How to Simulate Packet Loss Using lueur

This How-To guide shows you how to configure Lueur so that a portion of your traffic is lost. You can keep a persistent level of packet loss or schedule it in specific bursts to test how your application handles intermittent unreliability.

Prerequisites

Install lueur

If you haven’t installed lueur yet, follow the installation instructions.
Basic Proxy Setup Be familiar with running lueur run --with-[fault] commands from your terminal.
Check Available Packet Loss Strategies

lueur implements the Multi-State Markov strategy. Familiarize yourself with any advanced settings if needed.

Constant Packet Loss

In this scenario, lueur starts with packet loss enabled throughout the entire proxy run.

Start the proxy with packet loss on ingress from server side
```
lueur run --with-packet-loss 
```

Scheduled Packet Loss Bursts

Start the proxy with packet loss fo
```
lueur run \
  --duration 10m \
  --with-packet-loss \
  --packet-loss-sched "start:5%,duration:20%;start:60%,duration:15%" # (1)!
```
1. At 5% of 10 minutes (the 30-second mark), enable packet loss for 20% (2 minutes total). At 60% of 10 minutes (the 6-minute mark), enable packet loss again for 15% (1.5 minutes).
  
  Timeline: * Minutes 0–0.5: No loss (normal). * Minutes 0.5–2.5: Packet loss enabled (clients see up to some “lost” packets). * Minutes 2.5–6.0: Normal again. * Minutes 6.0–7.5: Packet loss resumes. * Remaining time to minute 10: No loss.

Next Steps

Monitor Application Behavior: Track if clients adapt or retry effectively when some packets vanish.
Combine with Other Faults: For deeper reliability testing, mix packet loss with latency or bandwidth constraints.