Cacti is an open source network graphing application that uses RRDTool – a data logging and graphing system for time series data.
A router, by default, connects two different networks, and therefore it should have at least two distinct network interfaces. This article will use a Cisco 877W ADSL router that uses three interfaces: one for the ADSL connection, one RJ45 Ethernet port and a Wi- Fi connection. What you want to monitor is the ADSL connection. Don’t worry – do not think that you will need to use the ADSL interface to get the desired data; SNMP can ask any one of the three interfaces and get the same ADSL- related monitoring data!