MIB
The principle behind SNMP is simple. Each network device maintains a database of network statistics that can be queried from a remote device. The core database is called the Management Information Base
(MIB).
SNMP Commands(PDU)
Instead of using a large set of commands to control network devices, SNMP uses the MIB database to do all of the work. Each controllable feature of the network device is allocated a record in the database. Controlling the feature is as simple as setting the proper value in the database. This means SNMP only has to worry about retrieving and setting database values, rather than having to interpret lots of individual commands to perform actions on the network device.
Using the MIB database reduces the complexity of the SNMP packets. Each SNMP command is called a protocol data unit
(PDU).
SNMP是Simple Network Management Protocol的缩写，可以用它来管理网络设备。SNMP应用UDP来发送和接收数据。一些网络设备是可网管的，这些设备维护一个自身状态的数据库信息，可以通过SNMP发送请求查询这些信息，或者配置这些信息。