Overview
IEC 62056-5-3:2017 specifies the DLMS/COSEM application layer used for electricity metering data exchange. It defines the structure, services and protocol behavior for DLMS/COSEM clients and servers, and the rules to build DLMS/COSEM communication profiles. The standard covers application association management (establish/release), data communication services for accessing COSEM interface objects (defined in IEC 62056-6-2) using Logical Name (LN) or Short Name (SN) referencing, APDU encodings and an XML schema for COSEM APDUs. Edition 3.0 (2017) is a technical revision of the previous edition; significant changes are captured in Annex K.
Key topics and technical requirements
- Application layer architecture: ACSE (Association Control Service Element), xDLMS application services, layer management and control state machines.
- Service set: COSEM-OPEN/RELEASE/ABORT, GET, SET, ACTION, ACCESS, Read/Write, DataNotification, EventNotification, InformationReport and general block transfer.
- Protocol specifics: APDU formats and encoding rules, association establishment/release procedures, conformance block negotiation, confirmed/unconfirmed service behavior.
- Addressing and naming: Support for LN and SN referencing, registered COSEM names, and mapping for different communication profiles.
- Information security: Detailed security model including identification/authentication, message protection, security contexts and access rights. Cryptographic topics in the standard include hash functions, symmetric and public-key algorithms (including ECDSA and Galois/Counter Mode references), random number generation, key management, certificates and security suites.
- Profiles and transport mapping: Guidelines and parameters for multiple communication profiles (HDLC, COSEM_on_IP - TCP/UDP/IP, wired/wireless M‑Bus, S‑FSK PLC), SMS short wrapper and gateway protocol.
- Interoperability & diagnostics: Protocol identification service, XML schema for COSEM APDUs, and rules to ensure interconnectivity across vendor implementations.
Applications and users
- Who uses it: Utilities, smart meter manufacturers, AMI/MDM vendors, systems integrators, firmware and protocol developers, test labs and certification bodies implementing or verifying DLMS/COSEM stacks.
- Practical uses: Designing and implementing smart metering communications, secure meter data access and control, integrating meters into utility head-ends, building gateways or protocol converters, and ensuring interoperability across networks and media (IP, PLC, M‑Bus, SMS, HDLC).
Related standards
- IEC 62056-6-2 (COSEM interface object definitions) - directly referenced for object definitions and attributes.
- Other parts of the IEC 62056 / DLMS/COSEM suite covering lower-layer mappings, object models and conformance profiles.
Keywords: IEC 62056-5-3:2017, DLMS/COSEM application layer, electricity metering data exchange, smart metering, ACSE, xDLMS, COSEM APDU, LN SN referencing, COSEM_on_IP, security suites.