LANs to WANs The Complete Management Guide

Chapter 1 - Local Area Networks
Introduction
Local area networks (LANs) were developed in the 1980s, starting with Ethernet and quickly followed by token ring and others. They enable members of an organization to share databases, applications, files, messages, and resources such as servers, printers, and Internet connections. The promised benefits of LANs are often too compelling to ignore: improved productivity, increased flexibility, and cost savings. These benefits sparked the initial move from mainframe-based data centers to a more distributed model of computing, which continues today.

Ethernet
Ethernet is a type of LAN that uses a contention-based method of access to allow computers to share resources, send files, print documents, and transfer messages. The Ethernet LAN originated as a result of the experimental work done by Xerox Corporation at its Palo Alto Research Center (PARC) in the mid-1970s. Much of the original Ethernet design was incorporated into the 802.3 standard adopted in 1980 by the Institute of Electrical and Electronic Engineers (IEEE).
Ethernet is contention-based, meaning that stations compete with each other for access to the network, a process that is controlled by a statistical arbitration scheme. Each station “listens” to the network to determine if it is idle. Upon sensing that no traffic is currently on the line, the station is free to transmit. If the network is already in use, the station backs off and tries again. If multiple stations sense that the network is idle and transmit at the same time, a “collision” occurs and each station backs off to try again at staggered intervals. This media access control scheme is known as carrier sense multiple access with collision detection (CSMA/CD).

10BaseT
The 10BaseT is the IEEE standard for providing 10-Mbps Ethernet performance and functionality over ubiquitously available unshielded twisted-pair (UTP) wiring. This standard is noteworthy in that it specifies a star topology, unlike traditional 10Base2 and 10Base5, which use coaxial cabling arranged in a bus (single cable with closed ends) or ring topology. The star topology, whereby individual segments of cable are attached to a hub, permits centralized network monitoring, which enhances fault isolation and bandwidth management.
Traditionally, Ethernet has relied on coaxial cable with multi-drop connections to a LAN backbone. Repeaters between the segments keep the signal strength at a consistent level across the Ethernet. The key disadvantage of this bus topology is that any disturbance to the continuity of the cable at any point renders the entire LAN inoperable.
On the other hand, the 10BaseT and traditional bus Ethernet LANs have different distance limitations: 10BaseT operates reliably over cable segments not exceeding 100 meters (330 feet), whereas traditional Ethernet LANs using thick coaxial cable operate reliably over segments of up to 500 meters (1,650 feet) in length.
The 10BaseT standard was designed to eliminate the requirement for shielded wiring. It relies on the twists in twisted-pair wire to hold down frequency loss, which, in turn, improves the integrity of the signal. The twists minimize the effects of this loss by canceling high-frequency signal energy to prevent signals from radiating to and corrupting the signal being carried over nearby twisted pairs (cross-talk). Even the individual wire pairs in 25-pair telephone cable are twisted for this purpose.

Fast Ethernet
The 100BaseT is the IEEE standard for providing 100-Mbps Ethernet performance and functionality over ubiquitously available UTP wiring. Like 10BaseT Ethernet, this standard specifies a star topology. The need for 100 Mbps came about as a result of the emergence of data-intensive applications and technologies such as multimedia, groupware, imaging, and the explosive growth of high-performance database software packages on PC platforms.

Also known as Fast Ethernet, 100BaseT uses the same contention-based MAC method—CSMA/CD—that is at the core of IEEE 802.3 Ethernet. The Fast Ethernet MAC specification simply reduces the “bit time”—the time duration of each bit transmitted—by a factor of 10, enabling a 10-fold boost in speed over 10BaseT
Since no protocol translation is required, data can pass between 10BaseT and 100BaseT stations via a hub equipped with a 10/100-Mbps bridge module. Both technologies are also full-duplex capable, meaning that data can be sent and received at the same time. This compatibility enables existing LANs to be inexpensively upgraded to the higher speed as demand warrants.
Gigabit Ethernet
Token Ring
Other LANs
Conclusion

Chapter 2 - LAN Administration
Introduction
The LAN administrator’s main focus is usually on keeping the network operating properly and making sure the needs of users are addressed in a timely manner, including hardware and software upgrades. To meet the needs of all users, the LAN administrator must have appropriate tools to accomplish a number of specific tasks. Many of these tasks can be automated to enable the LAN administrator to take care of multiple networks that may consist of hundreds of servers, desktop computers and peripherals—the configurations of which may change on a daily basis to meet the varying needs of mobile professionals, telecommuters, workgroups, departments, or the organization as a whole. Many of these tools may come bundled with the LAN vendor’s network management system
Whether bundled with other products or used separately, the right tools help the LAN administrator monitor, analyze, and adapt the LAN to changing organizational needs. Console and Agents
The key concepts in LAN administration are the console and agents. The console is the workstation that is set up to view information collected by the agents. The agents are special programs that are designed to retrieve specific information from the network. An application agent, for example, works on each workstation to log application usage. Workstation users are not aware of the agent and it has no effect on the performance of the workstation or the applications running on it. The collected information is organized into data sets and stored in a relational database, where it can be retrieved for viewing on the LAN administrator’s console.
A comprehensive tool set allows the LAN administrator to perform the following main functions:
· View and manipulate network data;
· Automate file distribution;
· Maintain hardware inventory;
· Manage installed software, including application usage;
· Receive notification of network events;
· Establish and manage network printer support;
· Automate network processes, such as backup and virus detection;
· Monitor disk and file usage;
· Create task lists;
· Work with text files;
· Establish and maintain security;
· Manage storage.
Automating Software Distribution
The complexity of managing the distribution and implementation of software at the desktop requires that IT managers make use of automated file distribution tools. By assisting a network administrator with tasks like packaging applications, checking for dependencies, and offering links to event and fault management platforms, these tools reduce installation time, lower costs, and speed problem resolution.
One of these tools is a programmable file distribution agent. It is used to automate the process of distributing files to particular groups or workstations. A file distribution job can be defined as software installations and upgrades, start-up file updates, or file deletions. Using a file distribution agent, these types of changes can be applied to each workstation or group automatically.
The agent can be set up to collect file distribution status information. The network administrator can view this information at the console to determine if files were distributed successfully. The console allows the administrator to review status data, such as which workstations are set up for file distributions, the stations to which files have been distributed, and the number of stations waiting for distributions.
Periodically, a scan is performed on all disk drives to maintain an accurate inventory of software, enforce vendor license agreements, and check for unauthorized copies of software. By tracking software usage, a company can reduce its software acquisition costs, since accurate usage information can be used to determine which applications are run most before deciding on upgrades and how many copies to buy. The network administrator can choose to be notified of the times when users are denied access to particular applications because all available copies are in use. This may identify the need to purchase additional copies of the software or pay an additional license charge to the vendor so more users can access the application simultaneously.
Monitoring File Use
Virus Scanning
Printer Management
Storage Management
To remain productive, network users must have an adequate amount of disk space for storing programs and data. To help the LAN administrator meet user demands, a disk monitor agent is used to report volume capacity and manage disk space use. Having current disk use information helps the LAN administrator make decisions about reallocating resources or purchasing additional drives or servers.
The disk monitor agent scans the server volumes to collect disk use information. Depending on the product selected, one or more of the following categories of information can be collected by a disk monitor agent and displayed at the console:
· Volumes: Date and time data was collected; server name; volumes scanned, capacity; and total space used and available.
· Directories: Date and time data was collected; server volume and directory names; creation date and time; file count; directory size (in bytes); owner name; and groups to which the owner is a member.
· Directory and file owners: Date and time data was collected; server and volume names; owner name; groups to which the owner is a member; total number of files; and total space used (in bytes).
A disk monitor agent provides automatic notification if disk usage reaches a specified level. Notification can be sent to the person responsible for responding to the situation through a console, network, pager, or e-mail message.
The LAN environment, especially those based on UNIX, are not very friendly when it comes to managing data on disks and tapes. In the UNIX environment, when disk space is exhausted or a job needs an archived file, work stops. Local backups are often so time-consuming that operators often do not bother with them, while remote backups tend to clog the network. Furthermore, tapes are not protected against overwrites, which can result in the loss of important data.

A variety of tools are now available to properly manage storage in the UNIX environment, ensuring that files are backed up at the right time and that tapes are properly labeled and write-protected to prevent data loss. On-line, backup, and archive versions of UNIX files can now be tracked, regardless of the medium on which they reside.
Emerging Internet-related businesses are especially challenged, given their skyrocketing data storage requirements, combined with limited capital and human resources. Not only is the procurement of hardware, bandwidth, and management tools costly, but even when experienced IT professionals with storage and networking expertise are found, these things are increasingly expensive and difficult to retain. For these and other reasons, there is a growing movement to outsource storage and associated management requirements to a new class of supplier called the storage service provider (SSP).
An SSP sells storage capacity as a pay-per-use utility. The SSP offers companies the means to store and access data without the expense of buying and maintaining hardware and software. The SSP also performs crucial functions such as easy expansion, data backup and restoration, security, disaster recovery, and capacity planning. The monthly cost of going with an SSP is ostensibly more attractive than establishing an in-house storage infrastructure, which can entail hundreds of thousands of dollars to establish a multisite installation, plus the ongoing cost of staff to manage the operation on a 24/7 basis.
SSPs leverage SAN architectures to establish enterprise-wide networked storage. This widely accepted approach allows data to be delivered across the enterprise from a remote location that is managed by an SSP.
Reporting Bindery Data
Servers on many LANs have a bindery or registry, which is used for security and accounting. It contains the names and passwords of users and groups of users authorized to log in to a particular server or set of servers. It also holds information about other services provided by the server to the client, such as printers, modems, and gateways. On a NetWare LAN, for example, a bindery agent allows the administrator to monitor information stored in the NetWare bindery. The information reported includes the following:
· Server identifiers (names) and type;
· User login IDs and full names;
· User access rights such as read, write, open, create, delete;
· Maximum connections allowed per server;
· Maximum volumes per server.
By tracking this information, the LAN administrator can determine such things as the times of peak use for each server and the login locations of users. The following types of bindery information can be displayed at the NetWare administrator’s console:
· Servers: Identifies each server, server revision and version number, number of connections supported, maximum number of volumes, and system fault tolerance (SFT) and transaction tracking service (TTS) levels.
· Users: Displays user information, such as login status and maximum number of connections and disk space allowed.
· Groups: Lists groups and users on each server.
· Group supervisors: Lists supervisors for groups on each server.
· Trustees: Lists server users, the directory to which the user or group has rights, and the rights assigned to each user.
· Login locations: Lists users restricted to logging in at particular stations and the stations allowed.
Process Scheduling
Console Text Viewer
Tracking Network Activity
Integrated Help Desk
Conclusion

Chapter 3 - LAN Restoration Planning
Introduction
Network Reliability
Network Availability
Recovery Options
Server Restoration Capabilities
Data Protection
Servers on the WAN
Storage Area Networks
Other Considerations
Conclusion

Chapter 4 - Storage Network Management
Introduction
Storage Area Networks
Emerging Role of IP
Storage Virtualization
Testing
Conclusion

Chapter 5 - Managing Bridges, Routers, Gateways
Introduction
Bridges
Routers
Gateways
Conclusion

Chapter 6 - Managing the Wireless Infrastructure
Introduction
Configuration Details
Mobile IP
Spanning Tree Protocol
Performance Monitoring
Applying Filters
Logs
Setting SNMP Traps
Conclusion

Chapter 7 - Managing Voice Systems
Introduction
Historical Perspective
PBX Components
Centralized Versus Distributed Systems
Virtual Networks
Call Detail Reporting
IP PBXs
Wireless PBX Systems
Centrex
Conclusion

Chapter 8 - Managing the TDM Infrastructure
Introduction
Multiplexers
The Backbone Network
Public and Private Network Interoperability
Voice Compression
Data Support
Clear Channel Capability
ISDN
Role of Digital Cross-Connect Systems
Conclusion

Chapter 9 - Managing Link Performance with CSU-DSUs
Introduction
Digital Data Services
CSU Functionality
Carrier Testing Services
User-Controlled Diagnostics
Fractional T1
Integrated Solutions
Integral Protocol Analyzers
SNMP for Management
Disaster Recovery
Service-Level Management
Conclusion

Chapter 10 - Managing High-Speed Packet Networks
Introduction
Frame Relay
Asynchronous Transfer Mode
IP Networks
Conclusion

Chapter 11 - Network Management Systems
Introduction
Management System Evolution
Management in the Wired World
The Mechanics of SNMP
Graphical SNMP Tools
SNMP on Wireless Networks
Telecommunications Management Network
Open Source Management Tools
Conclusion

Chapter 12 - Managing Service Quality
Introduction
Role of ATM
Adding QoS to Frame and IP
Policy-Based QoS Management
Software Solutions
Hardware Solutions
Service Level Agreements
Conclusion

Chapter 13 - Managing Network Security
Introduction
Threat Assessment
Securing the Workplace
Securing the Network
Data Encryption
Virus Protection
Firewalls
Intrusion Detection Systems
Remote Access Security
Policy-Based Security
Network Management System Security
Security Personnel
Security Training
Conclusion

Chapter 14 - Network Planning and Design Tools
Introduction
Network Documentation Tools
Network Design Tools
Network-Specific Tools
Systems Design
Conclusion

Chapter 15 - WAN Restoration Planning
Introduction
Redundant Carrier Systems
Carrier Restoration Services
Fiber Network Restoration
Packet Data Network Recovery
LEC Restoration Services
Competitive Access Providers
T1 Restoration
DDS Dial Backup
Intelligent Calling Systems
Dial Backup Units
Satellite-Based Restoration
LAN Internets
Conclusion

Chapter 16 - Maintenance and Support Services Local Area Networks
Introduction
Do-It-Yourself Approach
Reporting Requirements
Equipment Requirements
Vendor and Carrier Services
Maintenance Firms
Cooperative Maintenance Programs
Cabling Considerations
Operating Systems
Conclusion