SIST EN 301 029-4:2000

SIST EN 301 029-4:2000 is the Slovenian adoption of ETSI EN 301 029-4 V1.2.1 (1998-04), a European Telecommunications Standard for Broadband Integrated Services Digital Network (B-ISDN) signalling. It specifies the Look-Ahead without state change procedure for the network node interface within the B-ISDN User Part (B-ISUP), for engineers and operators working on B-ISDN and Signalling System No.7 (SS7) implementations.

What does SIST EN 301 029-4:2000 specify?

SIST EN 301 029-4:2000 specifies the Look-Ahead without state change procedure for the network node interface. It is part 4 of the B-ISUP signalling capability set 2, step 1, and it sits within the EN 301 029 multi-part family.

The technical text is organized around Clause 3 procedures, including Subclause 3.2 on initiating exchange behavior and Subclause 3.7.1 on normal procedures. Appendix III covers Look-Ahead message flow for UNI/NNI interworking, and the ETSI endorsement notice records that this appendix is deleted in the approved version.

What are the key requirements of SIST EN 301 029-4:2000?

SIST EN 301 029-4:2000 turns the Look-Ahead procedure into exchange-level behavior and message handling rules. The main points are about who may initiate the procedure, how the destination local exchange responds, and how information is mapped into primitives.

Initiating exchange rules

• The initiating exchange can be originating, transit, gateway or destination, but not a free-standing screening point. In practice, the procedure is tied to exchanges that participate directly in call or connection control.
• When the initiating exchange is also the destination exchange, the actions are specified by DSS 2 protocol [4]. This tells implementers when another protocol governs the same situation.

Destination local exchange handling

• When a Look-Ahead AEI is instantiated on the incoming side, the destination local exchange receives an LA_Invoke.ind from the AEI. This is the entry point for the Look-Ahead exchange.
• If a request is received, the destination local exchange starts the appropriate procedure toward the user and passes on all received parameters. This preserves the information needed for the next signaling step.
• If an answer is received from the access, the destination local exchange maps the received information into parameters of the LA_Invoke.resp primitive sent to the SACF. This makes the response usable by the next functional entity.

Checks and fallback behavior

• The destination local exchange checks the user profile, subscription options and user availability. The result may populate Cause indicators in LA_Invoke.resp, so implementation teams need to connect service checks to signaling outcomes.
• If the LA procedure is not supported or implemented at UNI, the procedure in 3.7.2 applies. This gives a defined fallback path for interworking at the user network boundary.

What terms does SIST EN 301 029-4:2000 define?

• Broadband Integrated Services Digital Network (B-ISDN) - the broadband digital network environment covered by the standard.
• Signalling System No.7 (SS7) - the signalling system used for B-ISDN call and connection control.
• B-ISDN User Part (B-ISUP) - the signaling user part covered by this multi-part standard.
• network node interface (NNI) - the interface where the Look-Ahead procedure is specified.
• Look-Ahead (LA) - the procedure used to exchange information before a state change at the network node interface.
• user network interface (UNI) - the access side interface referenced in the fallback procedure.
• initiating exchange - the exchange that starts the LA procedure, including originating, transit, gateway or destination exchanges.
• destination local exchange - the exchange where the normal LA actions are carried out.

Who uses SIST EN 301 029-4:2000?

SIST EN 301 029-4:2000 is used by telecommunications engineers, signalling protocol designers, switch and exchange vendors, network operators and interoperability test teams. They use it to implement and verify B-ISDN call-control behavior, map primitives between entities, and handle UNI/NNI interworking in SS7-based networks.

What changed in SIST EN 301 029-4:2000 from the previous edition?

ETSI approved ITU-T Recommendation Q.2724.1 (1996) with agreed modifications. The notice records these changes:

• Subclause 3.2 clarifies which exchange types may initiate the LA procedure and points to DSS 2 protocol [4] when the initiating exchange is also the destination exchange.
• Subclause 3.7.1 expands the normal procedure at the destination local exchange, including parameter mapping into LA_Invoke.resp and checks of user profile, subscription options and user availability.
• Appendix III on Look-Ahead message flow for UNI/NNI interworking is deleted.

Which standards are used with SIST EN 301 029-4:2000?

SIST EN 301 029-4:2000 belongs to the EN 301 029 multi-part set for B-ISUP signalling capability set 2, step 1. It is based on ITU-T Recommendation Q.2724.1 (1996) and is used alongside the other parts of the same series.

What does the SIST EN 301 029-4:2000 document contain?

SIST EN 301 029-4:2000 contains the ETSI foreword, IPR notice, endorsement notice, transposition dates and document history, followed by the technical text for B-ISUP part 4. The technical content centers on the Look-Ahead procedure, including the roles of the initiating exchange and destination local exchange, primitive handling, parameter transfer and the checks used to build the response.

Appendix III gives the Look-Ahead message flow for UNI/NNI interworking. The endorsement notice also records the agreed changes made by ETSI to the ITU-T Recommendation text.