Calls Fail with "503 Service Unavailable," with Alarm "out of steering ports" on Oracle AP SBC (Doc ID 2162901.1)

Last updated on MAY 16, 2017

Applies to:

Integrated Software for Acme Packet 4500 - Version S-Cz7.2.0 and later
Information in this document applies to any platform.

Symptoms

Customer recently performed an upgrade from 720m5p2 to 730m1p7.   After this update, new alarms: "out of steering ports" were shown for several child realms.  This condition lead to calls dropping, with error "503 Service Unavailable."

In this scenario, we saw this behavior only impacted child realms, which use steering-pool ports from its parent realm.

Troubleshooting this further, the show mbcd realm command shows a lot of "No Port" events in the counters. 
This documents the number of times when SBC tried assigning a steering-pool port, but there was no free port, and as a result call dropped.

<<< show mbcd realms
14:23:42-37
--- Steering Ports --- ----------- Bandwidth Usage----------
Realm Used Free No Ports Flows Ingrss Egress IngrssPriority EgressPriority Total Insuf BW
xxx1 0 0 572 0 0K 0K 0K 0K 0K 0
xxx2 4 396 0 0 0K 0K 0K 0K 0K 0
xxx3 0 0 396 0 0K 0K 0K 0K 0K 0
xxx4 0 400 0 0 0K 0K 0K 0K 0K 0
xxx5 0 0 216 0 0K 0K 0K 0K 0K 0
xxx6 2 398 0 0 0K 0K 0K 0K 0K 0
xxx7 0 0 68 0 0K 0K 0K 0K 0K 0


There was no increase in traffic, this configuration and amount of steering-pool ports configured worked well earlier.

With this we can suspect, that there may be stuck ports, and are not released from previous calls. As a result, new calls, do not get any free port.

Changes

Customer performed upgrade from 720m5p2 to 730m1p7.

Cause

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