Acme Packet SD6300 7.2.0 Disconnects A Forked Call After RE-INVITE

Asset ID:	1-72-2009548.1
Update Date:	2015-05-19
Keywords:

Solution Type Problem Resolution Sure

Solution 2009548.1 : Acme Packet SD6300 7.2.0 Disconnects A Forked Call After RE-INVITE

Applies to:

Acme Packet 6300 - Version S-Cz7.0.2 to S-Cz7.2.5 [Release S-Cz7.0]
Information in this document applies to any platform.
Call drops when the call is answered by devices behind IMS forking server.

Symptoms

Call comes from PSTN on the Cisco gateway and the Cisco gateway sends the call to ACME SBC, which then sends the call to a landline phone, if the phone is answered there is no issue.
However, if the call is not answered by the landline phone, the call goes to mobile phones via IMS forking server, using a parallel forking technique. When the call is answered on the mobile phone, the call is dropped.

The SBC will be shown to terminate BOTH call legs.

Changes

Upgraded the SBC from SD4250 6.1.0 to SD6300 7.2.0

Cause

New Feature added in 6.2

When hairpinned calls are ended because of signaling failures (such as a SIP mid-dialog signaling timeout, or an H.
323 TCP keepalive failure) on one call leg, the Oracle Communications Session Border Controller deletes both legs’
media flows simultaneously by default. In addition, when the first hairpinned call leg is torn down, the second call leg
is gracefully released immediately by the Oracle Communications Session Border Controller creating and sending an
appropriate signaling message (e.g., BYE for a SIP call or ReleaseComplete for an H.323 call) to the endpoint.

You can override this behavior by configuring the dont-terminate-assoc-legs option in the media manager.
When configured, the orphaned call leg in the hairpin scenario will be torn down after the initial guard
timer expires.

The issue is happening because SBC terminates both legs of the call when the call is answered by the mobile device.

Solution

1) Enable dont-terminate-assoc-legs in media-manager options configuration.

2) Reboot SBC for the changes to take effect.

Proces to enable the feature

LAB# conf t
LAB(configure)# media-manager media-manager
LAB(media-manager-config)# select
LAB(media-manager-config)# options dont-terminate-assoc-legs
LAB(media-manager-config)# done

**LAB# save

*LAB# reboot activate

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