Chapter Overview

1
Chapter Overview

• Documentation and Resources
• Logs and Indicators
• Network Testing and Monitoring Tools

2
Product Documentation

• Hardware and software products usually include
  documentation in some form.
• You should always keep all product documentation.
  
• Although you may be familiar with the devices or
  software products you use, you might still need
  the documentation later when you need to
  reinstall, upgrade, or troubleshoot the network.

3
CD-ROM Documentation Formats

• Text files. Many manufacturers use plain ASCII
  text files to provide late-breaking information
  about product problems, revisions, and
  compatibility issues.
• Hypertext Markup Language Files. Some
  manufacturers create documentation in Hypertext
  Markup Language (HTML) format and include it with
  the product on a CD-ROM.
• Adobe Acrobat Portable Document Format files.
  Acrobat creates and displays documents in a
  proprietary format called the Portable Document
  Format (PDF).
• PDF files preserve all the original design
  elements, layout, and formatting characteristics
  of the original documents.
• The .pdf format has become a de facto publishing
  standard in the computing industry.

4
An Example of an Adobe Acrobat PDF File
5
Telephone Support

• Free telephone support is a thing of the past.
• Some products include free technical support for
  a limited time or a limited number of incidents
  before the manufacturer begins charging a fee.
• Because of the expense, determining when to call
  for help is more difficult than it used to be.
• People are more likely to find other sources of
  support before paying for help.
• Sometimes calling for technical support is
  necessary.
• Look for help on the Web and Usenet first, and
  call technical support as a last resort.

6
Online Resources

• Marketing collateral. Includes datasheets,
  features and benefits lists, product comparisons,
  product reviews, and other sales literature
• Product manuals. Can be more valuable if the site
  has a search engine
• Technical documents. Frequently more concerned
  with the theoretical aspects of the product than
  with day-to-day operations
• Frequently asked questions (FAQs). Address common
  problems can be an excellent product evaluation
  resource
• Technical support databases. Let you search for
  keywords or error messages, and provide
  information on solutions and links to software
  patches

7
Online Resources (Cont.)

• File downloads. Let you see how many patches have
  been issued for a product, which is a good way of
  evaluating the product before buying it
• Online messaging. The Web equivalent of the old
  bulletin board systems, where you leave a text
  message and receive a reply from a technical
  support representative
• Live support. Usually a chat application that
  provides a live text-messaging link between users
  and company representatives
• Manufacturers contact information. E-mail
  addresses and telephone numbers for technical
  support, and other contact information

8
Usenet

• Usenet is a worldwide, text-based Internet
  bulletin board system that consists of newsgroups
  devoted to many topics.
• Usenet is not as user-friendly as the Web, but it
  provides an enormous amount of valuable technical
  information.
• To access Usenet newsgroups, you must have a
  newsreader client program and access to a news
  server.
• The clients and servers communicate with each
  other by using a specialized TCP/IP protocol
  called the Network News Transfer Protocol (NNTP).
  
• Most Internet service providers (ISPs) include
  access to a news server as part of a standard
  Internet access subscription, but the quality of
  the service varies.

9
The Usenet Newsgroup List
10
Usenet Message Headers
11
A Usenet Newsgroup Message
12
The Microsoft TechNet Interface
13
Books and Periodicals

• Networking and computer books are an excellent
  resource for background information and
  networking theory.
• Many books include a searchable electronic
  version on a CD-ROM.
• Magazines and trade newspapers are good places to
  look for current technical information and
  industry news.
• Keep in mind that information in a typical
  monthly magazine is written at least three to
  four months before you see the issue.
• Weeklies usually provide more timely information.
  
• Many weekly trade newspapers are now available
  online.

14
Link Pulse Lights

• Most Ethernet network interface adapters that use
  unshielded twisted-pair (UTP) cable have a
  light-emitting diode (LED) that is lit when the
  adapter is connected to a functioning hub.
• The hub usually has an additional LED for each
  port that indicates from either end of the patch
  cable whether the devices are connected.
• Link pulse lights can tell you whether a computer
  is wired to the hub properly.
• When an Ethernet adapter and a hub are properly
  connected, they exchange signals to test the
  connection.

15
The Link Pulse LED on a Network Interface Adapter
16
The Link Pulse LED on a Hub
17
Normal Link Pulse (NLP) Signals

• On 10Base-T and 10Base-FL equipment, the signal
  exchanged by network interface adapters and hubs
  is called a normal link pulse (NLP).
• The NLP signals
• Last for 2 milliseconds
• Repeat at intervals of 16.8 milliseconds
• Occur only when the network is not busy
  transmitting data, so they do not interfere with
  normal operations
• When the LEDs at both ends of the connection are
  lit, the NLP signals generated by each device are
  reaching the other device.

18
Fast Link Pulse Signals

• Fast Ethernet and Gigabit Ethernet equipment that
  supports multiple speeds uses fast link pulse
  (FLP) signals.
• FLP signals differ from NLP signals in that they
  include a 16-bit data packet that the devices use
  to autonegotiate their connection speed.
• The data packet contains a link code word that
  consists of a selector field and a technology
  ability field.
• The devices use these fields to advertise their
  capabilities, including the speeds they can run
  at and whether they support full-duplex
  communications.
• By examining the link code word supplied by the
  other device, the network interface adapter and
  the hub both configure themselves to use the best
  transmission mode that they have in common.
• FLP signals are fully compatible with the NLP
  signals that are used by devices that cannot
  operate at multiple speeds.

19
Error Displays

• The most obvious indication of a computer problem
  is an error message.
• Error messages are generated primarily by
  applications and operating systems.
• In most cases, error messages cannot give you
  specific information about a problem with the
  network itself.
• There is usually no way for the computer to test
  or communicate with network components except for
  other computers.
• An error message generated by an operating system
  might tell you that the computer could not
  communicate with another computer on the network,
  but it usually cannot tell you why unless the
  problem is with the computer generating the
  message.
• If you do not understand an error message, record
  the exact message, including all number and
  letter codes, memory addresses, and other types
  of information.

20
Event Logs

• An event log is a running record of processes
  that documents an operational history of the
  product involved.
• Many applications, operating systems, and
  networking components maintain logs of their
  activities.
• You should check the logs on a regular basis.
• Some applications let you specify whether you
  want them to log their activities and how much
  detail you want in the logs.
• You should consider the amount of detail you want
  in the logs.
• Selecting the most detailed option might not
  always be best.

21
The General Properties Tab in the IIS Extended
Logging Properties Dialog Box
22
The Extended Properties Tab in the IIS Extended
Logging Properties Dialog Box
23
The Windows 2000 Event Viewer
24
Event Viewer

• Some logs are maintained and displayed by a
  separate application, such as the Event Viewer
  included in Microsoft Windows 2000 and Microsoft
  Windows NT.
• To launch Event Viewer in Windows 2000, select
  Event Viewer on the Start menus
  Programs/Administrative Tools group.
• By default, the application displays the logs for
  the current system.
• You can also view the logs of another computer
  running Windows 2000.

25
Event Viewer (Cont.)

• Event Viewer maintains lists of messages
  generated by various elements of the operating
  system.
• Each log entry is listed as a separate item with
  the date and time that it was generated, the
  process that generated it, the event ID, and
  other important information.
• By default, Microsoft Windows 2000 Professional
  contains three different logsan Application Log,
  a Security Log, and a System Logall of which are
  maintained independently.
• The Microsoft Windows 2000 Server products
  include these three logs, plus others, depending
  on the services installed.
• Each event in each log is classified as
  Information, Warning, or Error.  

26
The Event Properties Dialog Box
27
Network Management Products

• Error messages generated by network components,
  such as routers or computers at remote locations,
  can be difficult to monitor.
• A stand-alone router does not have a screen to
  display error messages, but many networking
  devices can supply information about their
  status.
• Network management products provide a
  comprehensive view of network systems and
  processes.
• These products use a distributed architecture
  based on a specialized management protocol, such
  as the Simple Network Management Protocol (SNMP)
  or the Remote Monitoring (RMON) protocol.
• Network management products often include other
  functions, such as software distribution and
  metering, network diagnostics, network traffic
  monitoring, and report generation.
• Deploying a network management system is a
  complex undertaking.

28
SNMP

• SNMP is a Transmission Control Protocol/Internet
  Protocol (TCP/IP) application layer protocol and
  query language that specially equipped networking
  devices use to communicate with a central
  console.
• Many networking hardware and software products
  use SNMP agents to
• Gather information about the product and deliver
  it to a computer designated as the network
  management console
• Gather specific information about the network
  devices and store it as managed objects in a
  management information base (MIB)
• SNMP agents transmit MIBs to the console using
  SNMP messages, which are carried inside User
  Datagram Protocol (UDP) datagrams.
• The console collates the information received
  from the agents and provides a composite picture
  of the network and its processes.
• An agent can generate a special message called a
  trap, which causes the console to alert of a
  potentially dangerous condition.

29
Windows 2000 System Monitor
30
The Add Counters Dialog Box in System Monitor
31
The Performance Console in System Monitor
32
The Performance Logs and Alerts Feature in the
Performance Console
33
The Novell Netware MONITOR.NLM Application
34
Protocol Analyzers

• A protocol analyzer captures a sample of network
  traffic, decodes the packets into the language of
  the individual protocols that they contain, and
  lets you examine them in detail.
• Capturing and displaying network traffic is
  relatively easy, but interpreting and using the
  information for troubleshooting requires a
  detailed understanding of networking protocols.
• Protocol analyzers are useful tools, but they can
  also be used for malicious purposes.
• A protocol analyzer can be either
• A device with a proprietary interface that you
  connect to a network to capture traffic, or
• A software program that runs on a computer that
  is already connected to the network
• Protocol analyzers typically work by switching
  their network interface adapter into promiscuous
  mode.

35
The Network Monitor Capture Summary Window
36
The Network Monitor Detailed Information Display
37
An Expanded TCP Header
38
The Network Monitor Raw Data Display
39
Crossover Cables

• A crossover cable is a good tool to use for
  eliminating the hub and the cables as possible
  sources of a network communications problem.
• If two computers seem to be properly connected
  with a hub and prefabricated cables (or an
  internal cable run and patch cables), and they
  are not communicating, try connecting the
  computers with a crossover cable that you know
  works properly.
• If the computers can communicate with the
  crossover cable, the problem is in either the hub
  or the cables connecting the computer to the hub.
  
• If the computers fail to communicate with the
  crossover cable, the problem is in one or both of
  the computers or network interface adapters.

40
Hardware Loopback Connectors

• A loopback connector is an inexpensive device
  that you plug into a jack.
• The loopback connector redirects the outgoing
  signals from the device right back into it.
• Many adapters have a diagnostic utility built
  into their configuration programs.
• After plugging the loopback connector into the
  adapter port, you run the diagnostic program, and
  the loopback connector transmits a series of
  signals out through the adapter.
• If the adapter receives the signals back in
  exactly the same format as they were sent, the
  adapter passes the test.

41
A Typical Tone Generator and Locator
42
Tone Generators and Locators

• A basic way to identify and test a cable
  connection is to use a tone generator and
  locator, also known as a "fox and hound" cable
  tester.
• You connect a tone generator to a cable at one
  end, and it transmits a signal over the cable.
• The tone locator is a separate device that can
  detect the generator's signal, either by touching
  it to the conductor in the cable or by touching
  it to the cable insulation.
• When the locator detects the generator's signal,
  it emits an audible tone.
• You can use a tone generator and locator to test
  an entire cable or to test the individual wire
  connections inside a UTP cable.
• Tone generators and locators are most commonly
  used to identify the cable that belongs to a
  particular connection.
• The tone generator and locator is the simplest
  and most inexpensive type of cable tester.

43
Wire Map Testers

• A wire map tester is similar in principle to the
  tone generator and locator, except that it tests
  all the wire connections in a UTP cable at once.
• A wire map tester consists of two parts that you
  connect to the opposite ends of a cable.
• The unit at one end transmits signals over all
  the wires, which are detected by the unit at the
  other end.
• A wire map tester can detect transposed wires,
  open circuits, and shorts, just as a tone
  generator and locator can.
• However, it does all the tests simultaneously and
  provides you with a simple readout telling you
  what is wrong.
• The one common cable fault that a typical
  stand-alone wire map tester cannot detect is a
  split pair.
• Wire map testers are relatively inexpensive
  stand-alone devices and are good investments for
  small- to medium-sized internal cable
  installations.

44
A Typical Multifunction Cable Tester
45
Multifunction Cable Testers

• Handheld devices that test cable connections and
  compare the results to standard values that have
  been programmed into the unit
• Display a list of pass or fail ratings for the
  individual tests
• Can perform basic wire mapping tests in addition
  to testing length, attenuation, near end
  crosstalk (NEXT), power sum NEXT (PSNEXT), equal
  level far end crosstalk (ELFEXT), power sum
  ELFEXT (PSELFEXT), propagation delay, delay skew,
  and return loss 

46
Multifunction Cable Testers (Cont.) 

• Multifunction cable testers can be dangerous
  because of the very strengths they advertise.
• Some marketing materials imply that you can rely
  on the device to tell you if the cables are
  installed correctly, without knowing what the
  measurements mean.
• This is true, if the tester is calibrated to the
  proper standards.
• If you do not know what each test represents, you
  are relying on the manufacturer of the device to
  set it to the proper standards.
• In some cases, official standards for certain
  cable types have not yet been ratified.

47
Chapter Summary

• Documentation and resources
• Product documentation can be a valuable network
  troubleshooting tool.
• You should always keep all the documentation that
  comes with your hardware and software.
• Web sites for many hardware and software
  manufacturers offer a variety of resources for
  the network administrator, including technical
  documents, FAQs, online messaging, and technical
  support databases.

48
Chapter Summary (Cont.)

• Logs and indicators
• LEDs and other lights are frequently useful
  indicators of a piece of a hardware components
  current status.
• The link pulse LEDs on Ethernet hubs and network
  interface adapters indicate when these devices
  are connected properly.
• Tools like the Windows 2000 Performance console
  enable you to monitor ongoing computer and
  network operations in real time.

49
Chapter Summary (Cont.)

• Network testing and monitoring tools
• A tone generator and locator is a simple
  cable-testing device that determines whether a
  cable is carrying a signal.
• Wire map testers test all four of the wire pairs
  in a UTP cable at the same time.
• Multifunction cable testers perform a
  comprehensive battery of tests on a cable
  connection and compare the results to established
  standards.