SNMP (Simple Network Management Protocol) is a protocol that allows network managers to monitor and control network devices using a set of standardized messages and data structures. SNMP uses a client-server model, where the network manager (client) sends requests to the network device (server) and receives responses. The network device has an SNMP agent that collects and reports the data using a MIB (Management Information Base), which is a hierarchical database of variables that describe the device’s status and configuration. Each variable in the MIB has a unique identifier called an OID (Object Identifier), which is a dot-separated sequence of numbers that follows a tree structure12.
To retrieve a single value in SNMP, you can use two types of requests: GET and GET NEXT. A GET request asks for the value of a specific OID, and the SNMP agent responds with the value if it exists, or an error if it does not. A GET NEXT request asks for the value of the next OID in the MIB tree, and the SNMP agent responds with the value and the OID of the next variable, or an error if there is no next variable. A GET NEXT request can be useful for discovering the OIDs and values of a device, or for iterating over a table of values34.
A GET VALUE request is not a valid SNMP request, and a GET TABLE request is not a single request, but a series of GET NEXT requests that retrieve all the values in a table . References: 1: SNMP Basics, 2: SNMP Tutorial Part 1 – Understanding MIBs and OIDs, 3: SNMP Tutorial Part 2 – SNMP Get, GetNext, GetBulk, 4: SNMP Commands, : SNMP Table Operations, : SNMP Table Retrieval
