GSM 09.02 - Version 5.3.0 - Digital cellular telecommunications - ETSI

2) Inter-PLMN addressing
Page 39
GSM 09.02 version 5.3.0: August 1996
a) Called Party Address
- SSN indicator = 1 (MAP SSN always included);
- Global title indicator = 0100 (Global title includes translation type, numbering plan,
encoding scheme and nature of address indicator);
- the translation type field will be coded "00000000" (Not used);
- Routing indicator = 0 (Routing on global title);
b) Calling Party Address
- SSN indicator = 1 (MAP SSNs always included);
- Point code indicator = 0;
- Global title indicator = 0100 (Global title includes translation type, numbering plan,
encoding scheme and nature of address indicator);
- the translation type field will be coded "00000000" (Not used);
- Routing indicator = 0 (Routing on Global Title).
When an SCCP UNITDATA message is sent, the Called Party Address is derived from the Called Address
of the N-UNITDATA-REQUEST primitive issued by the local TC. The Calling Party Address received in the
dialogue initiating SCCP UNITDATA message is forwarded to the local TC of the dialogue responding
entity as Calling Address within the N-UNITDATA-INDICATION primitive in order to be stored as Called
Address for the current transaction.
In the case of intra-PLMN addressing, it may be necessary to complement the Calling Party Address
received in the dialogue initiating SCCP UNITDATA message by the associated Originating Point Code
taken from the MTP-TRANSFER-INDICATION primitive as indicated above. In this case, the Signalling
Point Code included in the Calling Address forwarded to the local TC on receipt of the dialogue initiating
message is used as Destination Point Code for MTP routeing of all messages sent by the dialogue
responding entity within one dialogue.
For supporting the GSM protocol for inter-PLMN addressing, SCCP shall not modify the SCCP address
information received in an SCCP UNITDATA message before forwarding it to the local TC. In particular,
the Calling Party Address received within the dialogue initiating message shall not be complemented by a
Signalling Point Code before forwarding it to TC as Calling Address in the N-UNITDATA-INDICATION
primitive. Any modification of the SCCP address information received in an SCCP UNITDATA message in
the case of inter-PLMN addressing constitutes a PLMN specific option.
For supporting the GSM protocol, the options provided by ITU-T (03/93) SCCP for processing of the
Called Address received from the local TC in the N-UNITDATA-REQUEST primitive shall be restricted as
follows: If the Called Address received from TC in the N-UNITDATA-REQUEST primitive contains a Global
Title, a Destination Point Code shall be established by means of Global Title translation. In the case of
inter-PLMN signalling, the Global Title translation shall result in "routing on Global Title". PLMN specific
requirements may cause application of a different option provided by ITU-T (03/93) SCCP.