Title: Networking
1Networking
2Overview
- In this chapter, you will learn to
- Explain network technologies
- Explain network operating systems
- Install and configure wired networks
- Install and configure wireless networks
- Troubleshoot networks
3The Big Questions
- How will each computer be identified?
- If two or more computers want to talk at the same
time, how do you ensure all conversations are
understood? - What kind of wire should be used to connect the
computers together? - How many wires in the cable? How thick? How long?
What type of connectors? - How can access to data and peripherals be
controlled? - And the list goes on and on
4A Few Basics
- A client machine requests information or
services - Uses a network interface card (NIC) to define the
client on the network and to physically make a
connection - A medium to connect the devices is needed
- Cable or wireless
- The operating system needs to understand how to
network - A server provides information or services to the
client
5Packets, Frames, and NICs
- Data is broken up into small pieces and moved
about the network in chunks called packets or
frames - Every network interface card (NIC) has a built-in
identifier called a Media Access Control (MAC)
address - No two NICs have the same MAC address anywhere in
the world - Burned into a chip on the card
6MAC Address
- Start ? Programs ? Accesories ? System Tools ?
System Information
7Packet Fields
- Packets contain the following fields
- MAC address of the network card that it is being
sent to - MAC address of the network card that sent the
packet - Data
- Data check or cyclic redundancy check
(CRC) used to verify the datas
integrity
8Protocols
- Protocols are sets of rules
- May be used to define packet types, cabling and
connectors, addresses, and much more - A hardware protocol defines how to get data from
one computer to another - Ethernet is the dominant standard for todays
networks - Coaxial
- Unshielded twisted pair
- Fiber optic
- Token Ring was developed by IBM but is losing
popularity
9Coaxial Ethernet
- Early Ethernet networks used coaxial cable (or
just coax) - Composed of a center cable surrounded by
insulation, a shield of braided cable, and an
outside protective cover - A different type of coaxial cable is used by your
VCR and TV
10Thick Ethernet 10Base5
- Thick Ethernet cable (Thicknet) is used in
the 10Base5
Ethernet specification - Called RG-8 (Radio Grade) cable
- 10Base5
- 10 means that data is transferred at 10 Mbps
- Base refers to baseband signaling
- 5 means the maximum length of the cable is 500
meters - Uses a bus topology where all devices attach to a
single cable - Computers are connected one to another
- Every computer receives every packet of
information
11CSMA/CD
- Carrier Sense Multiple Access/Collision Detection
(CSMA/CD) is a method used by computers to share
the same cable - If two computers talk (try to send data) at the
same time, a collision results that corrupts the
data
12CSMA/CD
- To prevent collisions when there is multiple
access to a cable, computers first do a carrier
sense (listen to the cable for traffic) before
trying to send data
13CSMA/CD
- Even though the computers listen before sending
data, it is possible that two computers listened
at about the same time, heard nothing, and then
sent data resulting in a collision - Computer NICs have collision detection circuitry
that alerts them to a collision
14Reflection and Termination
- Signals traveling along a wire will bounce back
when they get to the end called reflection - As a result a terminator is installed on the ends
of the cable to absorb the signal to prevent it
from reflecting back which would corrupt the
signal
15Thicknet Connections
16Connections
- Thicknet cable is marked every 2.5 meters
- Devices are connected only at these marks by
using a vampire connector that pierces the cable
to make a connection - It is also a transceiver that transmits and
receives data, sometimes called an access unit
interface (AUI) that connects to a Digital,
Intel, Xerox (DIX) connector - Thicknet uses a bus topology
- If theres a break in the cable, the whole
network goes down
17Thin Ethernet 10Base2
- Thin Ethernet is also known as
Thinnet - Uses RG-58 coax cable
- Limited to 30 devices per
segment - Cable length limited to 185 meters
- Thinner and cheaper than Thicknet
- Transceiver is built into the network card
- Uses twist-on BNC connectors
- Uses terminators
18UTP Ethernet 10BaseT
- Modern networks use UTP Ethernet
- Modern networks do not use Thicknet or Thinnet
- 10BaseT runs at 10 Mbps
- 100BaseT runs at 100 Mbps
- 1000BaseT (Gigabit) runs at 1000 Mbps
- Use a star bus topology
- Uses unshielded twisted pair (UTP) cabling
19Plenum vs. PVC
- Most workplace installations of network cable go
up above the ceiling and then drop down through
the walls to present a nice port in the wall. The
only potential problem with this cabling running
through the walls and ceiling is that the
protective sheathing for networking cables is
made from plastic, and if you get any plastic hot
enough, it will create smoke and noxious fumes.
To reduce the risk caused by burning buildings,
all cables have fire ratings. The two most common
fire ratings are PVC and Plenum. PVC (Poly-Vinyl
Chloride) has no significant fire protection. If
you burn a PVC cable, it creates lots of smoke
and noxious fumes. Burning Plenum cable creates
much less smoke and fumes, but Plenum costs about
three to five times as much as PVC. Most city
ordinances require the use of Plenum-rated cable
for network installations
20Star Bus Topology
- Most common topology used is a star bus
- In a star topology all devices are connected to a
central device called a hub - Multiple hubs are connected together in a bus
topology - Together they form a star bus topology
- Hubs have been replaced by switches that conserve
bandwidth
21Why is a switch better than a hub?
- If you put 32 computers on a 32-port 100BaseT
hub, for example, they are sharing the 100Mbps
bandwidth ? not getting 100Mbps each. - A switch makes each port a separate Ethernet
network ? each computer gets the full bandwidth
available, and avoid collisions.
22Unshielded Twisted Pair
- UTP is the predominant type of cabling used today
- Pairs of wires are twisted together in an
unshielded cable - UTP cables come in categories (CATs) that define
the maximum speed at which data can be
transferred (called bandwidth) - CAT5, CAT5e, and CAT6 are most common today
23Implementing 10BaseT
- Requires at least two pairs of wires one for
receiving and one for sending - Cables use special RJ-45 connectors
- The Telecommunications Industry Association/
Electronics Industries Alliance (TIA/EIA) has two
standards for connecting the RJ-45 connectors - TIA/EIA 568A and TIA/EIA 568B
- Use either. Just be consistent
- Wires are color-coded
24Combo Cards
- All Ethernet networks share the same language
- Many NICs will run at either 10 or 100 Mbps
- Some NICs have both BNC and RJ-45 ports
25Hubs and Switches
- Each PC is connected to a hub or switch in a
10BaseT network - To add a device, just run another cable to the
hub or switch from the device - The maximum separation between the device and the
hub or switch is 100 meters - Hubs act as a repeater that regenerates the
signal before it sends it back out other ports - Hubs come in 4, 8, 16, or 24 ports
26Duplex and Half-Duplex
- Modern NICs can both send and receive data at the
same time called full duplex - Older NICs could send and receive data but not at
the same time called half duplex - NICs and switches use autosensing to decide how
to operate
27Fiber Optic Ethernet
- Fiber optic cable uses light instead of
electricity - Immune to electrical interference
- Signals can travel up to 2,000 meters
- Most Ethernet uses 62.5/125 multimode cable
- Uses two cables
- Uses SC (square-shaped) or ST (round) connectors
- Common standards are 10BaseFL and
100BaseFX - Usually reserved for the backbone due to
its expense
28Token Ring
- Developed by IBM
- Uses a star ring topology
- Incompatible with Ethernet
- Data travels in a ring
- Uses token passing
- A free token circulates the ring
- A device may send data only when it
has the token
29Implementing Token Ring
- Legacy Token Ring ran at 4 Mbps or 16 Mbps
using IBM Type 1 cable - Two-pair, shielded twisted pair (STP) cable
- Todays Token Ring networks may use UTP or
STP - STP comes in various types
- Token Ring cables use an IBM-type Data Connector
(IDC) or Universal Data Connector (UDC) designed
to plug into each other - Uses a special hub called a multi-station access
unit (MSAU or MAU)
30Parallel/Serial Connections
- All versions of Windows have software that allows
two (and only two) PCs to connect together via
their parallel or serial ports - Use a crossover IEEE 1284 cable for parallel
ports - Use an RS-232 cable for serial ports
31Network Operating System
32Client/Server
- In a client/server environment one machine is
dedicated as a resource to be shared over the
network - Uses a special Network Operating System (NOS)
- Optimized for sharing files and printers or other
resources - Protects access to the data or resources using
security features - Called the server
- All other machines are clients or workstations
- Novell NetWare is an enterprise level NOS
- A NetWare server is NOT used directly by any one
? the server doesnt provide a user environment
for running any applications except for tools and
utilities
33Peer-to-Peer
- In a peer-to-peer network all machines on the
network may act as a client or server - Peer-to-peer network operating systems include
- Windows 98/Me
- Windows 2000/XP
- Limited to 10 users accessing a file at one time
- Useful for small networks only
- Lacks security
- Users are part of workgroups
34Peer-to-Peer
35Domain-Based
- In a peer-to-peer network you must log in to each
server you wish to access ? If the network
contains multiple servers, youd have to log-on
and off each time when you want to switch to a
different server - In a domain-based network you log into the
network just once to access resources throughout
the network - Servers on the network may play one or several
roles - Domain Controller (holds the security database)
- File server
- Print server
- Fax server
- Remote Access Services (RAS) server
- Application server
- Web server
36Domain Controllers
- Domain Controllers keep the security database of
users and passwords - Directory services are used to store user names
and passwords - In Windows 2000 and 2003 server, it is called
Active Directory - In Novell NetWare it is called NetWare Directory
Services (NDS)
37Administrative Tools
Administrative Tools in Windows XP Professional
Administrative Tools in Windows 2000 Server
38Administrator Account
- The administrator account is a special user
account that has complete and absolute power over
the entire system - Joining a workgroup or becoming part of a domain
is relatively easy in any version of Windows
39Joining a Workgroup or Domain in Windows 98
40Protocols
- Network protocol software
- Takes the incoming data received by the network
card - Keeps it organized
- Sends it to the application that needs it
- Takes outgoing data from the application and
hands it over to the NIC to be sent out over the
network - The most common protocols used are
- NetBEUI
- IPX/SPX
- TCP/IP
- AppleTalk
41NetBEUI
- NetBIOS Extended User Interface (NetBEUI) ?
developed by IBM in 1980s - Small size
- High speed
- Not routable
- Limited to small networks
- Default protocol for Windows for Workgroups,
LANtastic, and Windows 95
42IPX/SPX
- Internetwork Packet Exchange/ Sequenced Packet
Exchange (IPX/SPX) - Developed by Novell for their NetWare products
- Routable
- NWLink is Microsofts version
43TCP/IP
- Transmission Control Protocol/Internet Protocol
(TCP/IP) - Developed by the U.S. Department of Defense as
ARPANET - Build-in protocol for BSD UNIX and other UNIX
- Used in networks of all sizes
- Used on the Internet
44AppleTalk
- AppleTalk is a proprietary protocol developed by
Apple - Used to communicate with older Apple Computers
- Apples Macintosh OS X supports TCP/IP
45Client and Server Software
- Client software
- Needed to access data and resources on a network
- Windows installs Client for Microsoft Networks
- Server software
- Any Windows PC may be turned into a server by
enabling sharing of files, folders, and printers
46Installing and Configuring a Wired Network
47Network Connectivity
- To connect to a network you need
- Network Interface Card
- Physical hardware that connects the PC to the
network wire - Protocol
- The language the devices will use to communicate
- Network Client
- Allows the computer system to speak to the
protocol - In addition, if you would like share your files
or printer, you need to enable Microsofts File
and Print Sharing
48Installing a NIC
- When choosing a NIC there are three requirements
- Must run at the proper speed (many NICs run at
more than one speed) - Must be for the proper technology
- Ethernet, Token Ring, Fiber optic (FDDI)
- Must fit into your expansion slot
- ISA, PCI
- If your NIC does not autoinstall, then use the
Add Hardware wizard in Control Panel
49Configuring a Network Client
- You need a network client for each type of server
NOS - Client for Microsoft Networks
- Alt-click My Network Places (or Network
Neighborhood) and choose Properties - Double-click the Local Area Connection icon (or
choose to Create a New Network Connection) and
choose Properties - Client for Microsoft Networks is automatically
installed when you install a NIC in Windows - Client Service for NetWare
- Provides access to file and print services on
NetWare servers
50Client for Microsoft Networks
51NetBEUI
- NetBEUI
- Windows 2000 Start ?Settings ?Network and Dialup
Connections ?Double-click the Local Area
Connection icon - Windows 9x/Me Start ?Settings ?Control Panel
?double-click the Network applet - Click the Properties button
- Install button ?highlight Protocols and click Add
?NetBEUI - Windows XP has dropped support for NetBEUI
52NetBEUI
53NWLink
- Microsofts implementation of IPX/SPX
- Youll also need to install Client Services for
NetWare - Install the same way you install NetBEUI but
choose NWLink instead
54Configuring TCP/IP
- TCP/IP is the most widely used protocol stack in
networks today - It is the protocol of choice for the Internet but
may also be used on small private networks - TCP/IP is installed just like NetBEUI and NWLink
just choose Internet Protocol (TCP/IP) - Youll need to configure and IP address and a
Subnet Mask at the very least
55IP Addresses
- Part of an IP address represents the network or
subnet (network ID), while the other part
represents the individual device (host ID) on
that given network or subnet - Consists of four sets of 8 binary numbers
(octets) separated by a period - Called dotted-decimal notation
- Examples are 10.1.209.5, 202.34.16.11
- In binary the second example is
- 11001010.00100010.00010000.00001011
56Classes of Addresses
- IP addresses are broken into classes based on the
size of the network - Class A IP addresses are for large companies
- The first 8 bits or octet is used to define the
network - The other 3 octets are used to define the hosts
- The first octet begins with 0
- Class B IP addresses are for medium size
companies - The first two octets define the network
- The last two octets define the hosts on each
network - The first octet begins with 10
- Class C IP addresses are for smaller companies
- The first three octets define the network
- The last octet defines the host
- The first octet begins with 110
57Classes of IP Addresses
- Some addresses are reserved
- 127.0.0.1 (the loopback address) is reserved for
testing - Three ranges are reserved for private networks
- 10.0.0.1 thru 10.255.255.255.254
- 172.16.0.1 thru 172.31.255.254
- 192.168.0.0 thru 192.168.255.254
- One range is reserved for Automatic Private IP
Addressing - 169.254.0.1 thru 169.254.255.254
58Classes of IP Addresses
59Subnet Mask
- The subnet mask defines which portion of the IP
address belongs to the network ID and which part
belongs to the host ID - Expressed as a 32-bit number starting with 1s and
ending with 0s - 1s represent a network ID bit and 0s represent a
host ID bit - For example, 11111111.00000000.00000000.0000000
means that the first 8 bits define the network ID
and the last 24 bits define the host ID - It is associated with an IP address
60TCP/IP Services
- TCP/IP is an entire suite of protocols that
offers TCP/IP Services such as - Hypertext Transfer Protocol (HTTP) used on the
World Wide Web - Telnet used to access remote systems
- Ping to check communication
- TCP/IP is used to link multiple networks (Local
Area Networks or LANs) with other networks to
form an entire Wide Area Network (WAN) - Routers are used to route traffic among the LANs
61PING, LAN and WAN
62TCP/IP Settings
- IP address
- Subnet Mask
- Default Gateway
- The address of a machine (usually a router) that
will deliver messages to hosts outside of your
local segment or subnet
63TCP/IP Settings
- Domain Name Service (DNS)
- To reach any host on a TCP/IP network you need to
know the IP address - Instead of remembering IP addresses you may
simply remember a user-friendly name - DNS is a table that equates user-friendly names
to actual IP addresses
64TCP/IP Settings
- Dynamic Host Configuration Protocol (DHCP)
- Instead of manually configuring the
TCP/IP settings on each computer
(static settings), you may
configure one computer to manage
the assignments for you - Computers that handle this use DHCP and
are called DHCP servers - On the client computer just choose
to Obtain an IP address
automatically
65TCP/IP Settings
- Windows Internet Name Service (WINS)
- Enables Windows network names to be correlated to
IP addresses (like DNS does for Internet names) - Define the IP address of the WINS server
- Windows 2000/XP uses a dynamic DNS instead of
WINS
66TCP/IP Tools Ping
- Ping
- Tests connectivity to a remote host
67TCP/IP Tools WINIPCFG
- WINIPCFG
- Displays your TCP/IP settings in Windows 9x/Me
- Release and Renew allows you to get new TCP/IP
information from a DHCP server
68TCP/IP Tools ipconfig
- IPCONFIG
- Displays your TCP/IP settings in Windows
NT/2000/XP - Release and Renew allows you to get new TCP/IP
information from a DHCP server
69TCP/IP Tools nslookup
- NSLOOKUP
- Determines the name of a DNS server among other
things - Type exit to return to the command prompt
70TCP/IP Tools tracert
- TRACERT
- Shows the route a packet takes to its destination
71TCP/IP Tools APIPA
- Automatic Private IP Addressing (APIPA)
- When a client cannot obtain an IP address
automatically, Windows 2000/XP will automatically
assign its own IP address from the range
169.254.0.0 thru 169.254.255.254 with a subnet
mask of 255.255.0.0 - APIPA is of value when a DHCP server is not
available it allows the hosts on the LAN to
talk to each other even though they cant reach
anyone outside their LAN
72Sharing Drives and Folders
- To share a drive or folder, alt-click it and
select Sharing - Share name is the name others will see on the
network - Windows 9x/Me allows you to define what a user
may do Read Only, Full, or Depends on Password - Windows NT/2000/XP using NTFS-formatted drives
allows for much greater and precise control - Set the network (Sharing tab) permissions to Full
Control - Then use NTFS permissions (Security tab) to
exercise more precise control over who accesses
the shared resource and how they access them
73Sharing Drives and Folders
74Accessing Shared Resources
- Access shared drives or folders using Network
Neighborhood (Windows NT and 9x) or My Network
Places (Windows Me, 2000, XP) - You may also map a drive letter to a shared drive
or folder - Windows 2000 allows you to add a network icon
instead of using a drive letter - Windows XP adds a menu option
75UNC
- Universal Naming Convention (UNC) allows you to
access network resources as follows
\\SERVER1\FREDC
Computer name
Share name
76Sharing Printers
- To share a printer, just alt-click on the printer
and choose Sharing - To access the printer, use the Add Printer icon
and select Network printer instead of Local
printer
77Installing and Configuring a Wireless Network
78Introduction
- Wireless networks are growing in popularity
- Instead of cables, wireless networks use either
radio waves or beams of infrared light to
communicate with each other - Most of todays wireless networks are based on
the IEEE 802.11 standard
79Infrared Connections
- Infrared transceiver ports are standard on many
portable computer, PDAs, and high-end printers - Used to connect local devices to each other
without using a cable
80Wireless Networking Components
- Connection components for wider access
- PCI cards that accept wireless PC cards
- External USB wireless NICs
81Wireless Access Point
- Wireless Access Point (WAP)
- Acts like a hub to the wireless hosts in the area
82Wireless Networking Software
- Wireless devices use the same networking clients
and protocol as wired networks - Use CSMA/CD but have difficulty detecting data
collisions - Another option is using Request to Send/Clear to
Send (RTS/CTS) where the sending node issues an
RTS to the receiving node, who replies with a CTS - Wireless networking software is PnP
- Use a utility (usually provided with the wireless
NIC or built into Windows) to configure the
Service Set Identifier (SSID), or network name
83Wireless Configuration Utility
84Wireless Network Modes
- Ad hoc Mode
- Each wireless node is in direct contact with each
other in a decentralized free-for-all - Form an Independent Basic Service Set (IBSS)
- Called peer-to-peer mode
- Good for a few computers or temporary network
85Wireless Network Modes
- Infrastructure Mode
- Use one or more WAPs to connect wireless nodes to
a wired network segment - A single WAP is called a Basic Service Set (BSS)
- Additional WAPs create an Extended Basic Service
Set (EBSS)
86Wireless Networking Security
- Service Set Identifier (SSID)
- Configure a unique SSID or network name
- Each node needs to have the same SSID
- Not very secure but better than nothing
- MAC Filtering
- Filtering based on each hosts MAC address burned
into their NIC - Creates a type of accepted user
87Wireless Network Security
- Wireless Equivalency Privacy (WEP)
- Encrypts data using 40-bit or 104-bit encryption
- Provides authentication based on MAC addresses
but not users - Encrypts only OSI layers 1 and 2
- Wi-Fi Protected Access (WPA)
- User authentication using the Extensible
Authentication Protocol (EAP) - Uses encryption key integrity-checking
- IEEE 802.11i
- Upcoming new security standard
88Wireless Networking Standards
- IEEE 802.11-Based Wireless Networking
- Wireless Ethernet standard using spread-spectrum
radio waves - Broadcast and receive at 2.4 GHz
- 802.11a uses 5 GHz
- The original standard has been extended to form
the Shared Wireless Access Protocol (SWAP) used
in HomeRF networks
89802.11 Standards
90Wireless Network Standards
- Infrared Wireless Networking
- Simple way to share data without adding any
additional hardware or software - Uses the Infrared Data Association (IrDA)
protocol - Included in Windows 95 and higher
- Line-of-sight required
- No authentication or encryption
- But then you cant be over 1 meter away
91Configuring Wireless Networks
- Physically installing a wireless NIC is the same
as installing a wired NIC - Install the wireless network configuration
utility to configure additional parameters - Windows XP has configuration parameters built-in
- The more important issue is authentication and
security
92Configuring Wireless Networks
- Wi-Fi and HomeRF
- Ad hoc
- Each wireless node needs to be configured with
the same network name (SSID) - May need to select a common channel
- Configure unique host IP addresses
- Configure File and Printer Sharing
- Infrastructure modes
- Requires a wireless access point (WAP)
- All nodes need to be configured with the same
SSID - Configure the WAP with clients that match the
chosen options
93Configuring Wireless Networks
94Configuring Wireless Networks
- Configuring a Wireless Access Point (WAP) is
usually done through a web browser - Enter the WAPs default IP address (see your
documentation or try 192.168.1.1) in your browser - Enter the default administrative password (in
your documentation) to log in - The next few slides show some screen shots of the
configuration pages
95Configuring Wireless Networks
96Configuring Wireless Networks
97Configuring Wireless Networks
98Configuring Wireless Networks
- Encryption screen on client wireless network
adapter configuration utility
99Configuring Wireless Networks
- Infrared
- About the only thing to do is to confirm in your
network protocol configuration screen that you
have the IrDA protocol installed and enabled - To transfer files just alt-click the file in
Windows Explorer and choose Send To Infrared
Recipient - To network two computers just choose Connect
Directly to Another Computer when choosing the
connection type
100Troubleshooting Networks
101Troubleshooting Networks
- Verify the symptom
- Talk with the use to try to get a solid
description of the symptoms - When did it happen?
- Does it happen a boot, when the OS loads, or
after the system has been running for awhile? - What has changed?
- Try to find out if anything has changed even
recent changes before the problem began occurring
102Troubleshooting Networks
- Check the environment
- Heat, humidity, dirt
- What OS? What applications? Do others use the
computer? - Reproduce the problem
- If a problem happens only once, its not a
problem - Otherwise, try to make the problem happen again
- Isolate the symptom
- With hardware remove parts until you find the
suspect one - With software remove background programs or boot
into Safe Mode
103Troubleshooting Networks
- Separate hardware from software
- Replace the suspect hardware with known good
hardware if that doesnt solve the problem,
then its probably software related - Uninstall the suspect software and reinstall it
- Install the latest patch or upgrade
- Check for viruses
- Research
- Use the Internet as a great tool
- Make the fix and test
- Keep track of what you did so that you may return
to the previous state if the fix does not work
104Mikes Four-Layer Model
- Hardware
- Check the hardware starting with the physical
layer - Protocols
- Is it installed and configured properly?
- Network
- Servers and non-servers
- Check users and groups, share names
- Shared resources
- Make sure the resource has been properly shared
- Check the access allowed
105Bluetooth
- Bluetooth is designed to replace all those cables
connecting peripheral devices together
keyboards, mouse, printer, speakers, scanner - Acceptable for quick file transfers
- Acceptable for browsing the Internet
- Hardware comes integrated on most new portable
electronic devices or as an internal or external
adapter - Configuration is PnP
- Bluetooth access points use a web browser for
configuration
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