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ITC242 – Introduction to Data
Communications
Week 12
Topic 18
Chapter 19 Network
Management
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Last Week
Network Security
• Describe the most important security threats
faced by distributed data processing
• Compare conventional and public-key
encryption
• Discuss the application of encryption to network
security
• Discuss the use of IPSec to create a virtual
private network
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Topic 18 – Network Management
Learning Objectives
• Describe the key requirements that a
network management system should
satisfy
• Describe an overview of the architecture
and key elements of a network
management system.
• Describe SNMP and the difference
between versions 1,2 and 3
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ISO management Functional Areas
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•
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Fault management
Accounting management
Configuration and name management
Performance management
Security management
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Fault Management
• A fault is an abnormal condition that
requires management attention (or action)
to repair
• A fault is usually indicated by failure to
operate correctly or by excessive errors
• Examples: communication link is
physically cut; no signals can get through
• Users expect quick and reliable resolution
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Responding to Faults
• When faults occur, it is critical to quickly:
– Determine exactly where the fault is
– Isolate the rest of the network from the failure so that
it can continue to function without interference
– Reconfigure or modify the network to minimize the
effect of removing the failed component(s)
– Repair or replace the failed components to restore the
network to its initial state
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User Requirements
for Fault Management
• Tolerant of occasional outages, but expect
speedy resolution
• Requires rapid and reliable fault detection and
diagnostic management functions
• Impact and duration of faults can be
minimized with redundancy
• Good communication with users about outages
and faults is critical
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Accounting Management
Overview:
• Internal charging for the use of network services.
• Also used for monitoring the use of and planning network
services.
User Requirements:
• What information is to be recorded where?
• Privacy considerations.
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Configuration Management
• Concerned with:
– initializing a network and gracefully shutting down part
or all of the network
– maintaining, adding, and updating the relationships
among components and the status of components
themselves during network operation
• Operations on certain components should be able to
be performed unattended
• Network manager needs the capability to change the
connectivity of network components
• Users should be notified of configuration changes
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Performance Management
• What is the level of capacity utilization?
• Is there excessive traffic?
• Has throughput been reduced to unacceptable
levels?
• Are there bottlenecks?
• Is response time increasing?
Network managers need performance statistics to
help them plan, manage, and maintain large
networks
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Security Management
• Concerned with
– generating, distributing, and storing encryption keys
– monitoring and controlling access to networks
– access to all or part of the network management
information
– collection, storage, and examination of audit records
and security logs
• Provides facilities for protection of network resources
and user information
• Network security facilities should be available for
authorized users only
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Network Management Systems
• Collection of tools for network monitoring and
control, integrated in these ways:
– A single user-friendly operator interface for performing
most or all network management tasks
– A minimal amount of separate equipment
• Consists of incremental hardware and software
additions implemented among existing network
components
• Designed to view the entire network as a unified
architecture, and provide regular feedback of status
information to the network control center
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Network Management
System Architecture
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Components of the NMS
• Nodes run the Network Management
Entity (NME) software
• Network control host or manager runs the
Network Management Application (NMA)
• Other nodes are considered agents
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Network Management Entity
• Collection of software contained in each
network node, devoted to the network
management task
• Performs the following tasks:
– Collect statistics on communications and networkrelated activities.
– Store statistics locally
– Respond to commands from the network control
center
– Send messages to network control center when local
conditions undergo a significant change
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Simple Network Management
Protocol (SNMP)
• Originally developed for use as a network
management tool for networks and internetworks
operating TCP/IP.
• A collection of specifications that include the
protocol itself, the definition of a database, and
associated concepts.
• Network Management Model
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–
–
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Management station
Agent
Management information base
Network management protocol
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Simple Network Management
Protocol (SNMP)
•
Management station: a standalone device:
–
a set of management applications: data analysis, faulty
recovery and so on
–
A user interface: monitor and control the network
– A database: network management
– Translate the network manger’s requirements into actual
monitoring and control of remote elements in the network
•
•
•
Agent: key platforms( hosts, bridges, routers) +agent
software
Management information base (MIB): a collection of
objects, which are data variables that represent the aspects
of the managed agent.
Network Management protocol: for linking the
management station and agents
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SNMPv1 Configuration
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Role of SNMPv1
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SNMPv2
• Released in 1992, revised in 1996
• Addressed functional deficiencies in
SNMP
• Accommodates decentralized network
management
• Improves efficiency of data transfer
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Elements of SNMPv2
• Each "player" in the network management system
maintains local database of network management
information (MIB)
• Standard defines information structure and allowable
data types (SMI)
• At least one system must be responsible for network
management; others act as agents
• Information exchanged using simple request/respond
protocol, usually running over UDP
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Structure of Management
Information (SMI)
• Defines framework within which a MIB can be
defined and constructed
– data types that can be stored
– formal technique for defining objects and tables of
objects
– scheme for associating a unique identifier with
each actual object in a system
• Emphasis on simplicity and extensibility
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SNMPv3
• Released in 1998, addressed security
deficiencies in SNMP and SNMPv2
• Does not provide a complete SNMP
capability; defines an overall SNMP
architecture and a set of security
capabilities for use with SNMPv2
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Review
• Key requirements that a network
management system should satisfy
• The architecture and key elements of a
network management system.
• SNMP and the difference between
versions 1,2 and 3
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