Chapter 12, Administering Change
Chapter 12, Administering Change
Chapter 12, Lesson 1
Documenting a Running Network
1. Documentation
A. Preparing and maintaining network records are essential tasks that will pay off when changes are necessary to a network.
B. Provides information about how the network should look and perform, as well as where to seek help if there are problems.
C. Developed for maintenance, upgrading, and troubleshooting.
D. Documentation should contain:
1. A map of the entire network, including the locations of all hardware and details of the cabling.
2. Server information, including the data on each server and the schedule and locations of backups.
3. Software information, such as licensing and support details.
4. Essential names and telephone numbers for vendors, suppliers, contractors, and other helpful contacts.
5. Copies of all service agreements.
6. A record of all problems, their symptoms and solutions, including dates, contacts, procedures, and results.
E. Should be thorough, well organized, and stored where it is readily available.
2. Establishing a Baseline
A. A baseline is documentation of the network’s normal operating values.
B. Establish a baseline as soon as the network is operational.
C. Update the baseline whenever users, hardware, or software are added to or subtracted from the system.
D. Baseline performance values can identify future needs for network modifications.
E. Understanding how a healthy network functions is as important as knowing how to solve problems after the network has failed.
F. Must be established over time before anything goes wrong.
G. Steps necessary to establish a baseline:
1. Record the model, serial number, and location of the servers, workstations, and routers.
2. Record the warranty information for each device, and note where all such warranty information is stored.
3. Make a copy of important system files such as AUTOEXEC.BAT and CONFIG.SYS, as well as a complete set of system backup tapes.
4. Create a map of the network, noting the approximate distance between the workstations and the server.
5. Documentation of cable runs can facilitate building inspections and help to demonstrate compliance with regulations, such as fire codes, that prescribe rules for cables placed in the plenum area of a building.
H. Helps to establish and identify:
1. Daily network utilization patterns
2. Bottlenecks
3. Heavy usage patterns
4. Different protocol traffic patterns
3. Documenting Network Performance
A. Overview
1. Establish a network performance baseline after verification that all network connections are correct, all hardware is operational, and any necessary system fine-tuning has been accomplished.
2. Network performance includes:
a. Servers
b. Server NICs
c. Cable connections to the NICs
d. Hubs
e. Cable runs
f. Routers
g. RJ-45 wall plates
h. Workstation NICs
3. Tools are available to help administrators document network performance, including network monitors, protocol analyzers, and other utilities.
B. Network Monitors
1. Overview
a. Tool that captures and filters data packets and analyzes network activity.
b. Takes practice to quickly analyze the network performance statistics.
c. Software manufacturers offer network monitors.
2. Protocol Analyzers
a. Tool that keeps track of network statistics.
b. Can capture bad frames and isolate their source.
c. Can be helpful for a company that has a large network with highly trained staff.
d. Can be inexpensive software programs that run on existing networked computers.
e. More advanced and expensive protocol analyzers are special-purpose portable computers that can be connected to any physical portion of the network to better isolate data-transmission problems.
3. Packet Internet Groper (Ping)
a. A TCP/IP utility to test network connections.
b. Works by sending a message to a remote computer.
c. If the remote computer receives the message, it responds with a reply message.
d. Reply message consists of:
(1) Workstation’s IP address
(2) Number of bytes in the message
(3) How long it took to reply in milliseconds (ms)
(4) Length of Time-To-Live (TTL) in seconds
e. The message “Request timed out,” means the remote workstation did not respond before the TTL time expired.
f. Heavy network traffic or physical disconnection in the route to the remote workstation can cause “Request timed out.”
4. Tracert
a. Utility that documents network performance.
b. UNIX equivalent is also called traceroute.
c. Identifies the route and number of hops the packet of data took to arrive to at its destination.
C. Other TCP/IP Software Tools
1. Ipconfig
a. Diagnostic command that displays all current TCP/IP network configuration values.
b. Useful for systems running Dynamic Host Configuration Protocol (DHCP); allows users to determine how DHCP has configured TCP/IP.
2. Winipcfg
a. Windows 95 and Windows 98 troubleshooting utility that enables users to access information about TCP/IP and NIC settings.
b. Displays the following settings for each NIC installed:
(1) Physical address
(2) IP address
(3) Subnet mask
(4) Default gateway settings
3. Netstat
a. Available only if TCP/IP protocol is installed.
b. Utility lists:
(1) Connections and listening ports
(2) Ethernet statistics
(3) Addresses and port numbers
(4) Protocol connections and statistics
(5) Contents of the routing table
4. Nbtstat
a. Available only if TCP/IP protocol is installed.
b. Displays protocol statistics and current TCP/IP connections using NetBIOS over TCP/IP.
c. Displays both client and server sessions.
(1) Listing the remote computers by IP address only.
(2) Attempts to convert the remote computer IP address to a name using the HOSTS file.
d. Utility lists:
(1) Remote computer’s name table
(2) Remote computer’s name table using its IP address
(3) Contents of the NetBIOS name cache, giving the IP address of each name
(4) Local NetBIOS names
(5) Name resolution statistics for Windows networking name resolution
4. Bottlenecks
A. Overview
1. Network activities involve the coordinated actions of several devices.
2. Devices take a certain amount of time to perform transactions.
3. Devices using noticeably more CPU time result in poor performance.
4. Performance monitoring helps identify the problem device and bottleneck.
5. Administrator identifies devices taking too much time to perform tasks.
6. Bottlenecks usually indicate a need to upgrade a portion of the network.
B. Devices that often become bottlenecks:
1. CPUs
2. Memory
3. NICs
4. Disk controllers
5. Network media
C. Reasons a device becomes a bottleneck:
1. Inefficient use
2. Using other resources or CPU time more than it should
3. Too slow
4. Does not have the capacity to handle the load placed on it
5. Documenting Server Performance
A. Overview
1. Affected by an increase in the number of users on the system.
2. Comparing current performance statistics to initial baseline reveals faults.
3. Poor performance clues may come from end users first.
4. End users’ familiarity with system response is a good indicator of server performance.
B. Performance Monitors
1. Track server performance on a network and can monitor several system functions.
2. Observe the performance of a remote system and alert the system administrator to server conditions that need attention.
3. Can transfer data to other performance tools.
C. Indicators that help locate and isolate problems with server performance:
1. Demand for server resources
2. Areas of data congestion
3. Activity of an individual process
6. Total System Management
A. Overview
1. System management software complements other system management utilities found in the NOS.
2. Vendors have developed utilities that do for system management what performance monitors have done for system monitoring.
3. System management applications provide centralized management for distributed systems programs.
4. System management software provides centralized administration of computers in a WAN and includes:
a. Collecting hardware and software inventory information
b. Distributing and installing software
c. Sharing network applications
d. Troubleshooting hardware and software problems
B. Examples using Microsoft’s Systems Management Server (SMS) include:
1. Inventory Management
a. Software collects and maintains an inventory of hardware and software for each computer and stores it in a database.
b. Typical inventory items include the type of CPU, amount of RAM, hard disk size, operating system, and application software for each component installed.
2. Software Distribution
a. A utility that can install and configure new software or upgrade previously installed software directly on a client.
b. Used to run commands, such as virus scan, on clients.
3. Shared Application Management
a. Shared applications that can be distributed to a server for clients to access.
b. Management software builds folders on each client that contain other folders and program icons that represent the shared applications.
c. These applications are actually stored on the server.
4. Remote Control and Network Monitor
a. Help Desk software and diagnostic utilities allow administrators to control and monitor remote clients directly.
b. Diagnostic utilities allow administrators to view a client’s current configuration.
7. Maintaining a Network History
A. Network’s Written Record
1. Indicates significant performance or equipment issues that real-time monitoring might miss.
2. Provides a background to compare against current information.
B. Logbook
1. Important that all information be recorded in only one shared logbook.
2. Invaluable for tracing a performance problem or resolving network issues related to system growth.
3. Network documentation should be easy to read and access.
4. Graphics and hand-drawn sketches can be very helpful.
5. History can be either logged online or in a notebook.
6. Storing on a hard disk can cause difficulties if the computer or disk crashes.
C. Log Records Include:
1. Purchase and installation dates and descriptions
2. Complete information about key individuals, such as contractors responsible for installation
3. Vendor, model, and warranty information, including serial numbers
4. Installation process and its results
5. Initial and subsequent network configurations
6. Network usage policies and procedures
7. Network resources and drive assignments
8. Copies of crucial network configuration files, such as CONFGI.SYS and AUTOEXEC.BAT files
9. Unusual application program configurations
10. Particular computer, board, or peripheral settings
11. Problems and their solutions
12. Hardware or software changes
13. Activities that affect the topology or architecture
Chapter 12, Lesson 2
Upgrading a Network
1. Overview
A. Document the network, record the performance baseline, and identify the need for an upgrade.
B. Determine which network elements can be upgraded and assess the costs and benefits of doing so.
2. Deciding to Upgrade a Network
A. Timing the Upgrade
1. Addition of new programs and devices to a network is usually a slow process.
2. Need to upgrade might not be immediately apparent, but will evolve slowly over time.
3. Documenting network performance and listening to end users will help determine when the time has come to upgrade the network.
4. If the response time of the CPU and network devices is too slow to adequately handle increased user demand and the requirements of new software.
5. Growing demands for resources might necessitate an upgrade.
6. Administrator can refer to the original network plan to review the types of applications the network was initially intended to run.
B. Upgrading Network Architecture and Media
1. When to upgrade from copper-based media to fiber-optic media:
a. If devices have been added that create large amounts of electrical interference.
b. If the size and number of networked buildings are expanding.
c. Fiber-optic media can be used for cable runs between remote buildings.
d. If online conferencing or advanced Web applications at the desktop are introduced.
2. Cost of fiber-optic media
a. Price is dropping, but installation of fiber-optic cable requires a trained technician, which is an added expense.
b. NICs, hubs, and other network hardware will need to be upgraded at the same time.
c. New network maintenance expenses are likely to arise that were not incurred with simple, copper-based media.
3. Other options
a. Microwave send-and-receive station between the two buildings.
b. Use of microwave components in a network requires either line-of-sight between the two stations or access to repeaters.
4. Other considerations
a. Consider the negative aspects of a potential upgrade as well as the benefits.
b. In microwave networking, meteorological conditions merit consideration: fog, rain, and snow can weaken and distort a microwave signal.
C. Upgrading from a Peer-to-Peer to a Server-Based Network
1. The following indicate a need to upgrade to a server-based network:
a. Current peer-to-peer network causes inappropriate access to secure information.
b. Organizational expansion.
c. Users having difficulty administering their own workstations.
d. Need for a dedicated file server.
e. Only one person understands how the network operates.
2. An upgrade to a server-based network will provide these benefits:
a. Network can handle more users.
b. Sensitive data will be secure from unauthorized users.
c. A knowledgeable network administrator can assist users.
d. Data backups will be easier to schedule and perform.
e. Workload of multiple servers can be balanced for better efficiency.
f. Servers can be physically isolated for additional security.
g. Servers that handle complex tasks can be upgraded for top performance.
h. More advanced users can have their network components upgraded for top performance.
3. By compiling supporting documentation that identifies areas in which system performance needs to improve, network administrators can build a case for appropriate change.
3. Server-Based Networks
A. Overview
1. Can be costly and difficult, although the advantages will frequently outweigh the disadvantages.
2. A new server can be a good information-technology investment.
3. Benefits include faster processing of requests and the ability to handle more users and run more sophisticated software applications.
4. Can consist of a single device or several servers that have been interconnected for increased processing power.
B. Deciding to Upgrade a Server
1. Initial Considerations
a. Symptoms point to the need for a server upgrade.
b. Compare initial baseline values with the current values.
c. Start with the component of the server that is taking more time to complete the task than it should.
d. Consult the server’s manufacturer for information about the latest products and choices for the network.
2. CPU and Memory
a. If the server’s CPU requires extra time to exchange data between memory and the disks, there might not be enough memory available for the CPU to function efficiently.