Traffic Graphing with ``mrtg''

 One example for a web-based network monitoring solution is `` mrtg'' (Multi Router Traffic Grapher), a rather small program written in Perl [21] and C by Tobias Oetiker. The author has made this program available within the public domain, and therefore it is already widely in use. It can partly replace functionality for which it was earlier necessary to buy expensive network management solutions like HP's ``OpenView''.

The program itself consists of two parts. A first program is called in regular intervals and queries a set of SNMP variables. Those values are stored in a file on the web server. This file is then processed by a second program and a web page with graphs over the counters is generated. Figure 1.2 shows a screenshot of such a web page generated with ``mrtg''. The program is very easy to install and highly configurable for use with different networking equipment. Since it is available as source code, it is also very easy to extend.

  

Figure 1.2: Web based traffic analysis with mrtg