Chapter 14

Chapter 14Network Management Objectives

Part IV: Network Management

Business Data Communications (6e) Copyright © 2003 by Pearson Education, Inc.

Stamper and Case 14 - 2

Topics Addressed in Chapter 14

• Network management frameworks• Network management objectives• Measuring network effectiveness• Achieving network management objectives• Organizing network management functions• LAN management• WAN management• The Internet’s impact on network management



What is Network Management?

• Network management encompasses a wide range of activities related to network infrastructures in today’s organizations

• Two important network management frameworks exist:– The ISO Management Framework (ISO 7498-4)– ITU-T’s Telecommunications Management

Network (TMN)• Network management can also be classified as being

strategically, tactically, or operationally oriented



ISO 7498-4

• The ISO Management Framework identifies five major categories of network management activities:– Accounting management– Configuration management– Fault management– Performance management– Security management



TMN Framework

• The Telecommunications Management Network (TMN) identifies four functional layers of network management:– Business management– Service management– Network management– Element management



Strategic Network Management

• Strategic network management addresses the long-term role of networks and networking in an organization’s computing infrastructure

• Network planning is an important strategic management activity. Network plans should address:– The incorporation of emerging technologies and applications in the

network infrastructure– Data distribution among enterprise network nodes– Network security enhancements– Proactive mechanisms for addressing network deficiencies– Network staffing and staff development

• Other important strategic network management activities include capacity management, risk management, and contingency planning (including disaster recovery plans)



Tactical Network Management

• Tactical network management includes the translation of strategic network plans to implement plans and timetables. Such plans specify:– The process and timetable to be used to identify network

components.– The process and timetable to be used to select network component

vendors– The specification of cable runs and network component locations– Network component installation and testing timetables

• Other important tactical network management activities include:– Asset management– Service level management – Change management



Operational Network Management

• Operational network management is focused on managing the day-to-day operations of installed networks

• Examples of operational network management activities include:– Troubleshooting and incident management– Managing users– Adding/replacing network hardware– Installing/upgrading software– Performing network backups– Monitoring and maintaining network security.

• Additional operational network management tasks are identified in Table 14-1



Table 14-1



Network Management Objectives

• Several requirements must be met for a network to be viewed positively by users:– Adequate performance

• Response times and throughput are especially important– Consistency – Flexibility– Availability– Reliability– Recovery– Security

• Supporting users also involves keeping them informed, especially about scheduled downtimes, imminent downtime, and other changes that are likely to affect network access and performance



Measures of System Effectiveness

• Key measures of system effectiveness include:– Availability: to users, the network is available when the

components they need are operable and accessible

– Reliability: consistent network availability and consistency across time

– Effectiveness: the degree to which the network serves users’ needs

– Cost-effectiveness: the extent to which the network contributes positively to the organization’s financial position.



Availability• Three key factors influence network uptime/availability:

– Operational considerations (such as scheduled maintenance, upgrades, etc.)

– Mean time between failures (MTBF): the average period of time a network component can be expected to operate before failing

– Mean time to repair (MTTR): the average amount of time needed to place a failed component back in service

• Mathematically: A = MTBF / (MTBF + MTTR) for an individual component

• Table 14-2 and Figure 14-1 illustrate that availability is affected by both MTBF and MTTR

• In general, availability is high when MTBF is high and MTTR is low



Table 14-2



Figure 14-1



Reliability

• Reliability is the probability that a network component will not fail in a given time period. The overall reliability of a network is a function of the reliability of its individual components

• To users, a network’s reliability is correlated with its availability (see Figure 14-2); user perceptions of reliability are also shaped by consistency in response times and network performance

• Fault-tolerant systems which minimize network downtime are likely to be viewed as being reliable by network users



Figure 14-2



Effectiveness

• Overall network effectiveness is a function of the network’s availability and reliability (see Figure 14-3)

• Mathematically: E = A * R• Because both availability and reliability are related

to MTBF and MTTR, network managers should strive to include components with high MTBF and low MTTR

• Fault tolerant networks are likely to be perceived as being effective (as meeting the needs of users)



Figure 14-3



Enhancing Availability and Reliability

• Network managers can enhance network availability and reliability in a number of ways including:– Building fault-tolerance into the system– Incorporating plug-and-play capabilities wherever possible within

the network– Having spare (backup) components on hand so that failed

components can be replaced quickly– Regularly backing up critical files and applications– Ensuring that network support staff are well-trained and have

ready access to troubleshooting tools– Using network monitoring and management tools to alert network

managers of impending component failures



Cost Effectiveness

• The provision of cost-effective solutions to the data communication needs of the organization and its users is another key network management objective– Network managers are charged with selecting solutions that are

feasible and cost-effective– Cost reduction and cost avoidance contribute to cost-effectiveness

• Important aspects of cost-effective network management include:– Effective network planning– Modular expansion– Planned equipment migration (see Figure 14-4)



Figure 14-4



Achieving Network Management Objectives

• Several major factors are likely to contribute to the achievement of network management objectives including a competent staff that:

• Is equipped with the right tools• Has well-defined but flexible direction for short- and long-term• Is willing to work unusual hours in sometimes difficult or stressful

environments• Is able to work effectively with people at all levels of capability• Is skilled in the use of network design and configuration tools• Understands ergonomics• Has appropriate diagnostic and troubleshooting skills• Utilizes effective planning processes• Has access to comprehensive network documentation (see Table 14-3)

• Appreciates the need for standards and procedures



Table 14-3



Organizing Network Management Functions

• Control is a very important aspect of network management

• Network control centers are the focal point of network monitoring and control activities– A network control center is responsible for monitoring

the network and taking corrective actions when necessary

• This may range from a single network application on a network node to a workstation with multiple network monitoring tools, to a “war room” that controls a large enterprise or carrier network



Network Control Center Responsibilities

• Network control center staff are responsible for:– Analyzing data collected by network monitors/agents– Bringing lines and nodes into and out of service– Bringing network applications to an orderly halt and restarting

network applications– Altering network performance parameters– Troubleshooting line outages– Running diagnostic routines– Maintaining the control center database– Maintaining network documentation– Overseeing problem-reporting procedures– Release control



Problem-Reporting Procedures

• Recording problem incidents and their resolution is an important control center function

• Relevant information captured for a problem report includes:– Date and time of the call– Date and time that problem was first observed– Other personnel affected by the problem– Brief detailed description of problem– Is problem reproducible or intermittent?– Possible contributing external influences.

• Help desk and service center software often includes problem-reporting modules



LAN vs. WAN Management

• Managing today’s enterprise networks often requires both WAN and LAN managers (see Figure 14-5). In such networks, WAN managers are responsible for:– Keeping WAN nodes operating properly– Working with carriers to obtain and maintain links between nodes– Maintaining connections between subnetworks– Coordinating the efforts of subnet managers– Managing LAN/WAN interfaces– Administering corporate license agreements– Maintaining the network database– Managing the network control center– Developing network contingency plans– Developing budgeting processes for multiple locations and ensuring

funding for new enterprise-wide infrastructure upgrades



Figure 14-5



LAN Management Tasks

• LAN managers should know data communication fundamentals and how to:

– Connect and disconnect LAN workstations and servers– Diagnose and correct communication medium problems– Add and delete LAN users or shared resources, such as servers– Manage directory services to ensure user access to LAN resources– Implement LAN security (see Table 14-4)– Create, modify, and manage the printing environment– Install and upgrade LAN applications– Perform system backups– Recover from system failures– Maintain LAN documentation and procedures– Assist in setting up LAN interconnections to other networks– Detect and remove viruses



Table 14-4



Managing Network Printing

• Both dedicated and non-dedicated printers are found in network environments (see Figure 14-6). In LANs, network managers:– Map printer ports on workstations to server print queues– Map print queues to one or more printers– Associate printers with one or more print queues– Change print queue and printer port configurations– Assign printer priority schemes– Monitor print jobs routed to particular printers– Start or stop print jobs or printers

– Add or delete printers



Figure 14-6



WAN Management Tasks

• There is considerable overlap between WAN and LAN management responsibilities. Several tasks unique to WAN management include:– Interfacing with carriers and WAN service providers– Estimating WAN equipment and media costs– Configuring WAN components– Resolving international telecommunication problems– Developing and maintaining WAN application software– Coordinating and consolidating network management– Ensuring WAN security



The Internet’s Impact on Network Management

• The Internet and the growing importance of e-business applications have created new network management challenges and opportunities including:

– Ensuring reliable access to business Web sites– Managing commerce servers (and server clusters)– Managing storage area networks (SANs)– Ensuring adequate bandwidth for e-business applications– Managing extranets and interorganizational systems links with business

partners– Maintaining intranets and knowledge management systems– Managing Web-based telework– Supporting wireless Internet applications and mobile commerce

applications– Implementing new security architectures that include firewalls, intrusion

detection systems, virtual private networks (VPNs), and encryption– Ensuring the integrity of Web-based e-commerce transactions

Chapter 14Network Management Objectives

Part IV: Network Management

Chapter 14

Documents

network users

network components

network downtime

network uptimeavailability

network infrastructures

network access

capacity management

risk management