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High-Speed Ethernet, BERT & FEC Testing
FDNS provides high-speed Ethernet, BERT and FEC testing from 10 Gbps through to 1.6 Tbps where supported by the project and test platform, covering data centres, optical transport, carrier networks, broadband aggregation and mobile backhaul.
For the relationship between physical fibre certification and transmission testing, read our BERT and high-speed Ethernet testing guide and our Data Centre Interconnect testing guide.
What is high-speed Ethernet, BERT and FEC testing?
High-speed Ethernet testing verifies whether a live or newly commissioned service can carry traffic at the required performance level, not simply whether the interface comes up. BERT introduces a controlled test pattern to detect bit errors, while FEC measurements help show how hard the link is working to correct transmission errors before they become service-affecting.
FDNS combines active-service testing with practical optical-network experience across transport and carrier environments. Before testing, we confirm the intended interface, service rate, optics, FEC mode, frame profile, test points, loopback method and acceptance limits. Results are then interpreted against the actual network path so the client receives meaningful commissioning or diagnostic evidence rather than a standalone instrument export.
What our high-speed Ethernet, BERT and FEC testing service includes
Test-plan and service-boundary definition
FDNS defines the service rate, port references, circuit IDs, test endpoints, loopback location, frame profile, transport boundaries and acceptance limits before testing begins. Clear test boundaries prevent misleading results on complex carrier and data-centre paths.
10G to 1.6Tbps Ethernet performance testing
We test high-speed Ethernet services across 10G, 25G, 40G, 100G, 200G, 400G, 800G and up to 1.6Tbps where supported by the project and equipment. Throughput, latency and frame-loss measurements are aligned to the intended service profile.
Bit error rate testing and error analysis
BERT testing applies a controlled pattern to identify bit errors and service instability across the test path. Results are interpreted alongside optics, transport configuration and loopback position so the client can understand where degradation may be occurring.
FEC verification and corrected-error behaviour
Forward error correction is increasingly important on modern high-speed interfaces. FDNS reviews FEC mode, corrected and uncorrected errors, transceiver behaviour and link margin to distinguish a healthy service from one operating close to failure thresholds.
Carrier, DCI and optical-transport commissioning
Testing can support data-centre interconnect, exchange-to-exchange circuits, mobile backhaul, broadband-provider links and CWDM/DWDM transport services. Each result is tied to the actual service path and acceptance scope.
Native result files and commissioning reports
FDNS records configuration, test duration, frame profile, FEC mode, endpoints and measured performance. Native files and readable reports provide a repeatable commissioning baseline for future troubleshooting, reroutes and upgrades.
Define the exact Ethernet service path before BERT testing starts
FDNS confirms service rate, port references, circuit IDs, optics, frame profile, loopback point and transport boundaries before testing. This ensures throughput, latency, BER and FEC results relate to the correct network segment and are meaningful to the client.
Interpret FEC behaviour and corrected errors as part of link health
On 100G, 400G, 800G and higher-speed links, a service can remain up while FEC is correcting increasing error levels. FDNS reviews corrected and uncorrected errors, transceiver behaviour and FEC mode together so clients can identify a link operating close to its margin.
Measure throughput, latency, frame loss and BER together
No single metric proves service quality. FDNS evaluates throughput, latency, frame loss, bit-error performance and service stability against the agreed acceptance profile, giving a clearer view of how the bearer performs under the intended traffic conditions.
Test DCI, mobile backhaul, carrier and optical transport services
FDNS supports data-centre interconnect, exchange-to-exchange circuits, mobile backhaul, broadband-provider networks and Ethernet carried over CWDM or DWDM. The Ethernet client layer and underlying transport path are considered together while keeping test boundaries clear.
Create a repeatable commissioning baseline for future fault investigation
Endpoints, optics, FEC mode, test duration, frame profile and native result files are recorded so the same service can be retested later. This gives operations teams a useful comparison point after reroutes, upgrades or performance degradation.
How FDNS delivers high-speed Ethernet, BERT and FEC testing
FDNS follows a controlled test process from service definition and equipment preparation through loopback setup, traffic generation, FEC analysis and documented acceptance. The workflow is tailored to interface rate, transport platform, optics, service profile and the specific commissioning or troubleshooting objective.
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1. Define the service rate, test endpoints and acceptance criteria
We confirm the interface speed, circuit references, test boundaries, optics, frame profile, service configuration and required performance limits. This prevents ambiguous results where a multi-layer transport path contains several possible failure domains.
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2. Confirm optics, FEC mode, loopback method and platform settings
Transceiver type, breakout arrangement, FEC mode, loopback location and equipment state are reviewed before traffic testing begins. These details are essential at 100G, 400G, 800G and higher rates where corrected-error behaviour can reveal limited system margin.
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3. Build the test path and validate the physical connection
FDNS establishes the agreed loopback or remote endpoint and confirms link state, optical interfaces and service continuity. Any physical-layer or configuration issue is resolved before formal performance measurements start.
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4. Run throughput, latency, frame-loss and BER tests
Traffic is generated against the agreed test profile and duration, with throughput, latency, frame loss and bit-error performance measured across the defined path. Results are interpreted in the context of the actual service rather than as isolated instrument values.
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5. Analyse FEC behaviour, errors and service stability
FDNS reviews corrected and uncorrected errors, FEC mode, optics and link behaviour to determine whether the service is healthy or operating close to its performance margin. Where abnormal results appear, the likely network layer or segment is identified for further investigation.
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6. Produce traceable commissioning and diagnostic evidence
Native result files, configuration, endpoints, optics, FEC mode and measured performance are documented so the client has a repeatable baseline for commissioning, migration, troubleshooting and future capacity upgrades.
High-speed Ethernet, BERT and FEC test standards and acceptance
FDNS builds high-speed Ethernet test plans around the actual service, interface rate and transport platform. Depending on the requirement, testing can reference appropriate IEEE 802.3 interface behaviour, RFC 2544 or ITU-T Y.1564 style performance methods, client acceptance criteria and equipment-vendor requirements. At 100G, 400G, 800G and higher rates, optics and FEC behaviour are reviewed alongside throughput, latency, frame loss and bit-error performance because a link can remain operational while error correction is consuming increasing margin. Test boundaries, loopbacks, frame profiles, FEC modes and duration are defined before measurement so results remain repeatable. FDNS retains native result files, configuration details and engineering observations to provide a defensible commissioning or fault-investigation baseline.
Where high-speed Ethernet, BERT and FEC testing is used
This testing is used for data-centre interconnect, carrier Ethernet, mobile backhaul, broadband aggregation, exchange-to-exchange circuits, optical transport, PoP connectivity and high-capacity network upgrades. It is particularly valuable where a service crosses several network layers and a simple interface-up check cannot prove the required performance. FDNS adapts the test profile to the service rate, frame behaviour, optics, transport path and agreed acceptance objective.
Common high-speed Ethernet test risks and how FDNS controls them
Common problems include testing the wrong service boundary, incorrect loopback, mismatched FEC mode, unsuitable optics, short test duration, unrealistic frame profiles and reports that omit the configuration needed to reproduce the result. FDNS controls these risks by documenting endpoints, port references, transceivers, frame sizes, traffic profile, FEC state and test duration before formal testing begins. Results are interpreted against the actual transport path so the client receives meaningful evidence rather than an isolated tester export.
How BERT and FEC testing connects with FDNS optical engineering
FDNS can combine Ethernet performance testing with fibre testing, OTDR, optical loss, CD/PMD characterisation, CWDM/DWDM engineering and data-centre interconnect work. This allows physical fibre condition, optical transport and client Ethernet performance to be assessed as related layers, helping identify whether a problem sits in the passive fibre, optics, transport platform or service configuration.
What information is needed to plan a high-speed Ethernet or BERT test?
The brief should define service rate, interface type, endpoints, circuit references, optics, FEC mode, transport platform, loopback method, required frame profile, test duration, service availability window and acceptance limits. FDNS uses these inputs to build a repeatable test plan and confirm whether the scope is commissioning, migration, capacity verification or fault investigation.
Prepare both endpoints and transport boundaries before testing
The work package should identify local and remote ports, loopback ownership, intermediate transport boundaries, access arrangements, optics, breakout configuration and any change-control requirement. Where several carriers or teams are involved, responsibilities are agreed before the test window so valuable time is not lost locating the correct circuit or endpoint.
Agree performance thresholds and reporting before the test window
Throughput, latency, frame loss, BER, FEC behaviour and any service-specific criteria should be agreed before measurement begins. FDNS records the test configuration and provides native results and readable reporting so acceptance is based on defined thresholds and the data can be compared later after reroutes, upgrades or fault events.
Why choose FDNS for high-speed Ethernet, BERT and FEC testing?
FDNS provides high-speed Ethernet, BERT and FEC testing as part of a wider optical acceptance and transmission-assurance capability. Because Ethernet test platforms, interfaces and supported data rates evolve quickly, specialist Ethernet testers are normally hired to match the exact project requirement rather than kept as a fixed in-house platform. Where a client specifies a particular tester or manufacturer, FDNS can source the requested platform. The underlying fibre-testing and characterisation capability remains in-house, allowing the transmission test to be correlated with OTDR, loss, ORL, connector condition, CD/PMD and other optical evidence where required.
High-speed testing informed by real optical transport experience
FDNS understands that Ethernet performance may depend on fibre condition, optics, transport equipment, FEC and service configuration. That wider perspective helps us distinguish an Ethernet problem from an optical or transport-layer issue.
BERT and FEC analysis from 10G to 1.6Tbps
Testing can support 10G, 25G, 40G, 100G, 200G, 400G, 800G and up to 1.6Tbps where the platform and project require it. FEC behaviour is reviewed alongside raw errors and service performance so link margin is understood properly.
Carrier, DCI and mobile-backhaul test experience
Our experience includes data-centre interconnect, exchange and PoP connectivity, mobile backhaul and high-capacity carrier transport. This helps us define realistic test boundaries across multi-layer services rather than testing only the easiest accessible interface.
Repeatable test plans and technically useful reports
FDNS documents endpoints, ports, optics, FEC mode, frame profile, duration and loopback arrangement so the result can be reproduced later. Native files and readable reports provide a meaningful commissioning baseline for operations teams.
Ethernet testing integrated with fibre and optical characterisation
Where required, FDNS can combine BERT/FEC work with OTDR, optical loss testing, CD/PMD and fibre-route verification, helping clients investigate the complete service path rather than testing one network layer in isolation.
Frequently asked questions about high-speed Ethernet, BERT and FEC testing
1. What is BERT testing and why is it used on high-speed Ethernet services?
Bit error rate testing applies a controlled test pattern across a defined service path to identify bit errors and instability. It is used to verify whether high-speed Ethernet and optical transport services can carry traffic reliably at the required rate.
2. What Ethernet speeds can FDNS test?
FDNS can support testing from 10G through 25G, 40G, 100G, 200G, 400G, 800G and up to 1.6Tbps where the project and test platform require it. The exact method depends on interface type, optics, FEC mode and service architecture.
3. What does FEC testing tell you about a high-speed optical link?
Forward error correction can mask increasing physical-layer errors before a service actually fails. Reviewing corrected and uncorrected errors helps show whether the link has healthy margin or is operating close to an instability threshold.
4. Does FDNS test throughput, latency and frame loss as well as BER?
Yes. Depending on scope, FDNS can measure throughput, latency, frame loss, BER and service stability against the agreed test profile. These metrics are more useful when interpreted together rather than treated as isolated results.
5. Can BERT and FEC testing be used on data-centre interconnect and carrier networks?
Yes. Typical applications include DCI, carrier Ethernet, mobile backhaul, broadband aggregation, exchange-to-exchange circuits and Ethernet transported over CWDM or DWDM systems.
6. How does FDNS define the correct test boundary?
We confirm the local and remote endpoints, port references, optics, loopback point, transport platform and service configuration before testing. This ensures the result relates to the correct bearer and avoids testing the wrong layer of a multi-stage service.
7. Can FDNS combine BERT testing with fibre and optical testing?
Yes. FDNS can combine Ethernet performance testing with OTDR, optical loss, CD/PMD and route verification where required, helping determine whether a problem sits in the fibre, optics, transport platform or Ethernet service.
8. What is included in a BERT or high-speed Ethernet test report?
Reports can include endpoints, interface rate, optics, FEC mode, frame profile, test duration, measured performance, native files and exceptions. This creates a repeatable commissioning or fault-investigation baseline.
Related optical and network testing services for high-speed Ethernet
Need to prove a 100G, 400G, 800G or higher-speed service? Speak to FDNS
Send us the interface rate, endpoints, circuit references, optics, FEC mode, transport platform, loopback method, frame profile, test duration and acceptance criteria. FDNS can define and execute the appropriate throughput, latency, frame-loss, BER and FEC test plan, then correlate the result with fibre and optical evidence where needed for commissioning, migration or troubleshooting.
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