The Gateway Screening and MSU Tracing (GWST) application screens and redirects traffic based on the TCAP message content using the Allowed TCAP Op Codes screening table (see the following figure).

Allowed TCAP Op Code Configuration Screen


If a TCAP screened MSU does not include a TCAP op code, the MSU is treated as a successful gateway screening. This behavior is the standard and default handling for GWS MSU decode failures and inapplicable screening criteria.

This TCAP screening criteria definition may cause limitations for certain traffic patterns, such as SMS traffic, which may contain only the TCAP application context as relevant information. Screening and consequently redirection of MSUs with undefined optional operation codes using other TCAP fields, such as the message type and application context, are supported by the TCAP Op Code Optional feature.

The TCAP Op Code Optional feature is configurable in the GWST Configuration object's General Configuration screen using the TCAP Op Code Optional attribute (see the following figure). 

Note

This attribute is set to DISABLED by default.

GWST Configuration General Screen

To configure the TCAP Op Code Optional feature

  1. From the Main Menu, click GWS and MSU Tracing.

  2. Modify the TCAP Op Code Optional attribute, and click Continue.
        

To create an Allowed TCAP Op Code for an undefined operation code

Note

The TCAP Op Code Optional feature must be enabled before you can execute this procedure for the NOT PRESENT value (see the proceeding procedure).

  1. From the Main Menu, click GWS and MSU Tracing.
     
  2. Click GWST Tables.

  3. Click Allowed TCAP Op Codes.
        
  4. Click Create Allowed TCAP Op Code.
     

  5. Configure the required attributes including the Op Code Range to either NOT PRESENT or '*' value and then click Create.