Simple Network Management Protocol( SNMP) Part 2

 Basic Commands

Four basic SNMP commands used for monitoring and controlling managed devices include:

1. Read command: It is used by an NMS to monitor managed devices. The NMS examines different variables that are maintained by managed devices.
2. Write command: It is used by an NMS to control managed devices. The NMS changes the values of variables stored within managed devices.
3. Trap command: It 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.
4. Traversal operations: These operations are executed by the NMS for determining variables supported by a managed device and to sequentially gather information in variable tables, such as a routing table.

SNMP Management Information Base (MIB)

MIB is a collection of hierarchically organized information which is accessed using a network-management protocol such as SNMP. MIBs include managed objects and are identified by object identifiers.

• A managed object also known as a MIB object, an object, or a MIB consists of one or more object instances, which are essentially variables. Two types of managed objects are:

    Scalar objects which define a single object instance and Tabular objects which define multiple related object instances grouped in MIB tables.

• An object identifier also known as object ID uniquely identifies a managed object in the MIB hierarchy. The MIB hierarchy can be shown as a tree with a nameless root, the levels of which are assigned by different organizations. 

Introduction: Simple Network Management Protocol ( SNMP)