1. DSR TIF User's Guide
  2. TIF Features
  3. TIF Number Portability Feature
  4. TIF NP Service Action Handlers
  5. Use of NM Bits

2.1.5.3 Use of NM Bits

The Number Portability Forward Call Indicator NM bit values as shown in the following table are used in ISUP IAM messages to indicate CdPN portability status.

Table 2-3 NM Bits Values

NM Bits Value Meaning
00 "Without indication" - DPC is out-of-network, or no Number Portability lookup performed
01 "Query not performed" - DPC is in-network, Number Portability lookup was not performed
10 "Query performed, not ported" - DPC is in-network, unsuccessful Number Portability lookup
11 "Query performed, ported" - DPC is in-network, successful Number Portability lookup

Use of NM Bits is optional, and is controlled by the TIFOPTS NPFLAG configuration option and by the destination-based NPRST configuration option for the DPC of the incoming message.

TIF determines the value of the NM Bits in the incoming message. The following CdPN-based Service Action Handlers inspect the incoming NM Bits value: NPRELAY, NPRLS, NPNRLS, and CRP.
  • If TIFOPTS NPFLAG=NM and the incoming NM Bits value is 10 or 11, the Service Action Handler ends processing immediately.
  • If TIFOPTS NPFLAG=NM and the NPRELAY Service Action Handler performs an Number Portability lookup on the CdPN, TIF uses the NM Bits value indicated by the NPRELAY processing to determine if the NM Bits value needs to be updated in the outgoing IAM message.
  • If TIFOPTS NPFLAG=NM, the incoming NM Bits value is 01, the NPRLS Service Action Handler performs an Number Portability lookup on the CdPN, and no match is found, the NPRLS Service Action Handler sends a RELEASE message with no Redirection Number and the Release Cause set to the value of the TIFOPTS RCAUSENP option.

Note:

The configuration options and the NM Bits apply only to the CdPN, not to the CgPN. Therefore, the CgPNSVCRQD Service Action Handler does notCgPNSVCRQD and CGPNNP Service Action Handlers do not look at the NM bits. The NM Bits apply only for ITU ISUP messages when TIFOPTS NPFLAG=NM.
If the TIFOPTS NPFLAG configuration option is set to NM and the outgoing message NM bits are not 00, the Destination table is searched for the DPC from the IAM message.
  • If the NPRST option valued in the Destination table entry is ON, the NM bits in the outgoing message are set to 00 ("without indication").
  • If the NPRST option valued in the Destination table entry is OFF, the NM bits in the outgoing message are not set to 00.