Probes (measurement points)

Probes (also called measurement points (MP)) are Docker containers that are automatically added to the input and output connections points of the tested network service and contain tool, like traffic generators, to stimulate the service during an experiment.

They are configured inside a PED file as follows:

- name: "mp.output"
  connection_point: "ns:output"
  container: "mpeuster/tng-bench-mp"
  cmd_start: ["iperf -s"]
  cmd_stop: "uptime"
  address: "20.0.0.254/24"  # address of the data interface of the MP
- name: "mp.input"
  connection_point: "ns:input"
  container: "mpeuster/tng-bench-mp"
  cmd_start: "iperf -c 20.0.0.254 -t 3"
  cmd_stop: "uptime"
  address: "20.0.0.1/24" 

IMPORTANT: The names "mp.output" and "mp.input" are fixed in the current version of tng-sdk-benchmark.

The container field specifies the image of the Docker container to be used.

A user can also specify fixed network addresses and the start and stop commands to be executed at the beginning / end of an experiment. Those commands can be lists, containing different commands for a series of experiments. The commands are then executed by tng-sdk-benchmark using the Docker API (remotely, if needed) of the test execution machine.

The commands are executed in the following order for each experiment run:

1. mp.output cmd_start
2. mp.input cmd_start
3. (experiment execution, waiting for time_limit specified in PED)
4. mp.input cmd_stop
5. mp.output cmd_stop

The commands are started in the background (non blocking) and their outputs are automatically redirected to logfiles stored within the containers: cmd_start.log and cmd_stop.log.