Link Simulator

Rust tool for simulating an arbitrary connection between two network endpoints.

Features:

• Any number of simultaneous connections with individual configurations
• Configurable delay per link
• Data mutation based on a fixed bit error rate to simulate space RF links
• Rate control (excess incoming bytes are dropped)
• Efficiency through zero-copy forwarding of all data packets
• Network configuration via config files
• Extensive network performance insight:
  • Received bytes & packets
  • Dropped bytes & packets
  • Forwarded bytes & packets
  • Actual bandwidth
  • Internal buffer occupancy
  • Mutated bits (flips)
• Optional Grafana integration for monitoring

Build Instructions

Install Rust on your system, then simply execute

cargo build --release

in the project's root folder to build the executable and the test programs.

Usage

Run the executable link_simulator (found in /target/release) with a routes configuration file according to the following syntax:

link_simulator [options] <file>

options:
    -i              Print link info on startup
    -s              Print link statistics to stdout
					(only works on terminals with 60+ chars per line)
					(does not work on Windows)
    -gLINK_NAME     Send link statistics to Grafana for specified link
                    (repeat this option if needed)
    -G              Send statistics of all links to Grafana
    -p              Discard packet if bit is flipped

<file> must have the following format:
    link_name address_in address_out bit_error_rate delay_ms max_bandwidth
    ...
    ...
(lines starting with '#' are ignored)
line format:
    link_name:          String (without spaces)
    address_{in/out}:   IPv4:Port
    bit_error_rate:     float (0.0 ... 1.0(
    delay_ms:           integer [ms]
    max_bandwidth:      float [bps]
example:
    Test_route localhost:2000 localhost:2001 1e-5 2000 1000000

an example routes configuration file (routes.config) is provided in the project directory.

Grafana Integration

First, set up InfluxDB and Grafana

• Influx DB must listen for input at UDP 127.0.0.1:8100
• Grafana must be connected to Influx DB and the provided config file must be loaded (/grafana/link_simulator.json)

Testing locally

Terminal window #1:

./target/release/link_test_receiver

Terminal window #2:

./target/release/link_simulator -i routes.config

Terminal window #3:

./target/release/link_test_sender 800

The sender (#3) will continuously send packets over the Test_route link at a rate of 800kbps. The link should indicate the reception and forwarding of packets, a rate and applied bitflips (#2). The receiver (#1) should also indicate received data 2 seconds after starting the sender (configured delay in routes.config).

Test success criteria

Terminate (Ctrl+C) the sender (#3), wait at least 2s (or other configured delay), then terminate the receiver (#1).

• The link should indicate 0 dropped packets, if routes.config was left unchanged
• Sender and receiver sent and received amount of data should match
• Bit flips in link and receiver should match
• Link received and forwarded data amount and packet count should match