ping-analyzer

Design and implementation notes are in: "Marc Donner Engineering Notebook," a private Google document

2017-12-23

What is ping-analyzer all about?

A habit that I have developed over the course of many years of using the Internet is to keep a ping running in a terminal session. It provides me with a simple view of my connection to the Internet. If my ping shows a problem with connectivity from my desktop to some important server outside, say google.com, then I can expect problems with many of my Internet-based activities.

[What is ping? Ping is a program that uses the ICMP ECHO service defined in RFC 792 to repeatedly send messages to a remote system and report back on the success or failure to receive a returned message and, in the case of success, the round trip time. Ping was written in the early 1980s by the late Mike Muuss at the Ballistic Research Laboratory.]

As the Internet has become increasingly commercialized I have had to learn to deal with ISPs with varying levels of technical skill. Typically, the technical support lines at commercial ISPs are usually populated by nontechnical people who are provided with weak diagnostic tools, little understanding of the architecture of networks, and no authority to go beyond a very limited set of responses. And the set of complaints that they are prepared to handle typically do not include subtle failures like intermittent but regulard connectivity loss, routing failures, DNS problems, or other technical errors.

Architectural view and implied requirements

My home network is reasonably complex and I presume that it is similar to that of other technical folks. In particular, it has an internal firewall / router connected to a terminal adapter provided by the ISP. In order to keep an eye on the health of my connectivity I need to ping several addresses all at once:

1 - the external site that is my canary

2 - the internal address of my ISP's terminal adapter

3 - the internal address of my firewall / router

So my design needs to support several things:

a - multiple concurrent ping streams

b - time synchronization. This supports two needs: (1) ability to document to an ISP the date and time of an outage, and (2) the ability to correlate multiple streams of pings.

c - logging of the ping streams for subsequent analysis