SRv6 for Power Grid

Segment Routing over IPv6 (SRv6) has seen increasing deployment in service provider networks, driven by its ability to simplify network operations and improve scalability. SRv6 extends the capabilities of traditional IP routing by enabling flexible path steering, traffic engineering, and network programmability, as specified in existing RFCs such as RFC 8754 and RFC 8986. These features make SRv6 particularly suitable for complex network environments like the power grid, where diverse and critical services need to be supported efficiently. The power grid communication network supports multiple services with varying requirements, including real-time monitoring, substation communication, and control system coordination. The hierarchical network structure, comprising backbone and municipal levels, provides a robust foundation for deploying SRv6 to meet these demands. SRv6's ability aligns well with the needs of power grid services, enabling efficient management of service-level agreements (SLAs) and enhancing network reliability. This document presents the experience of deploying SRv6 in a power grid communication network, covering aspects such as service requirements, network structure, and various deployment scenarios.

The power grid network supports two primary service categories: production dispatch & management and marketing information. These are further divided into voice, data, and video communications, each with specific network requirements to ensure reliable power grid operations

• Voice Communication: Dispatch Calls: Critical voice communications between dispatch centers, power plants, and substations must maintain high availability with the highest priority. • Video Communication: Substation Surveillance: Video data from unmanned substations is crucial for monitoring specific areas in real time. This data requires transmission rates between 384 kbit/s and 8 Mbit/s (commonly 2 Mbit/s), with a transmission delay of ≤250 ms, an error rate not exceeding 10^-5, and availability requirements of 99.9%. • Data Communication: Relay Protection and Safety Automation: Signals for relay protection between high-voltage transmission lines and grid safety devices must be highly reliable and have low, fixed transmission delays, including fast command information and real-time data for safety devices. High reliability and low transmission delay are essential for safety signals, with requirements such as delays below 50. Dispatch Automation Data: Real-time monitoring and control data for grid operation are required. Remote data includes telemetry, signaling, control, and regulation information, with transmission rates ranging from 64 kbit/s to 384 kbit/s, a delay of ≤250 ms, and an error rate of 10^-5.

• Management Information Services: Management information services include financial management, marketing, production planning, human resources management, safety supervision information, and information support systems. • Management Office Services: Management office services cover office communication and information management to meet internal and external enterprise communication needs.

• Energy Metering Data: Transmission methods can include dispatch data networks or dedicated circuits, with a transmission error rate not exceeding 10^-6 and availability requirements of 99.99%. • Trading Data: Spot and futures market data involve substantial data volumes, demanding high transmission accuracy for forecasting and transactions.

Traditional MPLS-based power grid data network could provide secure network isolation and multi-service integration. However, with the growing scale of the grid network and the surge in digital services, MPLS technology faces challenges in meeting requirements of power grid. The main gaps are as follows:

• Limitations of QoS and Traffic Engineering: Although MPLS theoretically supports Quality of Service (QoS) and traffic engineering for bandwidth guarantees, these techniques have limitations. For example MPLS RSVP TE (Traffic Engineering) requires pre-reserving bandwidth at each network node, resulting in a complex deployment process New digital services demand more advanced network assurance technologies to support comprehensive multi-service integration.

• Increased Demand for Address Space and IPv6 Transition: The new power system, driven by renewable energy, requires interaction between diverse sources, network load, and storage, leading to a need for extensive network connectivity. The deployment of intelligent terminals will necessitate a shift to an IPv6 single-stack network, which the current MPLS network does not support. • Limited Traffic Scheduling Flexibility: With the rise of smart substations and video surveillance, network bandwidth demands are increasing. MPLS struggles to balance traffic across multiple paths, resulting in uneven bandwidth utilization and congestion.

The power grid communication network is structured into two levels: backbone and municipal. Each level consists of three layers—core, aggregation, and access—creating a clear network topology that facilitates traffic path determination and adjustment. The core layer of the backbone level adopts a fully meshed network architecture. The aggregation layer routers are connected in a dual-uplink tree topology, linking to the access layer devices, which helps distribute traffic and reduce the load on the core routers. Access layer devices are connected to different aggregation equipment based on service requirements or geographical locations. Key departments such as the headquarters dispatch center, headquarters office area, and data centers are directly connected to the national backbone network. Each municipal network operates as a separate Autonomous System (AS) and also comprises the core, aggregation, and access layers, with dual uplinks to the upper-level network. Most access devices in the municipal networks use either ring topology or dual-uplink tree topology, connecting to substations, power supply bureaus, dispatch centers, and other local facilities. The power grid communication network supports two types of service scenarios based on the scope of business access: intra-domain closed-loop services and inter-domain cross-access services. In the intra-domain scenario, the access network facilitates business activities within a single domain, such as connecting from a power supply station to the municipal data center. This setup is centrally managed within the domain and uses EVPN L3VPN over SRv6 Policy for service delivery. All network elements within the domain are controlled by a unified controller, enabling rapid service provisioning, efficient intra-domain traffic path planning, and traffic optimization. For the inter-domain scenario, where cross-domain business access is required, the network accommodates the transition from traditional MPLS VPN networks by adopting the Option A inter-domain approach. This method helps address synchronization issues during network upgrades and ensures a smooth transition across domains. The entire network is planned under a unified framework set by the power grid corporation, with clearly defined VPN categories across the network. Through segmented deployment of EVPN L3VPN over SRv6 Policy, each segment can be optimized for business traffic.

TBD

This document makes no request of IANA. Note to RFC Editor: this section may be removed on publication as an RFC.