Mechanism

The main mechanism used is the Internet Control Message Protocol (ICMP) Echo mechanism, also known as the Ping facility. This allows to send a packet of a user selected length to a remote node and have it echoed back.

Nowadays it usually comes pre-installed on almost all platforms, so there is nothing to install on the clients. The server (i.e. the echo reponder) runs at a high priority (e.g. in the kernel on Unix) and so is more likely to provide a good measure of network performance than a user application.

It is very modest in its network bandwidth requirements (~ 100 bits per second per monitoring-remote-host-pair for the way we use it).

The tools that implement the ping monitoring are collectively known as PingER. There are over 17 Monitoring Sites, over 300 remote sites being monitored and over 1000 monitor-site remote-site pairs included.

What we measure

We use Ping to measure the Response Time, the Packet Loss percentages, the variability of the response time both short term and longer, and the the lack of reachability (no response for a succession of pings). See, for example, PinGER results for Africa.

Following is a short description of each:

Uses of the PingER data

The PingER data for a site can be used in many different ways. Just to name a few:

A detailed technical description of the PingER project, with a list of published papers is available at the PingER homepage.