Go Responsiveness

In late 2021 and early 2022, researchers at Apple took to heart the internet-wide call for giving users more actionable information about the state of their network connections and proposed a new metric, RPM:

This document specifies the "RPM Test" for measuring responsiveness. It uses common protocols and mechanisms to measure user experience especially when the network is under working conditions. The measurement is expressed as "Round-trips Per Minute" (RPM) and should be included with throughput (up and down) and idle latency as critical indicators of network quality.

Apple wrote and released an implementation of the test in its iOS and macOS operating systems in versions 15 and Monterey, respectively.

The researchers at Apple, in collaboration with others throughout the internet-measurement community, proposed RPM as an IETF RFC.

Independent Implementation

To become a Draft Standard, "at least two independent and interoperable implementation[s]" must exist [RFC2026]. The goal of this implementation of the standard is to satisfy that requirement.

Operation

Requirements

1. Go (tested with version 1.16.6)
2. The source code

Satisfy Requirements

To install Go, follow the excellent documentation online.

To get the source code,

$ git clone https://github.com/network-quality/goresponsiveness.git

For the remainder of the instructions, we will assume that ${RSPVNSS_SOURCE_DIR} is the location of the source code.

Build

From ${RSPVNSS_SOURCE_DIR} grab all the required modules:

$ go mod download

And then build:

$ go build networkQuality.go

That will create an executable in ${RSPVNSS_SOURCE_DIR} named networkQuality.

Run

From ${RSPVNSS_SOURCE_DIR}, running the client is straightforward. Simply

$ ./networkQuality

Without any options, the tool will attempt to contact networkquality.example.com on port 4043 to conduct a measurement. That's likely not what you intended. To find out all the options for configuring the execution of the tool, specify the --help option:

$./networkQuality --help

networkQuality with the -help option will generate the following output:

  -config string
    	name/IP of responsiveness configuration server. (default "networkquality.example.com")
  -debug
    	Enable debugging.
  -path string
    	path on the server to the configuration endpoint. (default "config")
  -port int
    	port number on which to access responsiveness configuration server. (default 4043)
  -profile string
    	Enable client runtime profiling and specify storage location. Disabled by default.
  -ssl-key-file string
    	Store the per-session SSL key files in this file.
  -timeout int
    	Maximum time to spend measuring. (default 20)

To facilitate testing, you may want to use the open-source RPM server available from Apple on GitHub.

You can also test against the Apple infrastructure using:

$ ./networkQuality --config mensura.cdn-apple.com --port 443 --path /api/v1/gm/config

Contributing

We love contributions. Before submitting a patch, format your code with go fmt.

Normally we would recommend that you format your code using golines before submitting, but golines does not appear to be compatible with Go's new generic types.

This README.md will be updated when golines is patched to support Go's new generic types.

You can easily install golines in to your ${GOPATH} with

$ go install github.com/segmentio/golines@latest

References

[RFC2026] https://datatracker.ietf.org/doc/html/rfc2026