Introduction to SNMP

The Simple Network Management Protocol is designed to be easy to implement and provide a uniform way to access information on various machines. Before we can use it from within Tcl, we need to understand how it works so that we know what is happening when we are running commands and examples.

The SNMP protocol is designed so that the footprint of its services is minimal. This allows devices with limited size of storage and operating memory to use the protocol. SNMP uses the UDP protocol which requires much less resources to handle than TCP. It also uses only one packet for sending a single request or response operation so the protocol itself is stateless.

Each machine that is managed by SNMP has a running application that responds to requests from it, and also other computers. Such an application is called an agent. For UNIX systems, it is usually a daemon working in the background. Many devices with embedded systems have SNMP support included in the system core. In...