Overview

You notice that AO-MT messages with reverse charging do not query OCS, resulting in no charges.

The following symptoms may be present:

• Diameter error 4001 is issued by SMSC.
• SMSR-DB is checked for B-number.
• AO-MT to Postpaid works fine, MT is delivered, CDR is issued.
• No Diameter request to OCS, no CCR.

Solution

In the SMPP trace, check if the originating application sends the Submit-sm with recipient TON/NPI = 0/0 (unk/unk). If that is the case, request the SMPP application owner to send messages with recipient NPI set to 1 (E.164). If possible, also set TON to 1 if they are always sending messages with recipient in international format.

The first byte (2 digits) of the Originator or Recipient addresses carries the TON/NPI information. It'd be usually set to "91" for international format MSISDN's (TON = 1 and NPI = 1 (E.164), plus a reserved bit set in the front). For a value like '60', it means TON = abbreviated ; NPI = 0 (unknown).

In many cases, if the originator of the messages does not send them in the correct international format, SMSC will normalize these addresses and set the correct TON/NPI on them. However, when no "Address Conversion Rules" are configured in the GUI, the SMSC works with default behavior; it will just perform some basic normalization on the received addresses.