Description
Reliable Data Service (RDS) is a service layer capability standardized by 3GPP to meet stringent reliability requirements for data transmission, especially for mission-critical and industrial Internet of Things (IoT) communications. It operates above the transport layer, providing an assurance that application data is delivered successfully from a source to a target destination. The service is designed to function over various underlying transport protocols, including both IP-based and non-IP data delivery (NIDD) mechanisms, making it adaptable to diverse IoT device capabilities and network architectures.
Architecturally, RDS is implemented within the 3GPP Core Network, specifically involving the Service Capability Exposure Function (SCEF) for Non-IP Data Delivery (NIDD) and the User Plane Function (UPF) for IP-based delivery. The service introduces the concept of a Reliable Data Server (RDS), which acts as an endpoint for the reliable service. For NIDD, the SCEF interfaces with the RDS server, while for IP, the UPF may apply specific packet handling. The service utilizes mechanisms such as end-to-end acknowledgments, retransmissions, and potentially packet duplication over multiple paths to achieve its reliability targets, which can be configured per service request.
The service works by establishing a reliable data session context between the requesting entity (e.g., an Application Server (AS) or a User Equipment (UE)) and the RDS server. The requesting entity specifies the required reliability level and other service parameters. During data transfer, the RDS mechanisms monitor delivery success. If an acknowledgment is not received within a specified time, retransmissions are triggered. The service also manages session state, including buffering of data if the UE is unreachable, and provides delivery reports back to the originator. Its role is crucial for applications where data loss is unacceptable, such as remote control of industrial machinery, smart grid protection commands, or vital health telemetry, ensuring the 5G system can support Ultra-Reliable Low-Latency Communication (URLLC) service commitments.
Purpose & Motivation
RDS was created to address the gap in standardized, network-assisted reliable data delivery for critical machine-type communication (MTC) and IoT services. Prior to its introduction, applications requiring high reliability had to implement complex, proprietary end-to-end protocols on top of the best-effort IP service provided by mobile networks. This was inefficient, increased device complexity and power consumption, and could not leverage network intelligence for optimization.
The motivation stemmed from the industry's push towards Industrial IoT (IIoT) and automation, where control commands and sensor data must be delivered with near-perfect certainty. 3GPP's work on Cellular IoT (CIoT) and Critical Communications identified reliability as a key service requirement that the network itself should natively support. RDS provides a standardized, network-agnostic interface for applications to request and obtain guaranteed data delivery, simplifying application development and enabling consistent service quality across different operator networks and device types. It is a key enabler for 5G's vertical industry ambitions, providing a foundational service for URLLC use cases.
Classification
Release Timeline
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (8 CRs across 3 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the primary new introduction for the Reliable Data Service (RDS) was the "Support for Reliable Data Service with PtP SGi Tunneling," which specifies the protocol for establishing peer-to-peer logical links. This addition enables acknowledged and unacknowledged data transfers between the UE and network entities like the SCEF or P-GW over a single PDN connection. The RDS protocol itself, with its frame structure and procedures for port reservation and reliable delivery, was formally defined in this release.
- Support for Reliable Data Service with PtP SGi Tunneling TS 24.250CR0005
In Release 16, the Reliable Data Service (RDS) was extended to support 5GS, requiring updates to its scope, overview, field format, and procedures to operate within a 5G Core network. This included defining a reference model where RDS uses a PDU session identity and QoS Flow Identifier to transfer data to the NEF or UPF, instead of the EPS bearer ID used in 4G. The release also introduced enhancements for dynamic port management, allowing applications to reserve, release, and query port numbers, including their serialization format.
- Enhancing RDS for dynamic port management TS 24.250CR0011
- Updates to Scope for support of RDS in 5GS TS 24.250CR0012
- Updates to Overview for support of RDS in 5GS TS 24.250CR0013
- Updates to field format and procedures for support of RDS in 5GS TS 24.250CR0014
- Reference model for RDS in 5GS TS 24.250CR0023
- Add RDS configuration information TS 29.244CR0392
In Release 17, the RDS function was enhanced with the capability for applications to indicate a serialization format when reserving port numbers. This addition, specified in the Change Request "Support for Indicating Serialization Format in RDS," also allows peer entities to query which serialization format will be used for a given port reservation. This provides greater flexibility and coordination for applications using the Reliable Data Service.
- Support for Indicating Serialization Format in RDS TS 24.250CR0024
Explore further
Broader topics and technologies where RDS plays a role.
Defining Specifications
3GPP specifications that define or reference RDS, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 24.250 vj00 | Reliable Data Service Protocol Specification | Rel-19 |
| TS 29.244 vj40 | PFCP Specification for Control/User Plane Separation | Rel-19 |
| TS 29.541 vj30 | NEF Service-Based Interfaces for NIDD & SMS | Rel-19 |
