SDDM

SEAL Data Delivery Management

Services →
Introduced in Rel-18

SDDM is the 3GPP service framework within the SEAL ecosystem that provides standardized mechanisms for managing data delivery, including distribution, subscription, and notification, to enable efficient service-to-service communication.

Category
Services
Introduced
Rel-18
Where
Services
Specifications
2 specs
SDDM Description Purpose Related Classification Detected Changes Specifications

Description

SEAL Data Delivery Management (SDDM) is a core functional framework defined within the 3GPP Service Enabler Architecture Layer (SEAL). Its primary role is to orchestrate the reliable and efficient delivery of data between various service enablers and client applications. Architecturally, SDDM operates as a service layer capability, typically hosted within a network operator's domain or a trusted third-party environment. It abstracts the complexities of direct data distribution, providing a standardized API-based interface for data producers to publish information and for data consumers to subscribe to relevant data streams. The framework manages the lifecycle of data delivery sessions, handles subscription authorization, and ensures data is routed to the correct endpoints based on defined policies and subscriber profiles.

At its core, SDDM works by implementing a publish-subscribe (pub/sub) model. Service enablers acting as data sources (SDDM-S servers) register their available data sets with the SDDM framework. Client applications or other enablers (SDDM-C clients) can then discover and subscribe to these data sources. The SDDM system manages these subscriptions, including validation against user profiles and network policies. When new data is published by a source, SDDM is responsible for determining the list of authorized subscribers and initiating the delivery process. This delivery can be push-based (notifications sent immediately) or pull-based (data fetched by the client), depending on the service requirements and client capabilities.

Key components of the SDDM architecture include the SDDM Client (SDDM-C), the SDDM Server (SDDM-S), and the SDDM Management Function. The SDDM-C is the entity that consumes data, initiating subscription requests and processing received data or notifications. The SDDM-S is the entity that produces and publishes data, making it available for subscription. The SDDM Management Function, potentially distributed, handles the central coordination, including subscription management, routing, policy enforcement, and potentially brokering between multiple clients and servers. Its role in the network is to facilitate a decoupled, scalable, and efficient service layer where application logic is separated from the underlying data distribution mechanics, accelerating the development and deployment of new vertical services.

Purpose & Motivation

SDDM was created to address the growing need for a standardized, network-native data distribution framework for service enablers in 5G and future networks. Prior to its introduction, service layer applications and enablers often relied on proprietary or non-standardized point-to-point integrations for sharing data, leading to complex integrations, vendor lock-in, and inefficient use of network resources. The proliferation of Internet of Things (IoT), edge computing, and network exposure APIs highlighted the limitations of these ad-hoc approaches, particularly for real-time, policy-driven data delivery scenarios.

The primary problem SDDM solves is the lack of a unified mechanism for service-to-service data delivery within the 3GPP ecosystem. It enables a clean separation between service logic (the 'what') and data delivery mechanics (the 'how'). This allows service developers to focus on application functionality while relying on the network to handle reliable, secure, and efficient data distribution. It is motivated by the vision of the SEAL architecture, which aims to provide a common set of reusable service enablers (like group management, configuration management, and data delivery) to accelerate the creation of vertical applications for areas like V2X, industrial IoT, and public safety.

Historically, similar capabilities were either embedded within monolithic service platforms or implemented using generic web technologies without network awareness. SDDM's creation within 3GPP standards ensures it is optimized for telecom environments, with built-in support for network identities (like SUPI), QoS policies, mobility events, and integration with other 3GPP core network functions. This provides a level of reliability, security, and context-awareness that external, over-the-top solutions cannot easily match.

Classification

Part ofSEAL
Specific typesSDDM-CSDDM-S
Related approachesCAPIF

Release Timeline

Detected Changes Across Releases

from 3GPP Change Requests

Specific changes extracted from the „Change history“ tables of 3GPP specifications (10 CRs across 2 releases). Complements the general historical overview above with the evidence-based evolution of this function.

Rel-18 4 changes

In Release 18, the SDDM function formally introduced specific APIs for managing transmission connections, including the **Sdd_RegularTransmissionConnection** API for both the SDDM Client and Server, as well as the **Sdd_URLCCTransmissionConnection** API for the SDDM Client. This release also included a correction to the EstablishmentRequest type when provided by the SDDM-C. These defined APIs enable the SDDM-C and SDDM-S to utilize MSGin5G functionalities for sending SEALDD traffic.

  • CDDL specification for the Sdd_RegularTransmissionConnection API provided by the SDDM-S TS 24.543CR0003
  • CDDL specification for the Sdd_RegularTransmissionConnection API provided by the SDDM-C TS 24.543CR0004
  • CDDL specification for the Sdd_URLCCTransmissionConnection API provided by the SDDM-C TS 24.543CR0005
  • Correction to the EstablishmentRequest type when provided by the SDDM-C TS 24.543CR0008
Rel-19 6 changes

In Release 19, the SDDM function introduced a new **Sdd_URLCCTransmissionConnection API** provided by the SDDM-S, complete with its CDDL specification and media types. The release also included updates and corrections to the existing **Sdd_RegularTransmissionConnection API**, alongside fixes for the SDDM XR transmission connection and related quality management APIs.

  • Introduction of Sdd_URLCCTransmissionConnection API provided by the SDDM-S TS 24.543CR0017
  • CDDL specification and Media types for the Sdd_URLCCTransmissionConnection API provided by the SDDM-S TS 24.543CR0032
  • Updates to the Sdd_RegularTransmissionConnection API provided by the SDDM-S TS 24.543CR0033
  • Correction to the Sdd_RegularTransmissionConnection API provided by the SDDM-S TS 24.543CR0075
  • Corrections to SDDM XR transmission connection TS 24.543CR0115
  • Fixing the SDDM-S Sdd_RegularTransmissionConnection API Sdd_TransmissionQualityMeasurement API and Sdd_TransmissionQualityManagement API - CDDL TS 24.543CR0137

Explore further

Broader topics and technologies where SDDM plays a role.

Defining Specifications

3GPP specifications that define or reference SDDM, with the latest known release. Sourced from the 3GPP document catalog — see methodology.

SpecificationTitleRelease
TS 24.538 vj30 MSGin5G Service Protocol Specification Rel-19
TS 24.543 vj50 SEAL Data Delivery Management Protocol Rel-19
Patrick Zandl

About the author: Patrick Zandl (b. 1974)

Telecommunications specialist, technology journalist (founder of the Mobil server), and developer who has been running since 2025 — the largest Czech-language resource on AI-assisted programming. Formerly Chief Wizard Architect at Prusa3D and head of development for Turris at CZ.NIC; currently a consultant and instructor on AI implementation in companies.