LibreQoS Bufferbloat Test
Measure your connection's latency under load
Test Results
Total Bufferbloat Grade
Combined score from all test phases
Individual Phase Grades
Download
Upload
Bidirectional
Your bufferbloat grade shows how much extra latency (delay) your connection adds when under heavy load. Lower latency increase = better grade.
How Your Scores Are Calculated
Latency Measurement: We measure your baseline latency (idle connection), then measure latency again during heavy network load to calculate the increase.
Test Phases:
- Download Phase: Saturates your download bandwidth while measuring latency increase
- Upload Phase: Saturates your upload bandwidth while measuring latency increase
- Bidirectional Phase: Saturates both download and upload simultaneously
Grade Calculation: Based on latency increase in milliseconds:
| Latency Increase | Grade | Description |
|---|---|---|
| < 5 ms | A+ | Excellent - Virtually no bufferbloat |
| 5-30 ms | A | Very Good - Minimal bufferbloat |
| 30-60 ms | B | Good - Moderate bufferbloat |
| 60-200 ms | C | Fair - Noticeable bufferbloat |
| 200-400 ms | D | Poor - Significant bufferbloat |
| ≥ 400 ms | F | Very Poor - Severe bufferbloat |
Total Grade Calculation
Your Total Bufferbloat Grade combines all three test phases with equal weighting (33.33% each). Each letter grade is converted to a numeric value (A+=6, A=5, B=4, C=3, D=2, F=1), averaged, then converted back to a letter grade.
Example: If you get A+ (6), B (4), and A (5), your total = (6+4+5)/3 = 5.0 = A grade overall.
What Each Phase Tests
Download: How much latency increases when downloading large files (simulates streaming, software updates)
Upload: How much latency increases when uploading data (simulates video calls, cloud backups)
Bidirectional: How much latency increases during simultaneous heavy download and upload (simulates real-world mixed usage)
Excellent (0-5ms increase)
Your connection has virtually no bufferbloat! Perfect for video calls, online gaming, and real-time applications. Your connection maintains low latency even under heavy load.
Very Good (5-30ms increase)
Minimal bufferbloat with excellent performance. Great for video calls, streaming, and gaming. You may notice slight delays only during very heavy usage.
Good (30-60ms increase)
Moderate bufferbloat that's generally acceptable. Good for most activities, though you might notice some lag during video calls or gaming when downloading large files.
Fair (60-200ms increase)
Noticeable bufferbloat that affects performance. You'll likely experience lag during video calls, choppy streaming, and delayed responses in online games when your connection is busy.
Poor (200-400ms increase)
Significant bufferbloat causing major performance issues. Video calls will be problematic, streaming may buffer frequently, and online gaming will be frustrating during heavy usage.
Very Poor (400ms+ increase)
Severe bufferbloat making real-time applications nearly unusable. Video calls will drop frequently, streaming will buffer constantly, and online gaming will be extremely laggy when downloading or uploading.
What can I do about bufferbloat? Consider upgrading your router firmware to one with better queue management (like OpenWrt with SQM), or contact your ISP about the issue.
Latency (ms)
| Phase | Median | Average | 25th % | 75th % | 95th % |
|---|
Throughput (Mbps)
| Direction | Median | Average | 75th % |
|---|
Simulates a household with 4 users competing for bandwidth. Limitations: best for connections under 200 Mbps.
Phase 1: Connection speed detection (10s) → Phase 2: Household simulation using detected speed (30s)
Alex
Competitive Gaming
Sarah
Video Conference
Jake
HD Netflix Streaming
Computer
Background
Virtual Household Results
Overall Performance
Overall Grade
Combined performance score
Network Fairness
How well bandwidth was shared
Latency Stability
Consistency under load
Individual User Results
Alex
Minimal lag, consistent ping
Sarah
Call was clear, zero drops or jitter
Jake
Slight buffering due BE congestion
Computer
High delay, low throughput (expected)
Your Virtual Household test simulates multiple users with different internet usage patterns to evaluate your network's performance under realistic load.
Network Fairness
What it measures: How evenly bandwidth is distributed among different users and applications in your household.
How it's calculated: We measure the actual throughput each virtual user receives compared to their target bandwidth needs, then calculate how fairly the available bandwidth is shared using the Jain's Fairness Index formula.
Calculation method:
- Each user has target bandwidth requirements (Gaming: 1.5 Mbps, Video calls: 2.5 Mbps, Streaming: 25 Mbps, Downloads: varies based on detected speed)
- We measure actual throughput achieved by each user during the test
- Fairness score = (sum of throughputs)² / (n × sum of throughputs²) where n = number of users
- Score ranges from 0% (completely unfair) to 100% (perfectly fair)
Latency Stability
What it measures: How consistent response times remain when multiple users are active simultaneously, with emphasis on latency-sensitive applications.
How it's calculated: We continuously measure latency for each user throughout the test and calculate a weighted stability score that prioritizes gaming and video conferencing users.
Updated Calculation Method (Enhanced for Realistic Thresholds):
- Latency is measured every 100ms for each virtual user during the 30-second household simulation
- User-Specific Thresholds (Updated):
- Alex (Gaming): 75ms latency, 30ms jitter threshold
- Sarah (Video Calls): 150ms latency, 30ms jitter threshold (increased from 100ms for realistic expectations)
- Jake (Streaming): 300ms latency, 100ms jitter threshold (increased from 200ms/20ms for better tolerance)
- Computer (Downloads): 5000ms latency, 100ms jitter, 5.0% loss threshold (increased from 200ms/50ms/2.0% for background tasks)
- Weighted Scoring (Updated): Alex: 48%, Sarah: 48%, Jake: 4%, Computer: 0% (prioritizes latency-sensitive users)
- Individual user scores use forgiving penalty system: no penalty within 1.5x threshold, generous grading scale
- Final stability score combines weighted individual performances
Overall Grade Calculation
What it measures: Your overall network performance combining fairness, stability, and individual user experiences with realistic expectations.
How it's calculated: The overall grade uses updated thresholds and more forgiving scoring to reflect real-world performance expectations.
Updated Weighting Formula:
- Network Fairness (40%): How evenly bandwidth is distributed among users
- Latency Stability (30%): Weighted stability prioritizing latency-sensitive users (Alex: 45%, Sarah: 45%, Jake: 10%, Computer: 0%)
- Individual User Performance (30%): Average of all four virtual users' individual grades using enhanced scoring
Enhanced Calculation Steps:
- 1. Calculate Network Fairness percentage using Jain's Fairness Index
- 2. Calculate Latency Stability using weighted user performance with updated thresholds
- 3. Calculate individual user grades with realistic requirements and forgiving penalties:
- Alex (Gaming): 75ms latency, 30ms jitter thresholds with no penalty within 1.5x threshold
- Sarah (Video Calls): 150ms latency, 30ms jitter thresholds (realistic for video conferencing)
- Jake (Streaming): 300ms latency, 100ms jitter thresholds (tolerant for streaming applications)
- Computer (Downloads): 5000ms latency, 100ms jitter, 5.0% loss thresholds (very tolerant for background tasks)
- 4. Apply generous grading scale: A+ ≥95%, A ≥90%, B ≥80%, C ≥70%, D ≥60%, F <60%
- 5. Combine using weighted formula: Overall = (Fairness × 0.4) + (Stability × 0.3) + (User Average × 0.3)
- 6. Convert final percentage to letter grade using standard scale
Computer Safety Check: Computer user performance is flagged if latency exceeds 5000ms (increased from 3000ms for better tolerance of background tasks).
Grade Scale
Excellent (95-100%)
Outstanding network performance. All users get fair bandwidth allocation and latency remains very stable under load.
Very Good (90-94%)
Great network performance with minor variations. Most users get adequate bandwidth with stable latency.
Good (80-89%)
Good network performance with some inequality in bandwidth distribution or latency variations under load.
Fair (70-79%)
Acceptable performance but some users may experience reduced bandwidth or inconsistent latency during peak usage.
Poor (60-69%)
Poor network performance with significant bandwidth inequality or latency instability affecting user experience.
Very Poor (Below 60%)
Very poor network performance. Major bandwidth inequality and latency instability make multi-user scenarios problematic.
What can I do to improve? Consider upgrading your router firmware to one with better Quality of Service (QoS) management, or contact your ISP about implementing Smart Queue Management (SQM).