Chapter 19:
Network Management
Business Data Communications, 4e
Network Management
Requirements
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
Fault is usually indicated by failure to operate
correctly or by excessive errors
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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Accounting Management
Reasons for accounting management:
Internal chargebacks on network use
User(s) may be abusing access privileges and burdening
the network at the expense of other users
Users may be making inefficient use of the network, and
the network
The network manager is in a better position to plan for
network growth if user activity is known in sufficient
detail.
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Configuration Management
Concerned with:
initializing a network and grace-fully 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
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Performance Management
Issues of concern to the network manager include:
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
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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
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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
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Network Management System Architecture
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Components of the NMS
All 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 network-related
activities.
Store statistics locally
Respond to commands from the network control center
Send messages to NCC when local conditions undergo a
significant change
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IBM Network Management
Architecture and NetView
Associated with IBM’s Systems Network
Architecture (SNA)
IBM wants to provide the single, unifying
framework into which all other network
management products feed and from which all the
equipment in a user’s network can be controlled
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Network Management Categories
SNA network management is composed of:
Problem management
Change management
Configuration management
Performance and accounting management
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Problem Management
Problem determination
Problem diagnosis
Problem bypass and recovery
Problem resolution
Problem tracking and control
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Change Management
Software change control
Microcode change control
Hardware change control
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Configuration Management
Physical/logical resource identification
Resource relationship identification
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Performance & Accounting
Management
Response-time monitoring
Availability monitoring
Utilization monitoring
Component delay monitoring
Performance tuning
Performance tracking and control
Accounting
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NetView Software
 Control facility
 Status monitor
 Provides the capability to
operate the network.
 Hardware monitor
 collects notifications of failures
or significant events
 Session monitor
 Collects session-related
information on logical
components of the network;
includes measurements of data
on response time, session failure
 Displays status information;
reactivates network resources
following failures
 Help facilities
 Descriptions of fields on
displays, and a systematic
problem-solving facility
 Customization facilities:
 Permits a user to tailor NetView
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Technical Control
Automatic and remote testing and monitoring of the
system, to reduce downtime due to the need to locate
service personnel
Restoring and/or reconfiguring the system upon
failure in real time
Providing network performance and functioning
statistics to facilitate planning and management for
high availability
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Component-Level Technical
Control
Line Monitors
Captures the signal between a host system and the
network
Generally employed only on the network end
Protocol Analyzers
Can also simulate various network components
Can test communication protocols and codes
Typically handles up to layer 3 of the OSI architecture
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Network Technical Control Systems
 Integrate control devices and centralize the control of the network
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Performance Monitoring
After availability, the second most important
characteristic of a network is performance
Performance data must be available in sufficient
detail to be able to assess the bottleneck that is
causing the problem and to plan appropriate
remedial action
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Component-Level Monitoring
Response-time monitors
Measures, displays, and records response time of each
transaction and the average response time
Hardware monitors
Events: Number of occurrences of specific events
Timing: Timing the duration of a specific signal
Software monitors
Gathers and reports statistics on hardware and systems
and applications software activity
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Network Monitoring Systems
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Indicators Reported by
Network Monitors
Service Parameters
Availability
Response Time
Accuracy and Integrity
Efficiency Parameters
Througput
Polling
Utilization
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Simple Network Management
Protocol (SNMP)
Network Management Model
Management station
Management agent
Management information base
Network management protocol
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Role of SNMP
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Protocol Specification
Transmission of a message
Receipt of a message
Variable bindings
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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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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
Provides three important services: authentication,
privacy, and access control
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