There are many ways to monitor devices: netflow, span port, switchport and so on. Today I will explain how to monitor bandwith, CPU, … of routers and switches using SNMP and Cacti. Simple Network Management Protocol (SNMP) is an “Internet-standard protocol for managing devices on IP networks. Devices that typically support SNMP include routers, switches, servers, workstations, printers, modem racks, and more.” It is used mostly in network management systems to monitor network-attached devices for conditions that warrant administrative attention. SNMP is a component of the Internet Protocol Suite as defined by the Internet Engineering Task Force (IETF). It consists [...]

In ”An introduction to SNMP” I have explained how SNMP protocol works and how use it; but what are the softwares that use SNMP to monitor network bandwith? HP Openview, Ciscoworks, MRTG are some examples. In this article I will explain how monitor Cisco Switches/Routers bandwith under a Linux machine using a free open source tool: MRTG. The Multi Router Traffic Grapher (MRTG) is a tool to monitor the traffic load on network links. MRTG generates HTML pages containing PNG images which provide a LIVE visual representation of this traffic. MRTG consists of a Perl script which uses SNMP to read the traffic counters [...]

In a network environment, it is a good practice monitor Cisco devices. One of the most famous protocol to control and manage Cisco devices is SNMP (Simple Network Management Protocol). SNMP exposes management data in the form of variables on the managed systems, which describe the system configuration. These variables can then be queried (and sometimes set) by managing applications. The main features are: The SNMP is an application layer protocol that facilitates the exchange of management information between network devices. It is part of the Transmission Control Protocol/Internet Protocol (TCP/IP) protocol suite. It uses UDP port 161 for the [...]