Download Business Data Communications and Networking

Business Data
Communications and
Networking, 6th ed.
FitzGerald and Dennis
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Copyright © 1999 John Wiley & Sons, Inc.
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Chapter 11
Network Management
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Objectives of Chapter 11
Become familiar with…
 the network management organization
 end user support
 cost management
 several types of network management
hardware tools
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Objectives of Chapter 11
Understand
 what is required to manage the day-to-day
operation of networks
 configuration management
 performance and fault management
 the role and functions of network
management software
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INTRODUCTION
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Introduction
Network Management: the process of
operating, monitoring, and controlling the
network to ensure that it works as intended
and provides value to its users.
Without a well-planned and designed
network, and a well-organized network
management staff, operating the network
becomes extremely difficult. Unfortunately,
many network managers spend most of
their time firefighting - dealing with
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ORGANIZING THE
NETWORK MANAGEMENT
FUNCTION
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The Shift to LANs and the Web
Since the late 1980’s, there has been an
explosion of microcomputer-based
networks.
Although the management of host-based
mainframe networks will always be
important, the future of network
management lies in the successful
management of the LAN, backbone
network, and Internet resources.
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The Shift to LANs and the Web
Today, the critical issue is the integration of all
organizational networks and applications.
This presents two problems:
• First, technical compatibility of technologies
and protocols
• Second, the cultural differences in personalities
and management styles of network managers.
WAN and mainframe managers prefer more
highly structured and controlled environments
than do LAN and Web managers.
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Integrating LANs, WANs, and
the Web
The key to integrating LANs, WANs, and the
Web into one overall organization network
is for both LAN/Web and WAN managers to
recognize that they no longer have the
power they once had.
The central data communication network
organization should have a written charter
that defines its purpose, operational
philosophy, and long-range goals.
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Integrating Voice and Data
Communications
Another major challenge, the separation of voice
and data worked well over the years, but now
changing communication technologies are
causing enormous pressures to combine these
functions.
There is no perfect solution to the problem of
integration, because it must be handled in a way
unique to each organization.
In communications we are moving from an era
where the computer system is the dominant IT
function to one in which communications networks
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are the dominant IT function.
CONFIGURATION
MANAGEMENT
Managing the network’s hardware
and software configuration and
documenting it.
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Configuring the Network and
Client Computers
One of the most common configuration
activities is adding and deleting user
accounts.
Another common activity is updating the
software on the client computers attached
to the network.
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Configuring the Network and
Client Computers
Electronic software delivery is one solution to
the configuration problems associated with
software updates.
ESD greatly reduces the cost of configuration
management because it eliminates the
need to manually update each and every
client computer.
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Documenting the
Configuration
Configuration documentation includes
information about network hardware,
network software, user and application
profiles, and network documentation.
Network maps must be supplemented by
documentation on each individual network
component.
A similar approach can be used for network
software.
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Documenting the
Configuration
Software documentation can also help in
negotiating site licenses for software.
The third type of documentation is the user
and application profiles, which should be
automatically provided by the network
operating system or outside software
agreements.
In addition, other documentation must be
routinely developed and updated pertaining
to the network (incl. manuals).
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PERFORMANCE and FAULT
MANAGEMENT
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Performance and Fault
Management
Performance management: ensuring the
network is operating as efficiently as
possible.
Fault management: preventing, detecting, and
correcting faults in the network circuits,
hardware, and software.
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Network Monitoring
Most large organizations and many small
ones use network management software to
monitor and control their networks.
In large networks, network monitoring
becomes more important.
The parameters monitored by a network
management system fall into two distinct
categories: physical network statistics and
logical network information.
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Network Monitoring
Physical network parameters include monitoring the
operation of the network;s modems, multiplexers,
circuits linking the various hardware devices, and
any other network device.
Logical network parameters include performance
measurement systems that keep track of user
response times, the volume of traffic on a specific
circuit, the destination of data routed around
various network, and any other indices showing
the level of service provided by the network.
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Failure Control Function
Failure control is handled by the network
support group that is called when anything
goes wrong with the network (help desk).
Failure control requires developing a central
control philosophy for problem reporting
and other user interfaces.
Newer “smart” network devices perform their
functions and record data on the messages
on the messages they process.
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Failure Control Function
Numerous software packages are available
for recording fault information.
Trouble tickets must be kept if a manager
wants do do any type of problem tracking.
Problem tracking allows the network manager
to determine who is responsible for
correcting any outstanding problems.
Problem statistics are an important control
device for the network operators as well as
for vendors.
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Failure Control Function
Problem prioritization helps ensure that critical
problems get priority over less important
ones.
Management reports are required to determine
network availability, product and vendor
reliability and vendor responsiveness.
The purpose of the trouble log is to record
problems that must be corrected and to keep
track of statistics associated with these
problems.
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Problem Resolution
The purpose of testing and problem management is
to establish test and validity criteria and
coordinate the various tests.
Mean time to repair (MTTR) is equal to the mean
time to diagnose plus the mean time to respond
plus the mean time to fix a problem.
MTTRepair = MTTDiagnose + MTTRespond + MTTFix
The mean time between failures (MTBF) indicates
the reliability of a network component.
One important time factor is availability, the
percentage of time the network is available to
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Problem Resolution
The network network operations group use
automated network management software
to gather a daily record of the normal
operations of the network. These data can
be used for predicting future growth
patterns and failures.
Such predictions can be accompanied by
establishing simple quality control charts.
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Problem Resolution
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Problem Resolution
More organizations are beginning to establish
service load agreements with their common
carriers and service providers, which
specifies the type of performance and fault
conditions that the organization will accept.
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END-USER SUPPORT
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End-User Support
Solving whatever problems users encounter
while using the network.
Three types:
• Resolving network problems
• Resolving software problems
• Training
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Resolving problems
Problems stem from three major sources:
• Hardware devices
• A lack of user knowledge
• Software or software compatibility.
There are often several levels to the problem
resolution process.
• Basic help desk
• Specialized skills personnel with experience in
problem areas
• Technical specialists.
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Providing End-User Training
End-user training is an ongoing responsibility
of the network management.
Training is usually conducted through in-class
or one-on-one instruction and through the
documentation and training materials
provided.
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COST MANAGEMENT
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Sources of Costs
The total cost of ownership (TCO) is a
measure of how much it costs per year to
keep one computer operating. Many
studies for TCO indicate it can cost up to
five time the value of the computer to keep
it operational.
Although TCO has been widely accepted, many
organizations disagree with the practice of
including user “waste” time in the measure and
prefer to focus on costing methods that examine
only the direct costs of operating the computer.
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Sources of Costs
Since the largest cost item is personnel time,
the primary focus of cost management lies
in designing networks and developing
policies to reduce personnel time, not
reduce hardware costs.
Network managers often it difficult to manage
their budgets because network grow so
rapidly. Many organizations have
implemented charge-back policies for users
of WANs and mainframe-based network.
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Sources of costs
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Reducing Costs
Five steps to reduce network costs
Develop standard hardware and software
configurations for client computers and servers.
 Automate as much of the network management
function as possible by deploying a solid set of
network management tools.
 Reduce the costs of installing new hardware and
software by working with vendors.
 Centralize help desks.
 Move to thin client architectures.

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NETWORK MANAGEMENT
TOOLS
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Network Management Software
Network management software is designed to
provide automated support for some or all
of the network management functions.
There are three fundamentally different types
of network management software:
• Device management software
• System management software
• Application management software
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Network Management Software
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Network Management Standards
One major problem is ensuring that hardware
devices from different vendors can
understand and respond to the messages
sent by the network management software
of other vendors.
The two most commonly used network
management protocols are:
• Simple Network Management Protocol (SNMP)
• Common Management Interface Protocol
(CMIP)
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Network Management Hardware
Testing is divided into:
• analog testing - the analog side of the modem
• digital testing - digital communications circuits
• protocol testing - procedures, packets and
messages.
Testing hardware includes:
•
•
•
•
Monitors and analyzers
Patch panels
Data recorders
Handheld test sets
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Network Management Hardware
Breakout box - a handheld device that can be plugged
into a modem’s digital side to determine voltage
levels.
Bit-Error Rate Tester (BERT) tests the # of bits in error
divided by the total # of bits received.
Block-Error Rate Tester(BKERT) - calculates the
number of received blocks that contain at least one
bit error divided by the total # of blocks received.
Fiber Identifier - locates a particular nonworking fiber
without interrupting service on a fiber optic network.
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Network Management Hardware
Cable analyzer - checks LAN cabling for signal
continuity, pulse distortion, parity, conductivity,
connectivity, polarity reversals, and excessive
noise on the data stream.
Protocol Analyzer - decodes messages on the
circuit to allow you to see the content of a frame
or packet during its transmission.
Data Line Monitor - traces network activity and
response time analysis on a specific circuit, and
checks the actual data.
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Network Management Hardware
Automated test equipment - hardware and
specialized software packages to perform
diagnostic testing, polling, statistics
gathering, protocol emulation,
measurement of bandwidth efficiency, self
diagnosis, analog and digital circuit testing,
testing of centralized and remote switches,
and automatic restart and recovery in case
of disaster.
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End of Chapter 11
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