODES:
CIRCUMVENTION:
MESSAGE TO SUBMITTER: