A fix is available
APAR status
Closed as program error.
Error description
EZBITDSA(UK68305 11.151)+0005E0 S4C5/74FF2500 EZBUDEET(UK71936 11.258)+004AA8 S0C4/00000010 --- Abends occur as the result of a storage shortage. The dump showed many processes were waiting for TCPIP UCB lock. Elements being processed were EE TESTs (keepalive)- both requests and responses. Additional Symptoms: ABEND4C5 ABEND0C4
Local fix
Increasing the LIVTIME value on both sides of the EE connection may be beneficial to reduce the number of keep-alive flows.
Problem summary
**************************************************************** * USERS AFFECTED: All using Enterprise Extender connections. * **************************************************************** * PROBLEM DESCRIPTION: Abend ABEND4C5 reason code 74FF2500 * * when contention exists on the UCB lock * * for Enterprise Extender traffic. * **************************************************************** * RECOMMENDATION: * **************************************************************** The problem is summarized as follows: 1) EE configuration consisted of multiple local VIPAs active with connections to over 6000 EE partners. 2) At times of HPR inactivity, EE connections are issuing Test frames for "Liveness" processing. In this case, the LIVTIME was set to 10 seconds. 3) Each of these Test frames must pass through the TCP/IP FastUDP layer, which acquires the UCB lock exclusively to update route as well as policy information. 4) In this configuration, a combination of a busy system which is receiving large numbers of device interrupts along with UCB lock contention seems to be causing TCP/IP DUCBs to become suspended. This leads to a slowdown of outbound EE traffic and a growth in ECSA. In this case, ECSA growth expands until it is exhausted leading to the reported abends. Note: In the dump provided, there were over 2200 DUCBs suspended on the UCB lock. Most of these were for EE test request/responses to EE connections.
Problem conclusion
Enterprise Extender processing for outbound port 12000 traffic has been optimized to better handle large amounts of outbound traffic. The basic design is for VTAM to pass a new queueing structure, IUTIPNEE, along with IUTIL PLISTs to the TCP/IP stack when crossing the IUTSAMEH connection. This new queueing structure is similar to the IUTRPNEE structure which VTAM passes for HPR traffic originating from this host. One IUTIPNEE structure exists for each local static VIPA active for EE. This new structure allows a serialization point for outbound port 12000 traffic. If FastUDP is busy processing a previous signal for EE, a new request will simply queue up on this structure and exit processing. This exit alleviates the need for the running DUCB as well as the SRB itself. When the previous process finishes up the current request, it will simply continue to process the remaining elements until all outbound work is complete.
Temporary fix
********* * HIPER * *********
Comments
×**** PE13/07/08 FIX IN ERROR. SEE APAR OA42734 FOR DESCRIPTION
APAR Information
APAR number
OA40347
Reported component name
VTAM V4 MVS/ESA
Reported component ID
569511701
Reported release
1D0
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2012-09-11
Closed date
2012-09-24
Last modified date
2013-07-31
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UA66722 OA41280
Modules/Macros
INNERMAP ISTACMDT ISTAUCAL ISTAUCCL ISTAUCDL ISTAUCIL ISTAUCIR ISTAUCLA ISTAUCOA ISTAUNCB ISTIPNCB ISTTSCRG ISTTSCWU ISTTSC89 IUTRPNEE
Fix information
Fixed component name
VTAM V4 MVS/ESA
Fixed component ID
569511701
Applicable component levels
R1D0 PSY UA66722
UP12/12/21 P F212
Fix is available
Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.
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Document Information
Modified date:
31 July 2013