Why Hitless Failover Matters
Definition: Hitless IP/MPLS failover is a networking redundancy method that replicates data streams across multiple active paths and uses delay compensation to deliver continuous, error-free communication, even if one path fails.
As the energy transition accelerates, utilities face the challenges of integrating renewable energy sources, managing distributed generation, and meeting increasing electrification demands. To ensure uninterrupted, safe, and reliable power delivery, operators must modernize operational communications.
Migrating from aging TDM and SDH networks to IP/MPLS architectures is a critical step – and hitless failover must be at the core to ensure grid protection systems remain stable and resilient.
The Evolving Role of Grid Protection
Grid protection systems, particularly differential line protection, are essential for grid safety. These systems compare current measurements at both ends of a transmission line, instantly detecting faults and isolating them before they escalate into larger outages.
- Protection relays require ultra-reliable, low-latency, time-synchronized communication.
- Legacy SONET/SDH networks provided sub-60 ms switchover with Automatic Protection Switching (APS), but even this delay risked data loss.
- With TDM being phased out, IP/MPLS with hitless failover is the only viable alternative that maintains uninterrupted relay operations.
The Challenge of Network Failover
Conventional IP/MPLS failover methods – like MPLS Fast Reroute (FRR) or active/standby switching – still introduce finite detection and switchover times. These brief disruptions, measured in milliseconds, are unacceptable for differential protection, where even tiny delays can compromise relay performance.
Fact: A momentary gap in communication can cause relays to miss fault signals, leaving transmission lines unprotected.
Introducing Hitless IP/MPLS Failover
Nokia’s innovative hitless IP/MPLS failover solves this problem with an active/active multipath approach combined with asymmetric delay compensation (ADC).
How It Works (H3)
- Protection data is replicated and sent simultaneously across up to four diverse MPLS paths.
- At the receiver, ADC aligns streams, discards duplicates, and forwards valid packets seamlessly.
- If a link or node fails, traffic continues uninterrupted on the remaining paths.
Result: zero packet loss, no switchover delays, and uninterrupted relay protection.
This approach eliminates the need for standby paths or rapid switchovers.
Real-World Validation
Nokia, in collaboration with utilities such as Stedin and partners like Siemens, rigorously tested this solution under multiple scenarios:
- Zero data loss during link and node failures.
- Symmetric delay with minimal jitter, maintaining precise current comparison.
- End-to-end synchronization using IEEE 1588 PTP, SyncE, and clock hierarchies.
- Continuous differential relay operation even during simultaneous path outages.
Result: The solution meets stringent standards for protection systems, proving it can replace legacy TDM without compromising safety.
Comparing MPLS Fast Reroute vs. Hitless Failover
- MPLS Fast Reroute (FRR): Provides alternate paths with sub-50 ms switchover. However, service interruption and packet loss still occur during detection and rerouting.
- Hitless Failover: Maintains multiple active paths in parallel. No switchover occurs, and packets remain continuous even during failures.
For grid protection, where milliseconds matter, FRR is insufficient. Hitless failover is the only approach that guarantees uninterrupted service.
Advantages for Utilities
Unmatched Resilience
Multipath transport with ADC ensures continuous relay operations. Individual link or node failures do not impact protection.
Future-Proof Migration
Transition smoothly from legacy SDH/TDM to IP/MPLS while consolidating multiple services (voice, video, SCADA, teleprotection) on one network.
Enhanced Synchronization and Performance
Integration of PTP and SyncE ensures precise timing, supporting both TDM-based relay interfaces (C37.94) and Ethernet protection protocols.
Lower Complexity and Costs
One IP/MPLS infrastructure simplifies operations and reduces maintenance. Nokia’s Network Services Platform (NSP) provides centralized automation, analytics, and provisioning
Scalability and Flexibility
High-bandwidth MPLS networks support DER management, grid-edge analytics, and wide-area situational awareness, scaling with future grid needs.
The Technology Enablers from Nokia
MCA and Nokia deliver end-to-end solutions for hitless IP/MPLS failover:
- Nokia 7705 SAR and 7210 SAS: Substation and edge aggregation with circuit emulation and Ethernet support.
- Nokia 7750 SR: Core WAN connectivity with advanced MPLS and QoS.
- Nokia 1830 PSS: Ultra-low latency optical backbone transport.
- Nokia Network Services Platform (NSP): Centralized management for IP/MPLS and optical networks, including timing orchestration.
Empowering a Resilient Digital Grid
As utilities advance toward smarter, more sustainable grids, robust and resilient communication infrastructure is no longer optional — it’s mission-critical. Nokia’s hitless IP/MPLS failover delivers the reliability, low latency, and continuous availability that grid protection demands.
With MCA’s deep expertise in utility communications and its trusted partnership with Nokia, utilities can confidently transition to a modern IP/MPLS architecture that not only preserves but enhances grid safety and resilience.
Start Your Journey
Ready to transform your grid communications? Partner with MCA to design and deploy a next-generation IP/MPLS network with hitless failover capabilities. Ensure uninterrupted protection and power the digital utility of tomorrow.
Contact us today to learn more.
Frequently Asked Questions
It is a redundancy method that sends identical data over multiple active MPLS paths and uses delay compensation to ensure continuous, error-free transmission, even during failures.
Differential protection requires uninterrupted, low-latency communication. Even millisecond disruptions can cause relays to miss faults, making hitless failover essential.
Nokia uses multipath pseudowire redundancy with asymmetric delay compensation (ADC) to align streams, eliminate duplicates, and forward uninterrupted packets.
Utilities can replace aging SONET/SDH without sacrificing reliability, while consolidating SCADA, voice, video, and teleprotection on one modern network.
About MCA and Our NIS Team
MCA is one of the largest and most trusted technology integrators in the United States, offering world-class voice, data, and security solutions that enhance the quality, safety, and productivity of customers, operations, and lives. More than 65,000 customers rely on MCA to deliver carefully researched solutions for a safe, secure, and more efficient workplace. As your trusted advisor, we reduce the time and effort required to research, install, and maintain the right technologies to help your organization thrive.
Our nationwide team of certified professionals brings a service-first mindset to every engagement, offering a full suite of reliable technologies backed by expert support throughout the entire solution lifecycle.
Formerly LightSpeed Technologies, Nokia’s #1 VAR and backed by MCA’s sister company, Infinity Technology solutions, Nokia’s #1 Distributor, the Network Infrastructure Solutions (NIS) team brings deep expertise in broadband and critical communications infrastructure. We help our channel partners design and deploy private wireless networks, microwave backhaul, IP/MPLS routing, and optical networking technologies to meet the demands of today’s most complex environments.
