Diameter Signaling Router (DSR) – After Upgrade From 7.0.1 to 7.2, DSR Sends Abort For SCTP Connections - Error (<connection name>:104) dsr#8006{EvFsmException}

Asset ID:	1-72-2335648.1
Update Date:	2018-03-14
Keywords:

Solution Type Problem Resolution Sure

Solution 2335648.1 : Diameter Signaling Router (DSR) – After Upgrade From 7.0.1 to 7.2, DSR Sends Abort For SCTP Connections - Error (:104) dsr#8006{EvFsmException}

Applies to:

Oracle Communications Diameter Signaling Router (DSR) - Version DSR 7.2.0 to DSR 7.4.0 [Release DSR 7.0]
Tekelec

Symptoms

It is observed that after upgrade from DSR 7.0.1 to DSR 7.2, DSR sends an SCTP (Signaling Connection transfer Protocol) ABORT for some Connections.

The following error will also be seen in the DSR logs or Event history:

dsr logs:

03/08/2018 21:06:18 (<Connection Name>:104) dsr#8006{EvFsmException}
.. GN_INFO/INF Call to connect() or sctp_connectx() failed. Connection ID=<connection ID>, errno=Timer expired (62).
^^ [16202:DiameterLogs.C:562]

Event History Report from GUI:

TIMESTAMP: 2018-03-07 20:34:53.187 UTC
NETWORK_ELEMENT: <Network Element>
SERVER: <MP Server>
SEQ_NUM: 3255366
EVENT_NUMBER: 8006
SEVERITY: INFO
PROCESS: dsr
TYPE: DIAM
INSTANCE: <Connection Name>:104
NAME: EvFsmException
DESCRIPTION: Connection FSM exception.
ERR_INFO:
GN_INFO/INF Call to connect() or sctp_connectx() failed. Connection ID=<connection id>, errno=Timer expired (62).
^^ [16202:DiameterLogs.C:562]

Changes

Upgrade from DSR 7.0.1 to DSR 7.2

Cause

According to below trace DSR (1.1.1.1) sends an SCTP ABORT 500ms after the SCTP INIT was sent

60.099746524 1.1.1.1 -> 2.2.2.2 SCTP 104 INIT
60.469623706 2.2.2.2 -> 1.1.1.1 SCTP 816 INIT_ACK
60.469687446 1.1.1.1 -> 2.2.2.2 SCTP 776 COOKIE_ECHO
60.600432145 1.1.1.1 -> 2.2.2.2 SCTP 60 ABORT
60.828433447 2.2.2.2 -> 1.1.1.1 SCTP 66 COOKIE_ACK

This issue is related to Bug# 23331980
According to the Bug a hard coded upper limit of 500ms is applied to all connection attempts, which is too small for customer operating with higher RTT (e.g. satellite links).

Solution

- In DSR 7.2 only way to fix this issue is by reducing the network RTT to be less than 500ms.
- Bug 23331980 made the parameter (MaxConnectTimeout) configurable in DSR 7.3, however this workaround can only be executed from backend (CLI – Command Line Interface).
- A permanent fix for this issue is on DSR 8.0 (Bug# 23124057) which will have this as a configurable parameter through GUI.

For Orange Patch 26934415 was created to fix this issue in DSR 7.2
MOP to apply the patch is at:

https://stbeehive.oracle.com/content/dav/st/DSR Technical Support Center (DSR TSC)/Public Documents/MOP LIBRARY/Draft - Orange FR_Prod_DSR7.2.0.0.0-72.25.0_Patch_26934415_MOP-v1.2.pdf

References

<BUG:23331980> - CONNECT TIMEOUT TO BE MADE CONFIGURABLE
<NOTE:2257682.1> - SCTP Connection Parameters From "Connection Configuration Set" Not Taken Into Account by DSR
<BUG:23124057> - DCL: RE-FACTOR CONNECTION INITIATION
<NOTE:2371887.1> - Diameter Connection Will Not Come Into Service, Shows Error (:104) dsr#8006{EvFsmException}

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