Disable the ISUP ACC function using the raw API

The ISUP Automatic Congestion Control (ISUP ACC) procedure is defined in Section 2.11, ITU-T Recommendation Q.764 (1997), Signalling System No. 7 – ISDN user part signalling procedures. 

Dialogic IMG Integrated Media Gateway supports the ISUP ACC function by default. 

When an IMG receives a release message containing an automatic congestion level parameter, the IMG reports alarm 0x3a in Dialogic Gate Control Element Management System (GCEMS) EventView. The IMG will reduce its traffic to the overload-affected exchange. 

When the overloaded exchange returns to a normal traffic load it will stop including the automatic congestion level parameters in its release messages. The IMG will then, after a predetermined time (5 seconds), automatically return to the normal status and clear the alarm 0x3a in EventView.

This note describes a way to disable the ISUP ACC function on an IMG using the raw API.
 

Procedure:

PPL Config Byte 1 in PPL Component ISUP ACC (Automatic Congestion Control - PPL id 0x00A8) is used to Enable/Disable the ACC Remote Algorithm
 

0x00=Disable
0x01=Enable (default)

Here is an example, disabling the ISUP ACC function on SS7 stack id 0, SS7 destination id 0:
 

00 12 00 d7 00 00 00 00 01 1c 03 01 00 01 00 a8 01 01 01 00 

API 0x00D7 - PPL Configure
AIB 0x1C - SS7 Destination ID
AIB length : 03
SS7 stack id: 0
SS7 destination id : 0000
PPL id: 0x00a8 ISUP ACC
PPL Entity : 01
Number of Data Locations: 01
Location 1 Byte Number: 01 Enable/Disable ACC Remote Algorithm
Location 1 Data: 00 (Disable) 01 (Enable)

You can find the SS7 stack id and destination id in Dialogic ClientView for the particular SS7 destination which reports congestion. 

Glossary of Acronyms / Terms

ISUP - ISDN User Part
DPC - Destination Point Code
ACL - Automatic congestion level
ISUP CIC - Circuit Identification Code
ISUP IAM - Initial Address Message
ISUP REL - Release Message