2.1.5.10 CRP Service Action Handler

The Circular Route Prevention (CRP) Service Action Handler attempts to detect a circular route.

The CRP Service Action must have a higher precedence that the NPRLS Service Action, which is a terminating action.

Configuration Options Used

The TIFOPTS NPFLAG configuration option indicates when and how the NM bits should be processed.

The TIFOPTS CRPREL configuration option indicates the Release Cause code to be included in the Release message.

Actions Performed

If the TIFOPTS NPFLAG configuration option is set to NM and the NM bits indicate that a lookup has already been performed, then the Service Action Handler returns immediately. (NM bits are used in-network only. If the NM bits have been set, then portability has already been checked in the network. Another CRP check is not needed.)

If the NM bits indicate that a lookup has not already been performed, the Number Portability lookup is performed. If an RN is returned, then it is assumed that the number was ported and that a circular route is detected.

A Release Cause code will be included, and a Redirection Number will not be included, in the outgoing Release message.

The NPP Formatting Action processing will be skipped when a circular route is detected. One way to force formatting of the outgoing CdPN is to configure the CDIAL Service Action.

Terminating Action?

If a circular route is detected, then this is a terminating action.