SCTP Connection Parameters From "Connection Configuration Set" Not Taken Into Account by DSR

Asset ID:	1-72-2257682.1
Update Date:	2017-12-13
Keywords:

Solution Type Problem Resolution Sure

Solution 2257682.1 : SCTP Connection Parameters From "Connection Configuration Set" Not Taken Into Account by DSR

Applies to:

Oracle Communications Diameter Signaling Router (DSR) - Version DSR 7.3.0 to DSR 7.4.0 [Release DSR 7.0]
Information in this document applies to any platform.

Symptoms

DSR aborts the SCTP connection after 1000 ms while "Retransmit Maximum Timeout for INIT" parameter in "Connection Configuration Set" is set to a higher value (>1000ms).

In the following example, the applied "Connection Configuration Set" is including the following parameter:

Retransmit Initial Timeout: 2000ms
Retransmit Minimum Timeout: 2000ms
Retransmit Maximum Timeout: 2000ms
Retransmit Maximum Timeout for INIT: 2000ms

However, in the below capture, the MP (1.1.1.1) is sending an ABORT 1000ms after the INIT was sent:

[admusr@DA-MP]$ sudo tshark -i any -R 'ip.addr== 1.1.1.1 || ip.addr== 2.2.2.2'
Running as user "root" and group "root". This could be dangerous.
Capturing on Pseudo-device that captures on all interfaces
2.630353340 1.1.1.1 -> 2.2.2.2 SCTP 156 INIT
3.631565005 1.1.1.1 -> 2.2.2.2 SCTP 56 ABORT
3.717479076 2.2.2.2 -> 1.1.1.1 SCTP 812 INIT_ACK

Cause

This is a Diameter Connection Layer (DCL) Bug (Bug 23124057). There is a hard-coded internal timeout used by some other specific processes which is superseding the SCTP parameters configured in "Connection Configuration Set". This Timeout is applied to all connection attempts, which is too small for customers operating with higher RTTs (e.g. satellite links).

Solution

A final Fix of Bug 23124057 is provided with DSR 8.0 Release.

However, Bug 23331980 made the concerned Timeout configurable on DSR 7.3 & DSR 7.4 releases.

To change this Timeout, follow the below procedure:

Connect to the Active System Operation, Administration & Maintenance (SOAM) server as admusr
Run the following command to get the parameter updated (in below case, it was set to 2000ms. You may change 2000 by the value you want to implement:

iset -fvalue=2000 DpiOption where "name='MaxConnectTimeout'"

References

<BUG:23124057> - DCL: RE-FACTOR CONNECTION INITIATION
<BUG:23331980> - CONNECT TIMEOUT TO BE MADE CONFIGURABLE
<NOTE:2335648.1> - Diameter Signaling Router (DSR) – After Upgrade From 7.0.1 to 7.2, DSR sends Abort For Some SCTP Connections

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