---
title: "Flow Generator"
slug: "features-packet-generator-flow"
updated: 2025-06-17T11:29:59Z
published: 2025-06-17T11:29:59Z
canonical: "docs.fmad.io/features-packet-generator-flow"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fmad.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Flow Generator

One the massive benefits of a full line rate PCAP replay feature is, you can generate PCAPs at any speed, upload them to the FMAD Packet Replay Device and then replay them at any speed you required. There are many ways to generate PCAP files for replay, we will use our builtin utility pcap_genflow ( [https://github.com/fmadio/pcap_genflow](https://github.com/fmadio/pcap_genflow) however many other tools such as tcpreplay, iperf3 and others which can output to a PCAP file for upload.

- is to generate the PCAP using various toolchains
- Upload the PCAP into the FMADIO Capture System
- Replay the capture at any speed

## PCAP Generation

Some example using pcap_genflow as follows

### 100Gbps @ 64B Packets, TCP , 1 Billion Unique Flows

Generate 1 billion packets, with 1M unique TCP flows using 64B packets @ 100Gbps

```plaintext
$ ./pcap_genflow --pktcnt 1e9 --pktsize 64 --flowcnt 1e6 --bps 100e9  > flow_1M_64B_100G.pcap
```

### 100Gbps @ 1500B packets, TCP, 1 Million Unique Flows

Generate 100M packets, with 1M unique TCP flows using 1500B packets @ 100Gbp

```plaintext
$ ./pcap_genflow --pktcnt 100e6 --pktsize 1500 --flowcnt 1e6 --bps 100e9  > flow_1M_1500B_100G.pcap
```

### 100Gbps @ IMIX Packet size distribution, TCP, 1 Million Unique Flows

Generate 100M packets, with 1M unique TCP flows using IMIX packet size distribution @ 100Gbps

```plaintext
$ ./pcap_genflow --pktcnt 100e6 --imix --flowcnt 1e6 --bps 100e9  > flow_1M_IMIX_100G.pcap
```

##