Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
IEC TR 63084: Electric Vehicle Charging Infrastructure — Communication Network Architecture
Comprehensive communication architecture for EV charging networks including V2G and roaming
1. Scope and Significance of IEC TR 63084
IEC TR 63084 provides a comprehensive technical report on communication network architectures for electric vehicle (EV) charging infrastructure. As the global EV fleet expands rapidly — exceeding 40 million vehicles in 2025 and projected to surpass 150 million by 2030 — the charging infrastructure must evolve from simple grid-connected power outlets to intelligent, networked systems capable of dynamic load management, bi-directional power flow (vehicle-to-grid, V2G), and seamless roaming across multiple charging network operators. This technical report addresses the communication stack from the EV inlet to the charging station management system (CSMS) and onward to the distribution system operator (DSO) and mobility service providers (MSPs).
The report surveys existing protocols — IEC 61851 (basic signalling), ISO 15118 (PLC-based V2G communication), OCPP (Open Charge Point Protocol), and OICP (Open Intercharge Protocol) — and presents a reference architecture that harmonizes these into a coherent multi-layer communication model. It identifies gaps, particularly in the areas of cybersecurity for distributed charging networks, real-time telemetry for grid balancing, and interoperability between proprietary charging networks across national borders.
IEC TR 63084 emphasises that a typical DC fast-charging session generates approximately 2-5 MB of data across the ISO 15118 handshake, OCPP transaction records, and CSMS logging — a non-trivial data burden for cellular-connected charging stations with limited data plans.
| Communication Interface | Protocol | Data Rate Required | Key Function |
|---|---|---|---|
| EV to EVSE (Inlet) | ISO 15118 / DIN 70121 | 2-100 Mbps (PLC) | V2G handshake, charging schedule, payment |
| EVSE to CSMS | OCPP 1.6 / 2.0.1 | 64-256 kbps (persistent) | Session management, meter data, diagnostics |
| CSMS to DSO | IEC 61850 / IEC 61968 | 256 kbps – 1 Mbps | Grid capacity request, real-time load telemetry |
| CSMS to MSP/Roaming | OICP / eMIP / OCPI | 128-512 kbps | Roaming authorisation, tariff sync, billing |
2. Communication Architecture and Protocol Stack
2.1 Multi-Layer Reference Model
The technical report defines a four-layer communication model: the EV-ECU layer (in-vehicle battery management system communication via CAN or Ethernet), the EV-EVSE link layer (power line communication or PLC based on HomePlug Green PHY as specified in ISO 15118), the EVSE-CSMS WAN layer (typically cellular 4G LTE or 5G with VPN tunnelling), and the CSMS-backend grid layer (wired fibre or DSL with IEC 61850-90-8 mapping for EV integration). The report highlights that the weakest link in current deployments is the WAN layer: many charging stations are installed in underground parking garages with poor cellular reception, necessitating external antennas or alternative backhaul such as LoRaWAN or satellite IoT for remote locations.
Latency requirements differ dramatically by function: V2G power modulation commands require sub-100 ms latency for frequency regulation services, while tariff updates and firmware upgrades tolerate delays of minutes to hours. IEC TR 63084 recommends a quality-of-service (QoS) framework that prioritises real-time control messages over administrative traffic on the same WAN link.
2.2 Cybersecurity Considerations
With thousands of geographically distributed charging stations connected via public cellular networks, the attack surface is substantial. The TR identifies three critical security domains: (1) EV-EVSE link security — ISO 15118-2 specifies TLS 1.2 with ECDSA certificates and the Plug & Charge mechanism for automatic authentication; (2) EVSE-CSMS channel security — OCPP 2.0.1 mandates TLS 1.3 with mutual authentication and signed security event notifications; (3) Backend-to-grid security — IEC 62351 applies to the substation automation protocols exchanged with the DSO. The report strongly recommends hardware security modules (HSMs) or trusted platform modules (TPMs) in charging stations for secure key storage.
A 2024 penetration study of public charging networks found that 34 % of tested stations had default or weak TLS configurations — a risk that IEC TR 63084 specifically addresses through mandatory cipher suite auditing and automated certificate renewal procedures.
3. Engineering Design Insights
3.1 Scalability and Load Management
As charging station deployments scale from tens to thousands of units, the CSMS architecture must transition from centralised to distributed or hierarchical models. The TR recommends a federated architecture where regional charging station clusters are managed by local “charging station area controllers” (CSACs) that buffer telemetry, execute local load-balancing algorithms, and forward aggregated data to the central CSMS. This reduces WAN bandwidth consumption by 60-80 % compared to direct CSMS polling and provides resilience against WAN outages — the CSAC can continue operating charging sessions independently for up to 48 hours.
3.2 Protocol Interoperability Testing
One of the most challenging aspects of multi-vendor charging infrastructure is ensuring that an EV from Manufacturer A can charge at an EVSE from Manufacturer B using a CSMS from Manufacturer C, with roaming via MSP D. IEC TR 63084 dedicates substantial attention to conformance testing and certification programs. The recommended test pyramid includes unit-level protocol conformance (ISO 15151 PICS validation), integration-level interoperability (OCPP 2.0.1 message sequence testing), and end-to-end roaming validation (OICP cross-provider transaction tests).
Major European cross-border roaming platforms (Hubject, Gireve, e-clearing.net) now require OCPP 2.0.1 conformance certification per IEC TR 63084 guidelines, reducing roaming transaction failures from 12 % to under 2 % since 2023.
4. Frequently Asked Questions
Q1: Does IEC TR 63084 cover wireless inductive charging communication?
Yes, it addresses wireless power transfer (WPT) per IEC 61980, where the communication channel uses a separate short-range RF link (2.4 GHz or 5 GHz ISM band) instead of PLC. The same high-level architecture applies, but with additional requirements for foreign object detection (FOD) telemetry and alignment feedback.
Yes, it addresses wireless power transfer (WPT) per IEC 61980, where the communication channel uses a separate short-range RF link (2.4 GHz or 5 GHz ISM band) instead of PLC. The same high-level architecture applies, but with additional requirements for foreign object detection (FOD) telemetry and alignment feedback.
Q2: What is the recommended data retention policy for charging stations?
The TR recommends retaining transaction records locally for at least 180 days as a buffer against WAN failures, with the CSMS serving as the primary long-term storage. Meter data (for billing integrity) must be retained for at least 3 years per most regulatory frameworks.
The TR recommends retaining transaction records locally for at least 180 days as a buffer against WAN failures, with the CSMS serving as the primary long-term storage. Meter data (for billing integrity) must be retained for at least 3 years per most regulatory frameworks.
Q3: How does the report address charging station firmware updates?
OCPP 2.0.1 provides a standardised firmware update management mechanism that the TR endorses: signed firmware images, staged rollouts with canary groups, delta-updates to minimise cellular data usage, and rollback capability on failure.
OCPP 2.0.1 provides a standardised firmware update management mechanism that the TR endorses: signed firmware images, staged rollouts with canary groups, delta-updates to minimise cellular data usage, and rollback capability on failure.
Q4: Is the ISO 15118 “Plug & Charge” feature mandatory per this TR?
Not mandatory, but strongly recommended. The TR notes that Plug & Charge reduces the charging session initiation time from approximately 60 seconds (RFID card + app) to under 5 seconds, significantly improving user experience at high-utilisation public chargers.
Not mandatory, but strongly recommended. The TR notes that Plug & Charge reduces the charging session initiation time from approximately 60 seconds (RFID card + app) to under 5 seconds, significantly improving user experience at high-utilisation public chargers.
