Simple Network Management Protocol
Used for monitoring network devices and encompassing a set of standard protocols. SNMP data contains information describing the network device configuration, and variables describing the state of the device. SNMP can be used to both read and write to the network device, such as reading the configuration and then modifying the configuration. SNMP is most commonly used for monitoring.
Information from network devices may be retrieved via
- GET
- GETNEXT
- GETBULK
Data may be streamed using
- TRAP
- INFORM
Data may be written using
- SET
- The read command is used by an NMS to monitor managed devices. The NMS examines different variables that are maintained by managed devices.
- The write command is used by an NMS to control managed devices. The NMS changes the values of variables stored within managed devices.
- The trap command is used by managed devices to asynchronously report events to the NMS. When certain types of events occur, a managed device sends a trap to the NMS.
SNMP uses the default UDP port 161 for general SNMP messages and UDP port 162 for SNMP trap messages.
Simple Network Management Protocol (SNMP) is a widely used protocol for monitoring the health and welfare of network equipment (eg. routers), computer equipment and even devices like UPSs. Two versions of SNMP exist: SNMP version 1 (SNMPv1) and SNMP version 2 (SNMPv2). Both versions have a number of features in common, but SNMPv2 offers enhancements, such as additional protocol operations. Standardization of yet another version of SNMP—SNMP Version 3 (SNMPv3)—is pending.
Variables accessed by SNMP are organized in hierarchies. These hierarchies, and other metadata, are described by Management Information Bases (MIBs). An SNMP-managed network consists of three key components: managed devices, agents, and network-management systems (NMSs).
SNMP must account for and adjust to incompatibilities between managed devices. Different computers use different data representation techniques, which can compromise the capability of SNMP to exchange information between managed devices. SNMP uses a subset of Abstract Syntax Notation One to accommodate communication between diverse systems.
