📊 Executive Summary
+33%
UDP Throughput
FRER Advantage
FRER Advantage
±0%
TCP Throughput
Difference
Difference
~110μs
Latency
(Both Equal)
(Both Equal)
941 Mbps
TCP Baseline
(Identical)
(Identical)
⚖️ Performance Comparison
Control Group No FRER
TCP Throughput
941 Mbps
UDP Zero-Loss
398 Mbps
Avg Latency (1518B)
110.19 μs
P99.9 Latency
244.95 μs
64B Frame Loss
34% loss
FRER Enabled With TSN
TCP Throughput
941.42 Mbps
UDP Zero-Loss
530 Mbps
Avg Latency (1518B)
109.34 μs
P99.9 Latency
262.14 μs
64B Frame Loss
Acceptable
📈 Visual Analysis
UDP Zero-Loss Throughput Comparison
Latency Distribution (1518B Frames)
UDP Loss Rate vs Throughput
📋 Detailed Metrics Comparison
| Metric | Control Group | FRER Enabled | Difference | Winner |
|---|---|---|---|---|
| TCP Throughput (60s) | 941 Mbps | 941.42 Mbps | ±0% | Equal |
| UDP Zero-Loss (1518B) | 398 Mbps | 530 Mbps | +33.2% | FRER |
| Avg Latency (1518B) | 110.19 μs | 109.34 μs | -0.8% | FRER |
| P50 Latency (1518B) | 105.68 μs | 105.10 μs | -0.5% | Equal |
| P99 Latency (1518B) | 181.51 μs | 180.27 μs | -0.7% | Equal |
| P99.9 Latency (1518B) | 244.95 μs | 262.14 μs | +7.0% | Control |
| 64B Frame Throughput | 93.7 Mbps (34% loss) | 20.51 Mbps (zero-loss) | N/A | FRER |
| TCP Retransmits | 0 | 0 | Equal | Equal |
💡 Key Insights & Analysis
🎯 Primary Discovery: TSN Configuration Dominates Performance
- FRER path has properly configured TSN features: Credit-Based Shaper (CBS), Time-Aware Shaper (TAS), priority queuing
- Control path uses standard best-effort Ethernet: No TSN queue management, default buffer sizes
- Small frames fail catastrophically without TSN: 64B frames show 34% loss on control vs acceptable on FRER
- UDP benefits massively from TSN: 33% throughput improvement demonstrates queue management value
✅ What This Proves
- FRER overhead is negligible when compared to benefits of TSN configuration
- TSN queue management is critical for UDP performance in industrial networks
- TCP flow control masks differences - identical 941 Mbps performance
- Latency remains deterministic - ~110 μs regardless of configuration
- Configuration matters more than topology - well-tuned 2-hop outperforms poorly-tuned direct
⚠️ Experimental Limitations
- Confounding variable: Different TSN configurations between control and treatment
- Not a true apples-to-apples comparison - inadvertently tested TSN value, not pure FRER overhead
- Recommendation: Repeat with identical TSN settings to isolate FRER impact
- Future work: Document exact queue parameters, test with TSN disabled on FRER path
🔬 Experimental Methodology
Test Configuration
- Platform: Microchip LAN9668 (Kontron D10)
- FRER Group: 2-hop network with dual-path redundancy + TSN configuration
- Control Group: Direct connection 10.0.100.1 → 10.0.100.2 (no FRER, standard Ethernet)
- Tools: iperf3 3.9, sockperf (ping-pong mode), RFC 2544 methodology
- Test Duration: TCP (10s, 30s, 60s), UDP (10-30s per rate), Latency (60s per frame size)
Control Variables
- ✅ Same hardware platform
- ✅ Same software tools and versions
- ✅ Same test methodology (RFC 2544 binary search)
- ✅ Same test durations
- ❌ Different TSN configurations (confounding factor!)
📁 Raw Data & Documentation
| Category | File | Description |
|---|---|---|
| FRER Data | experimental_data/frer_zero_loss_threshold_data.json |
FRER zero-loss threshold discovery (530 Mbps) |
experimental_data/rfc2544_comprehensive_data.json |
Complete RFC 2544 benchmark results | |
experimental_data/rfc2544_zero_loss.csv |
Zero-loss throughput by frame size | |
experimental_data/latency_measurements.csv |
Latency percentiles (64B-1518B) | |
FRER_Throughput_Limitations_Paper.md |
Academic research paper (6,200+ words) | |
| Control Data | control_group_no_frer/control_group_data.json |
Complete control group results |
control_group_no_frer/control_tcp_baseline.csv |
TCP throughput tests | |
control_group_no_frer/control_udp_1518B_sweep.csv |
UDP sweep (32 data points) | |
control_group_no_frer/control_latency_measurements.csv |
Latency distribution data |