SNMP (Simple Network Management Protocol) is a protocol that allows network administrators to manage network devices and diagnose their problems.

SNMP is the most popular and popular protocol for managing, monitoring and controlling network devices such as routers, switches through a public or private network. SNMP is not just a protocol, but a fr_amework to control and monitor multiple network devices. SNMP, with two other closely related protocols, namely SMI and MIB, work in unison to achieve this.

SNMP architecture



SMI, MIB and SNMP protocols



SMI
The SMI protocol is basically used to standardize the different attributes of the ob_jects, such as the ob_ject identifiers, the type of ob_ject and the methods of coding the ob_jects.

• ob_ject identifiers: each SNMP ob_ject has a unique ob_ject identifier. SMI allows ob_ject identifiers to be in the form of a name (for example, iso.org.dod.internet.mgmt.mib-2) or in the form of a number (for example, 1.3.6,1,2,1).


• Types of ob_jects: in terms of ob_ject types, SMI defines both standard and integer types, octet chains, etc. as the specific types of non-standard network, such as the IP address, Timeticks, etc.


• ob_ject coding method: SMI uses the basic coding rules (BER) method consisting of type/label, length and value, to encode ob_jects together with their values, for transmission within SNMP packets.


• SMI does not specify the list of ob_jects for a specific protocol/network entity nor does it specify the type of ob_jects that will be used for a specific network protocol. These aspects are taken care of by MIB.

MIB
The MIBs allow the representation of the parameters of the device in a standard format.

MIBs are nothing more than the actual set of ob_jects supported by a network device, to control and monitor using the SNMP protocol.

These ob_jects are classified and maintained separately in different MIB files. The SNMP agent will maintain a separate MIB file on the network device, for each protocol/entity that can be managed using SNMP (for example, system MIB, chassis MIB, IP MIB, TCP MIB, UDP MIB, ICMP MIB, MIB) of interface etc.).

MIBs are organized in a structure similar to a tree and each MIB variable has a unique ob_ject ID

Each MIB file defines three things, namely:

• List of ob_jects supported for a specific protocol/entity


• Type of each ob_ject


• Hierarchical relationship between all the ob_jects of a given protocol/entity

 

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