The Simple Network Management Protocol
(SNMP) is an application layer protocol used to
manage network resources. This standardization
gives network administrators the ability to
monitor network performance.
Defines the format of packets exchanged between
a manager and an agent.
It reads and changes the status (values) of
objects(variables) in SNMP packets.
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Here is a very simplified picture.
Network manager contact to the agent through
The agent resides in the managed devices and this
agent have some agent variables which should be
available to this manger for monitoring.
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• A router or host that runs the SNMP server
• Keep the performance information in a data base.
• Can send a trap to the manager if something
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• A host that runs the SNMP client program.
• Has access to values in the agent database.
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A manager checks an agent by requesting
information that reflects the behaviour of the
A manager forces an agent to perform a task by
resetting values in the agent database.
An agent contributes to the management process
by warning the manager of an unusual situation
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This is the actual SNMP protocol itself.
It defines how information is exchanged between
SNMP agents and network management stations.
The SNMP protocol operations define the various
SNMP messages and how they are created and
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SNMP transport mappings describe how SNMP
can be used over various underlying internetworks
such as TCP/IP,IPX and others.
It simply an application program that has a client
on the manager and a server on the agent.
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STRUCTURE OF MANAGEMENT INFORMATION
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SMI defines the general rules for naming objects,
defining object type (including range and length),
showing how to encode object and values.
SMI does not define the number of objects, an
entity should manage or name the objects to be
managed or define the association between the
objects and their values.
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To name objects.
To define the type of data that can be stored in the
To show how to encode the data for transmission.
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MANAGEMENT INFORMATION BASES
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Creates a collection of named objects, their types,
and their relationships to each other in an entity to
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Sequence (like structure)
• Combination of simple data types,not of same
Sequence of (like array)
• Combination of simple data types all of same type.
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STRUCTURED DATA TYPE
Five messages of SNMP
->Sent by manager requesting specific data
2.Get Next Request
->Retrieves the next value of the next lexical
->Agent respond with data for get and set
requests from the manager.
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->Initializes or changes the value of network
->Alarm generated by an agent
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• Traps are unrequested event reports that are sent
to a management system by an SNMP agent
• When a trappable event occurs, a trap message is
generated by the agent and is sent to a trap
destination (a specific, configured network
• Many events can be configured to signal a
trap, like a network cable fault, failing Hard
Drive, a “General Protection Fault”, or a power
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WHAT IS TRAP
• Traps can also be throttled -- You can limit the
number of traps sent per second from the agent
• Traps have a priority associated with them --
Critical, Major, Minor, Warning, Marginal,
Informational, Normal, Unknown
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WHAT IS TRAP
(0).coldStart -agent has been booted
(1).warmStart -agent has been rebooted
(2).linkDown -interface has gone down
(3).Linkup -interface has come up
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4.authenticationFailure -invalid community
5.egpNeighbourLoss -router has gone to down state
6.enterpriseSpecific -other messages
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COMMERCIAL SNMP APPLICATIONS
Here are some of the various SNMP Management products available today
•http://www.hp.com/go/openview/ HP OpenView
•http://www.tivoli.com/ IBM NetView
•http://www.novell.com/products/managewise/ Novell ManageWise
•http://www.sun.com/solstice/ Sun MicroSystems Solstice
•http://www.microsoft.com/smsmgmt/ Microsoft SMS Server
•http://www.compaq.com/products/servers/management/ Compaq Insight Manger
•http://www.redpt.com/ SnmpQL - ODBC Compliant
•http://www.empiretech.com/ Empire Technologies
•ftp://ftp.cinco.com/users/cinco/demo/ Cinco Networks NetXray
•http://www.netinst.com/html/snmp.html SNMP Collector (Win9X/NT)
•http://www.gordian.com/products_technologies/snmp.html Gordian’s SNMP Agent
•http://www.castlerock.com/ Castle Rock Computing
•http://www.adventnet.com/ Advent Network Management
•http://www.smplsft.com/ SimpleAgent, SimpleTester
Allows distributed management access
Light weight protocol
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ADVANTAGES OF USING SNMP
TCP/IP protocol suite by Behrouz A. Forouzan.
Internetworking with TCP/IP,principles,protocols
and architectures by Douglas E. Comer.
Network management principles and practices by
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