ISUP PROT VIOL Output in the CLI Terminal

Symptom

A message reporting "ISUP PROT VIOL" is output on the CLI Terminal of a Dialogic IMG Integrated Media Gateway.
 

Reason for the issue

An incorrect ISUP variant has been configured.

The output above gives the following information about the ISUP protocol violation:

DPC: 0x000003d8
CIC (From): 0x0037
CIC Range (To): 0x0037
SS7 Stack id: 0
Comp : 0x12 (SS7 PPL Component id 0x12 - ISUP CPC)
err : 4 (Error Type 4 - Maximum Parameter Length Violation)
mid : 0x01 (ISUP message id 1 - IAM)
pid : 0x0a (ISUP parameter id 0x0a - Calling Party Number)

The pre-1997 ITU ISUP specification defines the maximum parameter length of the Calling Party Number parameter as 12 bytes. 

The post-1997 ITU ISUP specification changed the maximum length to 'unlimited' (Table 32/Q.763, ITU-T Recommendation Q.763 (1997), Signaling System No. 7 – ISDN User Part formats and codes).

Message Type: Initial address
 

NOTE 2 – Peer-to-peer interworking with an earlier version of ISUP may result in format errors and lead to the release of the call.

Fix / Solution

Select 'ITU 97' or ETSIv3 as the ISUP variant when configuring the IMG 1004, IMG 1010 or IMG 2020 SS7 Stack. Also speak to your SS7 provider / carrier about what ISUP variant is being used on the affected links.

ISUP protocol violation Error Type List:
NOTE: Entries marked with a dagger (†) report the ISUP message type only and do not report an ISUP parameter.
0x01† Unrecognized Message Type
0x02 Unrecognized Parameter ID
0x03 Minimum Parameter Length Violation
0x04 Maximum Parameter Length Violation
0x05† Corrupt Parameter Data
0x06† Mandatory Parameters Missing
0x07 Range Field of Range/Status Parameter is zero
 

Product List
Dialogic IMG 1004 Integrated Media Gateway
Dialogic IMG 1010 Integrated Media Gateway
Dialogic IMG 2020 Integrated Media Gateway (IMG 2020), formerly referred to as Dialogic BorderNet™ 2020 Session Border Controller

Glossary of Acronyms / Terms
ISUP -  ISDN User Part
ISUP CPC - Call Processing Control
DPC - Destination Point Code
ISUP CIC - Circuit Identification Code
ISUP IAM - Initial Address Message