Additional Information Required For The Packet Transport Network-Resubmit

The communication networks supporting the electric grid are at a critical inflection point. For decades, reliability was built on deterministic, circuit-switched paths carried over TDM, SONET, and SDH. Those systems did what they were supposed to do: move relatively small amounts of highly predictable traffic with rock-solid timing. Many utilities quite reasonably took a “don’t touch it if it works” stance.

While that architecture served its purpose, its viability has expired. Many utilities, recognizing this, have already begun the transition, resulting in complex hybrid networks of old and new technologies. This in-between state, while a necessary step, introduces its own significant risks and operational burdens. The industry is now faced with a push-pull-hybrid mandate: the obsolescence of legacy infrastructure (the push), the functional demands of modernization (the pull), and the inherent complexity of managing the hybrid network itself.

This paper argues that utilities are facing this transition challenge now. On one side, the old platform is collapsing under its own age and economics. On another, grid modernization is pulling the organization toward capabilities that only a packet-based transport network can realistically deliver. Layered on top is the operational drag of running a long-term hybrid of legacy and packet technologies. The conclusion is straightforward: a planned transition through the hybrid phase to a 100% packet-based utility transport network is no longer a “nice modernization project.” Indefinitely operating in a hybrid state is its own form of highrisk, high-cost operation. Achieving a fully converged packet network is, therefore, a foundational necessity for safe, reliable, and cost-effective future grid operations. Every year a utility delays this transition, it is effectively paying premium maintenance.

The Mandate for Change: Why Utilities Must Transition to a 100% Packet Transport Network will cover the following topics:

Part I — Context and Requirements

• ï Industry Drivers and Constraints
• ï Critical Application Profiles and SLAs

Part II — Reference Architectures and Design Patterns

• ï Substation LAN Design for Digital Protection and Automation
• ï WAN/Core Transport Options
• ï Network Timing and Synchronization Strategy
• ï Protection, Teleprotection, and RAS over Packet
• ï Carrier Interoperability and Private Wireless

Part III — Security, Compliance, and Operations

• ï Security Architecture for OT Packet Networks
• ï Compliance Alignment
• ï Observability, Telemetry, and SRE-style Operations

Part IV — Testing, Migration, and Standardization

• ï Test and QA Lab Considerations
• ï Migration Playbook
• ï Standardization of Design
• ï Lessons Learned and Best Practices

Part V — Planning Aids and Appendices

• ï Procurement and Partnering Aids
• ï Templates and Checklists
• ï Glossary and Definitions
• ï Further Reading and Standards Index