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We conclude our review of the Networking Essentials
examination with an equally comprehensive examination of sections three and four –
Implementation and Troubleshooting. As always, we will start by listing the subjects
covered in each section, then spend some time examining some of the specific questions
that tend to crop up regularly and give tips on how to answer them.
The Implementation Section
What to Revise
Using Encryption to Protect Data, WAN Link selection, Audit Policies, Restricting
Administrative rights, 10BaseFL, CSNW and GSNW, Preventing Data Loss, NetBIOS Names and
Host Names, Selecting a Connectivity Device, Cable Characteristics, Sector Sparing, Access
Methods, Centralised versus Departmental Servers.
Watch For:
1. WAN Link Selection.
Only digital lines can transmit voice and data simultaneously.
2. Audit Policies
In Windows NT, you can track successes and failures of user actions (such as logging on or
using an application) by implementing an Audit Policy. The events that you choose to audit
are logged and can be viewed in the Event Viewer utility.
3. Restricting Administrative rights
You may be asked how to restrict administrative rights to just a small subset of your
entire number of users. To do this, add the users that you wish to remain as
administrators (for example yourself and two of your colleagues) into the Administrators
group and remove all others from that group.
4. CSNW and GSNW
CSNW stands for Client Services for NetWare and is supplied with Windows NT Workstation.
Install it onto each NT Workstation that you wish to have its own redirector for NetWare
so that each server can access resources on NetWare servers.
GSNW stands for Gateway Services for NetWare and is supplied with Windows NT Server.
Install it just the once onto an NT Server so that the NT Server can act as a gateway
(translator) for all Microsoft clients that do not have their own NetWare redirector
installed, but who need to access resources on NetWare servers.
5. Preventing Data Loss
A small point, but worth getting right in the examination. Your first line of defence
against unexpected data loss is a daily backup to tape.
6. Selecting a Connectivity Device
Connectivity devices (repeaters, bridges, routers, brouters and gateways) come up in all
sections of the exam. In this section, you may get a scenario question where you need to
choose the appropriate connectivity device to suit the scenario. Make sure you know which
device to use in which circumstances.
7. Cable Characteristics
Familiarise yourself with the different types of cable and their main characteristics. You
are often given a scenario question where you have to pick the right cable to use given
certain distances from a wiring closet that the cable will have to reach, so revise your
maximum cable lengths.
UTP = 100m or 328ft
Thinnet = 185m or 607ft
Thicknet = 500m or 1640ft
8. Sector Sparing
Sector Sparing is the ability for a hard disk to detect bad sectors when saving files,
resave the file elsewhere and map the bad sectors out. Only SCSI hard disks can have this
facility.
9. Access Methods
Make sure you have definitions for each access method.
CSMA/CD = computer checks the cable for traffic before sending message
CSMA/CA = computer signals its intent to transmit before doing so
Token Passing = only the computer holding the token may transmit
Demand Priority = transmissions are controlled centrally by the hub
10. Centralised versus Departmental Servers
With centralised servers, all servers are reachable by all departments, but all servers
are one hop away (i.e. one router must be crossed to access them). With departmental
servers, each department keeps its own server/s on its own local subnet (i.e. no routers
to cross), but needs to cross at least two hops (i.e. two routers) to get hold of data
stored on servers belonging to other departments. The model you choose will usually be
based on whether users from only one department or users from multiple departments need to
access data on your servers. Most companies end up with a mixture of both centralised and
departmental servers to best suit their needs.
The Troubleshooting Section
What to Revise:
Port Configuration
Hardware Configuration
Broadcast Storms
Tools for Gathering Performance Data
Problem Solving Failed Networks
Optimising Network Performance
Tools for Network Management
Creating and Editing User Accounts
Optimising TCP/IP
Beaconing
Backup Types
IPX/SPX Frame Types
NFS
Name Resolution Methods
Watch For:
1. Port Configuration
You may be asked a question where you need to know which IRQs are used by LPT and COM
ports.
| Port |
Default IRQ setting |
| COM1 & COM3 |
4 |
| COM2 & COM4 |
3 |
| LPT1 |
7 |
| LPT2 |
5 |
2. Hardware Configuration
The most likely layer to cause network problems is the physical layer. The most likely
hardware-related problem is incorrect configuration of resources – IRQ, I/O, Base
Memory and DMA.
3. Broadcast Storms
Broadcast storms occur when the number of broadcasts exceeds the bandwidth capacity of the
network. To prevent broadcast storms, divide your network into multiple segments using
routers (which do not propagate broadcasts).
4. Tools for Gathering Performance Data
Be familiar with what each tool is used for and when and how it is used.
| Name
of Tool |
Description |
| Protocol Analyser |
Analyses network
activity in order to optimise performance or troubleshoot problems by capturing and
analysing the contents of packets |
| Network Analyser |
Another name for the
above |
| Network Monitor |
The name for the
protocol analyser that comes with Windows NT and SMS (Systems Management Server). The
full, SMS version allows you to capture all packets on the local subnet by putting the
network interface card into promiscuous mode. The cut-down, NT version can only capture
packets sent to or from that computer, plus broadcasts. |
| Performance Monitor |
A utility that comes
with Windows NT that allows you to view, in real time or from saved files, the performance
of objects such as processor, memory, disk and network. Used primarily for performance
optimisation but useful also for troubleshooting. |
| Volt-Ohm Meter |
Resistance in ohms is
used to check for shorts (should measure 0) or opens (should measure high). Power in volts
is used to check for opens. |
| Oscilloscopes |
Can be used (in
conjunction with a Time-Domain Reflectometer) to monitor the status of your cable plant |
| Time-Domain
Reflectometers |
Provides information
on the current status of your cable plant and can detect the location of opens or shorts. |
| Advanced Cable Testers |
Display information
about the condition of the physical cable as well as the protocols running over the
network |
5. Problem Solving Failed Networks
Bus Networks
You may get a scenario question about troubleshooting a bus network. If the only computer
that cannot access the server is a single client then the problem lies with the client. If
no clients can access the server then the problem is either the server, a cable break or
faulty termination.
Star Networks
You may get a scenario question about troubleshooting a star network. A faulty cable on a
star network will only affect the client connected via that cable to the hub, all other
computers will continue to be able to access the network. Because of this, a star network
is easier to troubleshoot cabling problems on than a bus network.
6. Optimising Network Performance
To optimise network performance, disable any networking components (adapters, protocols
and/or services) that you do not need.
7. Tools for Network Management
The two tools for network management that crop up in the exam are SMS (Microsoft Systems
Management Server) and SNMP (Simple Network Management Protocol).
SMS is Microsoft’s own utility, which can be bought either separately or as part of
the BackOffice suite. SMS allows you to view configuration and usage information for your
clients and remotely install applications. It also comes with the full version of Network
Monitor.
SNMP is an open standard that runs over a TCP/IP network and is used to send management
information between SNMP clients and SNMP management utilities. Microsoft does not make an
SNMP management utility, although Windows NT can be an SNMP client. SNMP is mostly used
for gathering statistics, although it can be used, to a limited extent, to configure
clients remotely.
8. Creating and Editing User Accounts
The Windows NT utility used to create, edit and delete user and group accounts is called
user Manager for Domains.
9. Optimising TCP/IP
To optimise network traffic when running TCP/IP over a reliable network, increase the size
of the Receive Window. This will allow more data to be sent before an acknowledgement is
required, thus speeding up the overall process of transmitting data over the network. For
an unreliable network, you could reduce the Receive Window size to prevent large
re-transmissions being required when a data transmission fails.
10. Beaconing
Beaconing is the process used in a token passing network to detect the location of a fault
on the ring. When a computer detects a fault, it transmits a broadcast which is sent back
down the ring. The broadcast packet includes the address of the upstream computer that has
the fault. In this way, faults can be easily located on a token ring network.
11. Backup Types
Be familiar with definitions of each of the different types of backup that can be
performed.
| Backup Type |
Description |
| Full (or Normal) |
Backs up all files selected for backup,
regardless of how the archive attribute is set. Sets the attribute bit to show that the
files have been backed up. |
| Copy |
Backs up all files selected for backup,
regardless of how the archive attribute is set. Does not set the attribute bit to show
that the files have been backed up. |
| Daily |
Backs up all files selected for backup which
have been created or edited on that day, regardless of how the archive attribute is set.
Does not set the attribute bit to show that the files have been backed up. |
| Incremental |
Backs up only those files selected for backup
whose attribute shows that they have been changed since the last backup. Sets the
attribute bit to show that the files have been backed up. |
| Differential |
Backs up only those files selected for backup
whose attribute shows that they have been changed since the last backup. Does not set the
attribute bit to show that the files have been backed up. |
12. NFS
NFS is a Unix file system that you can purchase and install as an add-on service to an NT
Server. NFS will allow an NT Server to share resources for access by Unix workstations.
13. You need to understand the differences between the different
methods of resolving names into IP addresses on an NT-based TCP/IP network.
| Resolution
Method |
Description |
| WINS |
Server-based dynamic database used for NetBIOS
to IP address resolution |
| LMHOSTS |
Locally stored text file used for NetBIOS to IP
address resolution |
| DNS |
Server based static database used for Host name
to IP address resolution |
| HOSTS |
Locally stored text file used for Host name to
IP address resolution |
Now that we have fully covered the four
sections in the Networking Essentials examination, you should be in a position to start
your preparation for the exam. Concentrate on one section at a time, and first of all make
sure that you understand all of the concepts. I suggest that you go out and invest in one
of the many Networking Essentials study guides that are available from Microsoft Press,
QUE and other publishers. Once you are happy with your understanding of the first section,
move on to the next. Try to get hold of preparation test software such as the excellent
Transcender tests so that you can test to see how much knowledge you have retained.
Concentrate your revision on remembering the facts and figures presented in this article
as there are a lot of questions about definitions and specifications for things like hubs
and cables etc. Remember that the Networking Essentials examination is now adaptive so
expect a short exam with around 25 questions. So far, all the students that I have taught
that have taken the adaptive examination have passed and said that it wasn’t too
difficult. Good luck!.
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