Overview
SIST EN 301 989 V1.1.1:2005 defines the requirements for signalling interworking between QSIG and H.323 protocols in corporate telecommunication networks (CN), specifically for the provision of call completion supplementary services. This Slovenian standard endorses and modifies ISO/IEC 21991 (2002), aligning European and international efforts around the seamless integration of private integrated services networks (PISN) with IP-based private telecommunication networks.
As businesses increasingly deploy both circuit-switched (QSIG) and packet-switched (H.323) technologies for telephony services, interoperability and consistent service delivery become essential. This standard ensures that supplementary services, such as call completion, can function reliably across dissimilar network technologies, thus supporting flexible network migration and modern communication infrastructure within organizations.
Key Topics
- Signalling Interworking: Specifies how signalling between QSIG (used in PISN) and H.323 (used in IP networks) must be mapped and managed for call completion services.
- Call Completion Supplementary Services: Focuses on enabling the same user experience for call completion, such as callback or camp-on, when calls traverse both QSIG and H.323 domains.
- Modifications to ISO/IEC 21991 (2002): Documents the European amendments and references to ensure regional compatibility and coherence with established ETSI standards.
- Normative References: Points to core documents such as EN 300 172, ETS 300 239, and ETS 300 366, incorporating protocols for signalling and supplementary services within private networks.
Applications
SIST EN 301 989 finds direct application in the following scenarios:
- Corporate Telephony Integration: Organizations with a mix of legacy PISN systems and modern IP-based PBXs can ensure uninterrupted call completion features when calls cross network boundaries.
- Network Modernization Projects: Supports the gradual transition from circuit-switched telephony to IP-based solutions by allowing both systems to operate simultaneously with consistent supplementary service delivery.
- Managed Service Providers: Enables telecom providers and system integrators to design, deploy, and support complex multi-protocol corporate telecommunication networks that offer standardized supplementary services.
- Vendor Interoperability: Facilitates equipment interoperability by mandating adherence to widely accepted signalling protocols, thereby reducing integration costs and complexity.
Related Standards
Several standards supplement and integrate with SIST EN 301 989 V1.1.1:2005 to enable robust, interoperable telecommunication solutions:
- EN 300 172: Private Integrated Services Network (PISN); Inter-exchange signalling protocol; Circuit-mode basic services.
- ETS 300 239: PISN; Inter-exchange signalling protocol; Generic functional protocol for the support of supplementary services.
- ETS 300 366: PISN; Inter-exchange signalling protocol; Call completion supplementary services.
- ETS 300 475-1: Private Telecommunication Network (PTN); Reference configuration for PTN exchanges.
- TS 101 905: Guidelines on signalling interworking between QSIG and H.323 for supplementary services.
By adhering to these interconnected standards, organizations can foster greater consistency, reliability, and functionality within their corporate telecommunication environments, delivering seamless communication services regardless of underlying protocol differences.
Keywords: corporate telecommunication networks, QSIG, H.323, signalling interworking, call completion, supplementary services, PISN, private telephony, telecommunication standards, ISO/IEC 21991.