Echo Test

A tool for measuring TCP connection latency between hosts.

Purpose

This repository contains a simple client-server setup for testing TCP connection latency between different hosts in cloud environments. It's designed to evaluate performance of long-lived TCP connections across various network scenarios.

Components

• client/echo_client.py: Python client for sending test data and measuring response times
• server/setup-echo-server.sh: Script to set up and run the echo server

Usage

Server Setup

The echo server uses xinetd to provide a simple TCP echo service on port 7.

1. SSH into the target host and clone this repository
2. Run the setup script with root privileges:

cd server
sudo ./setup-echo-server.sh

The script will:

• Install xinetd
• Configure the echo service
• Update the services file if needed
• Configure the firewall (optional)
• Start and enable the xinetd service

Client Usage

The client script sends data to the echo server and measures round-trip time (RTT) with microsecond precision.

python3 client/echo_client.py [host] [port] [options]

Required arguments:

• host: Echo server hostname or IP address
• port: Echo server port (typically 7)

Optional arguments:

• --size SIZE: Size of payload in bytes (default: 64)
• --frequency FREQUENCY: Frequency to send packets in seconds (default: 1.0)
• --count COUNT: Number of packets to send (default: 0, meaning infinite)
• --timeout TIMEOUT: Socket timeout in seconds (default: 5.0)
• --log-dir LOG_DIR: Directory to store log files (default: logs)

Examples

Run a test with default settings to a server at 10.0.0.1:

python3 client/echo_client.py 10.0.0.1 7

Send 100 packets of 1024 bytes at 0.5-second intervals:

python3 client/echo_client.py 10.0.0.1 7 --size 1024 --frequency 0.5 --count 100

Output & Logs

The client generates two output files:

1. A log file with general information (logs/echo_client_TIMESTAMP.log)
2. A CSV file with precise timing data (logs/echo_client_TIMESTAMP_timings.csv)

The CSV contains columns for:

• packet_num: Sequential packet number
• timestamp: Human-readable timestamp
• send_time_ns: Send time in nanoseconds
• receive_time_ns: Receive time in nanoseconds
• rtt_us: Round-trip time in microseconds