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INTRODUCTION TO
INTERNET NETWORK
MANAGEMENT
The Fifth Meeting
Table of Contents
Background
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Origins of Internet
Origins of Internet Network Management
Evolution of SNMP
SNMP Standards and RFCs
SNMP Basic Concepts
 Network Management Architecture
 SNMP Protocol Architecture
 Proxies
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Internet Network Management
 Also referred to as SNMP-based Network Management
 Simple Network Management Protocol (SNMP) is often
referred to as the Internet Network Management
Framework which includes
 management architecture
 structure of management information
 management protocol
 plus related concepts...
 Most widely used in computer communication networks
 Internet Engineering Task Force (IETF) is responsible for
SNMP standardization
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Origins of Internet
 ARPANET (formed by US DoD, 1969) connecting four
geographically separated computers in US
 23 computers in ARPANET (1971)
 Computers in UK and Norway were connected (1973)
 TCP/IP protocol suite as ARPANET’s standard protocol (late 70’s)
 TCP/IP as NFSNET’s standard protocol (1984), then replace
ARPANET
 Continued growth throughout the 80’s and 90’s
 currently more than 40,000,000 nodes on the Internet
 Need for the management of rapidly growing Internet!
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Origins of Internet Network Management
 Internet Control Message Protocol (ICMP)
 until late 70’s, e.g., Ping utility
 Simple Gateway Monitoring Protocol (SGMP) - 1987
 High-level Entity Management System (HEMS)
 generalized version of Host Monitoring Protocol (HMP)
 SNMP
 enhanced version of SGMP
 an interim solution
 Common Management Information Protocol (CMIP) over TCP/IP
(CMOT)
 long-term solution
 did not go very far
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What is SNMP?
 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.
 It is a part of (TCP⁄IP) protocol suite. Transmission Control Protocol ⁄
Internet Protocol
 SNMP is one of the widely accepted protocols to manage and monitor
network elements.
 Most of the professional–grade network elements come with bundled
SNMP agent.
 These agents have to be enabled and configured to communicate with
the network management system (NMS).
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SNMP basic components
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SNMP Manager
Managed devices
SNMP agent
Management Information Database Otherwise called as
Management Information Base (MIB)
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SNMP Manager
 A manager or management system is a separate entity that is
responsible to communicate with the SNMP agent
implemented network devices.
 This is typically a computer that is used to run one or more
network management systems.
 SNMP Manager’s key functions
 Queries agents
 Gets responses from agents
 Sets variables in agents
 Acknowledges asynchronous events from agents
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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.
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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.
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Basic SNMP Communication Diagram
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Management Information Database or Management
Information Base (MIB)
 Every SNMP agent maintains an information database describing the
managed device parameters.
 The SNMP manager uses this database to request the agent for specific
information and further translates the information as needed for the
Network Management System (NMS).
 This commonly shared database between the Agent and the Manager is
called Management Information Base (MIB).
 Typically these MIB contains standard set of statistical and control values
defined for hardware nodes on a network.
 MIB files are the set of questions that a SNMP Manager can ask the agent.
 Agent collects these data locally and stores it, as defined in the MIB.
 So, the SNMP Manager should be aware of these standard and private
questions for every type of agent.
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Evolution of SNMP
SNMPv1
 draft came out in 1988 and became full Internet standard in 1990
 most workstations, bridges, routers, switches and hubs are now equipped
with SNMP agent
 many resource MIBs (including systems & applications) have been
defined
RMON (1995)
 Remote Monitoring, extends the SNMPv1 MIB and functions
SNMPv2
 attempted to improve the deficiencies of SNMPv1
 Full Internet Standard
SNMPv3
 internet drafts came out in Feb. 1998, adding security features
 now a full Internet Standard
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Basic commands of SNMP
 GET: The GET operation is a request sent by the manager to the managed
device. It is performed to retrieve one or more values from the managed device.
 GET NEXT: This operation is similar to the GET. The significant difference is that
the GET NEXT operation retrieves the value of the next Object Identifier (OID) in
the MIB tree.
 GET BULK: The GET BULK operation is used to retrieve voluminous (large) data
from large MIB table.
 SET: This operation is used by the managers to modify or assign the value of the
Managed device.
 TRAPS: Unlike the above commands which are initiated from the SNMP
Manager, TRAPS are initiated by the Agents. It is a signal to the SNMP Manager
by the Agent on the occurrence of an event.
 INFORM: This command is similar to the TRAP initiated by the Agent,
additionally INFORM includes confirmation from the SNMP manager on
receiving the message.
 RESPONSE: It is the command used to carry back the value(s) or signal of actions
directed by the SNMP Manager.
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Typical SNMP communication
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GET⁄ GET NEXT⁄ GET BULK⁄ SET
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TRAP
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INFORM
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IETF Standardization Process (RFC2026)
http://www.ietf.org/rfc/rfc2026.txt
 IETF forms a working group (WG) for a specific task
 WG generates one or more internet drafts (ID)
 ID document can follow one of three tracks
• (1) standards track, (2) informational, (3) experimental
Internet documents are published as RFCs
Internet Proposed Standard
Internet Draft Standard
Internet Full Standard
Other status:
 Obsolete: a document that is replaced by an updated version
 Historic: a document that is retired
 The latest status on IETF NM RFCs can be found from
http://wwwsnmp.cs.utwente.nl/ietf/rfcs/rfcbystatus.html
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RFC (REQUEST FOR COMMENTS)
 A Request for Comments (RFC) is a type of publication from
the Internet Engineering Task Force (IETF) and the Internet
Society, the principal technical development and standardssetting bodies for the Internet.
 An RFC is authored by engineers and computer scientists in
the form of a memorandum describing methods, behaviors,
research, or innovations applicable to the working of the
Internet and Internet-connected systems.
 It is submitted either for peer review or simply to convey new
concepts, information, or (occasionally) engineering humor.
 The IETF adopts some of the proposals published as RFCs as
Internet Standards.
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SNMP Protocol RFCs
Description
Published
RFC
Status
SNMPv1 Protocol
Aug. 1988
1067
Obsoleted by 1098
SNMPv1 Protocol (republished)
Apr. 1989
1098
Obsoleted by 1157
SNMPv1 Protocol (republished)
May 1990
1157
Historic
Secure SNMP Protocol
July 1992
1352
Historic
SNMPv2 Protocol Operations
May 1993
1448
Obsoleted by 1905
SNMPv2 Transport Mappings
May 1993
1449
Obsoleted by 1906
SNMPv2 Protocol Operations
Jan. 1996
1905
Draft Standard
Jan. 1996
1906
Draft Standard
(updated)
SNMPv2 Transport Mappings
(updated)
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SNMPv1 Standards
Description
Structure of Identification
of Management
Information for TCP/IPbased Internets (SMI)
Concise MIB Definitions
Management Information
Base for Network
Management of TCP/IPbased Internet: MIB-II
Published
RFC
Status
May 1990
1155
Full Standard
Mar. 1991
1212
Full Standard
Mar. 1991
1213
Full Standard
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SNMP Full Standards
RFC
Title
3418
Management Information Base (MIB) for the Simple Network Management Protocol (SNMP)
3417
Transport Mappings for the Simple Network Management Protocol (SNMP)
3416
Version 2 of the Protocol Operations for the Simple Network Management Protocol (SNMP)
3415
View-based Access Control Model (VACM) for the Simple Network Management Protocol (SNMP)
3414
User-based Security Model (USM) for version 3 of the Simple Network Management Protocol (SNMPv3)
3413
Simple Network Management Protocol (SNMP) Applications
3412
Message Processing and Dispatching for the Simple Network Management Protocol (SNMP)
3411
An Architecture for Describing Simple Network Management Protocol (SNMP) Management Frameworks
2819
Remote Network Monitoring Management Information Base
2580
Conformance Statements for SMIv2
2579
Textual Conventions for SMIv2
2578
Structure of Management Information Version 2 (SMIv2)
1643
Definitions of Managed Objects for the Ethernet-like Interface Types
1213
Management Information Base for Network Management of TCP/IP-based internets:MIB-II
1212
Concise MIB definitions
1155
Structure and identification of management information for TCP/IP-based internets
1065
Structure and identification of management information for TCP/IP-based internets
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SNMP Network Management Architecture
NMS
 The manager resides in Network
Management Station (NMS) while
the agent resides in the managed
Network Node
 The manager requests the agent
to perform Set and Get operations
on the variables in the
Management information Base
(MIB)
 By means of traps the agent
occasionally notifies the manager
about some events related to
network operation
MIB
Specification
Manager
SNMP
SNMP
Agent
Agent
MIB
Networked Node
MIB
Networked Node
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SNMP Protocol Architecture
NMS
Network
Admin
Host
Manager process
SNMP
Agent process
Central
MIB
User processes
SNMP
UDP
FTP, etc
UDP
TCP
IP
IP
Network-dependent
protocols
Network-dependent protocols
Host
Agent process
Router
Agent process
User processes
SNMP
FTP, etc
UDP
TCP
IP
Network-dependent protocols
SNMP
Internetwork
UDP
IP
Network-dependent
protocols
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The Role of SNMP
SNMP NMS
SNMP agent
Management resources
Management application
SNMP managed objects
SetRequest
SetRequest
Application
manages objects
SNMP manager
UDP
SNMP messages
IP
SNMP agent
UDP
IP
Network-dependent protocols
Network-dependent protocols
network or
internet
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SNMP Proxy Agent
Proxy agent
Management station
Manager process
SNMP
Mapping function
UDP
UDP
IP
IP
Network-dependent
protocols
Management
process
Agent process
SNMP
Network-dependent
protocols
Proxied device
Protocol
architecture used
by proxied device
Network-dependent
protocols
Protocol
architecture used
by proxied device
Network-dependent
protocols
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THE DIMENSIONS OF
MANAGEMENT
PRESENTED BY STUDENT
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