SNMP Protocol

Nzavatunga J.Luwawa197671

Topics SNMP Definition SNMP Network Management Basic Components and their

functionalities MIB SNMP Architecture SNMP commands Safety aspects(version) SNMP Application.

Definition Simple Network Management Protocol

(SNMP) is an application–layer protocol defined by the Internet Architecture Board (IAB) in RFC1157 for exchanging management information between network devices such as routers, switches Wireless devices, processors, servers etc.

Basic Components and their functionalities

SNMP consists of

SNMP manager or NMS - Network-Management Systems

Managed devices SNMP agent

SNMP Manager or NMS System responsible for monitoring and control managed

devices .

Allows administrators to view SNMP reading information through Graphics, tables, reports, email alerts, or sending sms.

Is usually installed in a (or more than one) network server used for management operations, which receives information (SNMP packets) of all devices managed by a network.

Examples of NMS include: MRTG, Cacti, Nagios, PRTG, CiscoWorks

Network ManagementSystem SNMP uses the

transport layer UDP (User Datagram Protocol) on ports 161 and 162, to perform communication between the NMS and managed devices.

SNMP Manager’s key functions Queries agents SETs variables in

agents GETS responses

from agents TRAP-Allows the

agent to notify the management station of significant events.

Managed Devices A managed device or the network

element is a part of the network that requires some form of monitoring and management e.g. routers, switches, servers, workstations, printers, UPSs, etc...

SNMP Agent

The agent is a program that is packaged within the network element. Enabling the agent allows it to collect the management information database from the device locally and makes it available to the SNMP manager, when it is queried for. These agents could be standard (e.g. Net-SNMP) or specific to a vendor (e.g. HP insight agent)

SNMP agent’s key functions

Collects management information about its local environment.

Stores and retrieves management information as defined in the MIB.

Signals an event to the manager. Acts as a proxy for some non–SNMP

manageable network node.

Basic SNMP communication Diagram

MIB(Management Information Base)

Management Information Base (MIB) is a collection of Information for managing network element.

The MIBs comprises of managed objects identified by the name Object Identifier (Object ID or OID).

Managed object is one of any number of specific

characteristics of a managed device

Types of managed objects are:

Scalar –defines a single object instance

Tabular-define multiple related object instances that are grouped in MIB tables.

Object identifier (or object ID)

uniquely identifies a managed object in the MIB hierarchy.

The MIB hierarchy can be depicted as a tree with a nameless root, the levels of which are assigned by different organizations.

MIB Tree Hierarchy

SNMP ArchitectureThe SNMP framework consists of

Master Agent-software program running on a device that supports SNMP, for example a router which interacts with a Managed station.

Subagent- are responsible for passing information specific to the Masters Agent.

Management stations-Works as a client in a client / server communication. Performs information requests to managed devices, which can be temporary or through commands at any time.

SNMP Architecture Diagram

Basic commands of SNMP

GET GET NEXT GET BULK SET TRAPS INFORM RESPONSE

SNMP SECURITY

SNMP security Versions

SNMP v1SNMP v2

Both versions are not safe!

SNMP v3

SNMP Application Real time tracking device (sysUpTimeInstance).

Gather information from the interface (ifName, ifDescr, ifSpeed , ifType, ifPhysAddr).

Measurement transfer network (iflnOctets, ifOutOctets) interface.

Querying a remote ARP cache (ipNetToMedia).

Summary

SNMP is a simple protocol with single purpose, Transport management information.

Bibliography

http://www.ti-redes.com/gerenciamento/snmp/intro/

http://pt.wikipedia.org/wiki/Simple_Network_Management_Protocol

http://www.manageengine.com/network-monitoring/what-is-snmp.html

http://www.slidefinder.net/s/snmp/snmp/7250937/p4

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