Simple Network Management Protocol

Simple Network Management Protocol

Fig 1: Simple Network Management Protocol

The Simple Network Management Protocol (SNMP) is an approach for managing network-attached devices. The SNMP, which was initially created in 1988, is designed to monitor the status of network components and network items that include software, hardware, link utilization, interface temperatures, processors, memory utilization and more. SNMP operates on all equipment used for private internet access like routers, switches and servers. As a protocol, SNMP almost exclusively operates over the Internet Protocol (IP), typically using port 161 or 161U where 161 is the standard port used by SAP for version 1 of the protocol and 161U is the standard port used by SAP for v2 of the protocol.

What is SNMP?

The SNMP is an open standard that defines how network management applications, such as Hewlett Packard's Network Node Manager (NNM) or Cisco's Integrated NetFlow Monitor (INM), can be integrated into network devices to monitor and control the devices' performance. The SNMP is not a network operating system, nor is it a management application. It is a set of standards for management applications that provide information about the network device. The SNMP uses a management information base (MIB) to store information about the device. This information is shared with management applications. The MIBs that describe a device are contained in an object. A management application can obtain information about a device by accessing the object that describes the device.

MIB

The MIB defines the information that is stored about the device and its operation. The MIB is a database that contains definitions for objects that describe the device and its operation. The MIB defines the SNMP operations that can be performed on the device.

SNMPv1

SNMPv1 is defined in RFC 1157. The SNMPv1 protocol has three different modes of operation:

A Management Information Base (MIB)
A Management Information Tree (MIT)
A Simple Network Management Protocol (SNMP) Agent

SNMPv2

SNMPv2 is defined in RFCs 1912 and 2161.SNMPv2 supports the following three MIBs:

The Management Information Base (MIB)
The Management Information Tree (MIT)
The Simple Network Management Protocol (SNMP) Agent

SNMPv3

The SNMPv3 protocol is designed to provide new capabilities to the SNMP protocol. The new capabilities include:

Improved scalability
Improved security
Improved management of large networks
Improved MIBs
Improved management of large networks
Increased scalability

SNMP Objectives

The SNMP is a protocol for network management. The SNMP has multiple objectives:

To support network management applications that access and control network devices.
To support the transfer of management information about the device.
To define a set of objects that describe the device.
Provide a mechanism for management applications to access and control devices.
Provide a mechanism for management applications to transfer management information about the device.

SNMP Authentication

SNMP authentication is the process of proving that a message was sent by a user with the right authorization. SNMP authentication is performed when the management application receives a message.

Common SNMP Errors

Errors that occur when SNMP operations are performed. The following common errors that can occur when SNMP operations are performed.

Invalid OID: An OID is not valid.
Invalid MIB: An MIB is not valid.
No MIB No: MIB exists.
Unsupported OID: An OID is not supported.
Unsupported MIB: An MIB is not supported.

SNMP Traps

The SNMP Trap is a mechanism that allows a management application to notify another management application that a particular event has occurred. The management application can notify the other management application by sending a trap message. A trap is sent by a management application when a specific event occurs. The management application must specify the SNMP version and the type of trap. The management application must specify the OID that identifies the event that occurred. The OID is an OID that identifies a particular event. There are three types of traps that can be sent by the management application:

An SNMPv1 Trap
An SNMPv2 Trap
An SNMPv3 Trap