Download Networking.2

Networking
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Section Objectives
After completing this section you will be able to:
 Differentiate between peer-to-peer and server-based networks
 Identify commonly used network topologies
 Compare and contrast types of network cabling
 Explain the differences between various network access methods
 Explain how Ethernet works
 Identify OSI model layers and the network devices that work at each layer
 Articulate commonly used network protocols
 Define the purpose and identification of a MAC address and an IP address
 Apply IP addressing concepts
 Define the purpose of DHCP, WINS, and DNS
 Configure an NIC for network connectivity
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Networking Overview
 A network is two or more devices capable of communicating
and sharing resources between them.
 Types of networks:
– PAN (Personal Area Network) – Personal devices such as PDAs can
communicate in close proximity through a wired or wireless network.
– LAN (Local Area Network) – A group of devices sharing resources in a
single area such as a room or a building.
– MAN (Metropolitan Area Network) – Connectivity of sites within a city.
– WAN (Wide Area Network) – Two or more LANs communicating, often
across large distances. The most famous WAN is the Internet.
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Types of Local Area Networks
 Types of LANs:
– Server-Based Network (client-server network)– A type of
LAN wherein users login to a controlling computer, called a
server and is more secure. These networks normally consist
of 10 or more computers.
– Peer-to-Peer Network – A type of LAN wherein each
computer user acts as a server. Each computer stores
password and sharing information for its own resources.
Usually has fewer than 10 computers.
 NOS (Network Operating System) – Special operating system
on a server containing utilities for managing users, resources,
and security.
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Types of Local Area Networks
Server-Based network
Network – Figure 15.1
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Types of Local Area Networks
Peer-to Peer network
Network – Figure 15.2
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Network Topologies
 Physical network topology – How the network is
wired.
 Ethernet – The most common type of network.
 Hub – A device that allows multiple device
connections. Hubs are not as intelligent as switches.
 Switch – A switch looks at each data frame as it comes
through each port.
 Star Topology – Most common network topology.
Each device connects to a central hub or switch.
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Network Topologies
Hub (switch)
Network – Figure 15.4
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Network Topologies
Star topology
Network – Figure 15.5
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Network Topologies
Network topologies
Network – Table 15.2
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Network Media Overview
 Cable or air are used as mediums for transporting
network data.
 The most common types are twisted-pair and fiberoptic, although coax is still used in some old networks.
 Wireless networks use the air to transmit data over
radio frequencies.
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Copper Media
 Twisted-Pair Cable – Network cable of eight copper wires twisted into four
pairs to prevent crosstalk.
– UTP (Unshielded Twisted-Pair) – Most common network cable that
comes in different categories for different uses. Categories 5e and 6. It is
unshielded and more susceptible to interference.
– STP (Shielded Twisted-Pair) – Same as UTP cable, but with extra foil to
prevent outside noise from interfering with data on the cable.
 Crosstalk – Where signals from one wire interfere with the signal on an
adjacent wire.
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Network Cabling
UTP cable
Network – Figure 15.6
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Copper Media
 Plenum cable is treated with Teflon or fire retardant materials
to reduce the risk of fire. It produces less smoke and is less
toxic when burning.
 PVC (polyvinyl chloride) – Cable with a plastic cable insulation
or jacket. PVC is an alternative to Plenum cable.
 Coaxial Cable (coax) – Type of copper network cabling used in
older Ethernet networks as well as mainframe and
minicomputer connections. Has a single, center wire conductor
with an outer braided shield.
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Network Cabling
UTP wiring standards
Network – Figure 15.7
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Network Cabling
RJ-45 pin 1 assignments
Network – Figure 15.8
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Network Cabling
Coax cable with connector
Network – Figure 15.9
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Fiber Media
 Fiber-Optic Cable – An expensive network cabling made of
plastic or glass fibers that carry data in the form of light pulses.
Most often used to connect network devices such as switches
together into a network backbone or for connecting networks
together in a WAN. More secure and not affected by crosstalk
or other interference like copper cable.
– Single-Mode – A type of fiber-optic cabling that sends one light beam
down the cable. Used for longer distance applications.
– Multi-Mode – A type of fiber-optic cabling that allows multiple light
signals to be sent along the same cable. Used for shorter distances.
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Network Cabling
Fiber-optic cable
Network – Figure 15.11
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Access Methods
There are standard rules by which computers on a network must
adhere to in order to communicate. These rules are known as a
common access method.
 CSMA/CD (Carrier Sense Multiple Access/Collision Detect) – A common
access method used by Ethernet.
 Token Passing – The common access method used by fiber and Token Ring
networks.
 Token – Small data packet passed from one networked device to another in
a ring topology.
 CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) – A
common access method used in wireless and Apple networks.
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Ethernet Issues and Concepts
 Two types of transmissions used in Ethernet networks:
 Half Duplex – Allows either the sending or the
receiving device to send data, one device at a time.
Data can travel both ways on a cable, but not at the
same time.
 Full Duplex – Allows the sending and receiving
device to send data simultaneously. Data can travel
both ways on a cable at the same time.
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Network Standards
IEEE 802 standards
Network – Table 15.5
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OSI Model
 OSI Model (Open Systems Interconnect) – A standard
for information transfer across a network that was
developed by the International Standards Organization.
The model has 7 layers.
– Physical Layer – Layer 1 of the OSI model that defines how
bits are sent and received across the network without regard
to their structure.
– Data Link Layer – Layer 2 of the OSI model that accurately
transfers bits across the network by encapsulating (grouping)
them into frames.
– Network Layer – Layer 3 of the OSI model that coordinates
data movement between two devices on separate networks.
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OSI Model
– Transport Layer – Layer 4 of the OSI model that determines details on
how the data is sent, supervises the validity of the transmission, and
defines protocol for structuring messages.
– Session Layer – Layer 5 of the OSI model that manages communication
and administrative functions between two network devices.
– Presentation Layer – Layer 6 of the OSI model that defines how data is
formatted, encoded, converted, and presented from the sender to the
receiver, even though different computer language is used.
– Application Layer – Layer 7 of the OSI model that defines how
applications and the computer interact with a network, and negotiates
services such as authentication, error recovery, and quality of service.
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OSI Model
ISP (Internet Service Provider) – A vendor
that provides connection to the Internet.
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OSI Model
OSI model layers
Network – Figure 15.15
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OSI Model
OSI peer communication
Network – Figure 15.16
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OSI Model
OSI model
Network – Table 15.6
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Networking Protocols
 Network Protocol – Data communication language.
– TCP/IP (Transport Control Protocol / Internet Protocol) –
The most common network protocol used by most companies
and home users as a standard protocol. Used to access the
Internet.
– IPX/SPX (Internetwork Packet Exchange/Sequenced Packet
Exchange) – Original protocol used for connecting to Novell
networks. Now TCP/IP is the standard protocol used.
– NetBEUI (NetBIOS Enhanced User Interface) – Is a nonroutable protocol used in simple networks.
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Network Addressing
Network devices have to be able to identify each other in order
to communicate across a network. They do this through various
network addressing schemes.
 MAC Address – A 48-bit unique number that is burned on the
ROM chip of the NIC.
 IP Address – It is a 32-bit binary number with groups of eight
bits separated by a dot.
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IP Addressing
 Network Number – Portion of an IP address that
represents which network the computer is on.
 Host Number – Portion of an IP address that
represents the specific network device.
 Broadcast Address – IP address used to communicate
with all devices on a particular network.
 Subnet Mask – A number the computer uses to
determine which part of an IP address represents the
network and which portion represents the host.
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Network Addressing
IP Addressing (network and host portions)
Network – Figure 15.17
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IP Addressing
IP addressing (two network example)
Network – Figure 15.18
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IP Addressing
IP addressing information
Network – Table 15.9
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DUN (Dial-Up-Networking)
 DUN (Dial-Up Networking) – A remote computer that dials
into the Internet or a corporation using a modem.
 PPP (Point-to-Point Protocol) – A connection-oriented that
encapsulates data for transmission over various connection
types.
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Dial-up Networking
Network connections
Network – Table 15.10
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Internet Software
Once a connection is established to a remote network
there are several program types that are useful for
accessing data.
 Browser – A program that views web pages across the
Internet. The common browsers include Internet
Explorer, Netscape Navigator, and Mozilla FireFox2.
 Plug-in – An application, such as Macromedia Flash,
designed to work with the browser.
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Wireless Networks Overview
Wireless Networks – Transmit data over air
using either infrared or radio frequencies.
Wireless networks operate at layers 1 and 2 of
the OSI model.
Bluetooth – Wireless technology for PANs.
Piconet – A small network.
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Wireless Networks Types
 There are two main types of wireless networks:
– Ad hoc – Also known as peer-to-peer or IBSS (Independent
Basic Service Set) – An ad hoc wireless network is when at
least two devices such as two computers have wireless NICs.
– Infrastructure – Wireless network that connects multiple
wireless network devices through an Access Point.
 There are three major types of wireless NICs: PC
Card, USB, and PCI.
 Access Point – Is similar to a network hub and
connects wireless network devices.
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Wireless Networks Types
 BSS (Basic Service Set) – Configuration when multiple devices
connect to an access point.
 ESS (Extended Service Set) – The network design when
multiple access points connect to the same main network.
 SSID (Service Set Identifier) – A set of 32 alpha numeric
characters used to differentiate between wireless networks.
 The channel ID (frequency) between the Access Point and the
adapter must match for communication to occur.
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Wireless Networks Types
802.11b/g frequency channels
Network – Table 15.11
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Wireless Network Standards
Modulation – When data is added to a carrier
signal.
IEEE 802.11 standards
Network – Table 15.13
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Wired or Wireless NIC Installation
When installing a NIC, you must configure the
following prior to connecting to the network:
Determine that an appropriate port, slot, or
integrated wireless NIC is available.
Install the appropriate NIC drivers.
Assign the computer an appropriate name and a
workgroup or domain name.
Configure the network protocol and client.
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Configuring Networking
Some key terms to understand when configuring computers for
networking are:
 DHCP (Dynamic Host Configuration Protocol) – A method to
automatically assign IP addresses to network devices from a
pool of IP addresses. A computer requests an address from
another device running DHCP, usually a server, receives it, and
joins the network.
 Default Gateway – The IP address of the Layer 3 device, such
as a router, that is directly connected to its immediate network
and acts as a doorway or director to other remote networks.
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Configuring Networking
 DNS (Domain Name System) Server – Application on a
network server that translates Internet names into IP addresses.
 URL (Universal Resource Locator) – A method of accessing
Internet resources by using a simple, easily remembered name
assigned to an IP address.
 WINS (Windows Internet Naming Service) Server – Keeps
track of IP addresses assigned to a specific computer name. A
user can type in a computer name to connect and the server will
translate it to the computer’s IP address.
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Wired or Wireless NIC Installation
Before installing a wireless NIC, be sure to
confirm the basic configuration settings for the
wireless network.
Install the NIC by following the manufacturer’s
instructions.
Configure the basic wireless network settings to
begin communication on the network.
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Configuring Networking
Default gateway
Network – Figure 15.41
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Network Troubleshooting
Some commands that are useful to a technician when
diagnosing network connection issues:
 Ping – A command used to test TCP/IP communications and determine
if a network path is available. You can type ping and either a domain
name or IP address and connectivity to that device will be tested.
 IPCONFIG – A command used with Windows XP and 2000 to see and
modify the current IP settings.
 NSLOOKUP – An NT, 2000, XP and 2003 Server troubleshooting tool
that displays network domain names and their associated IP addresses.
 Tracert – A command that displays the path a data packet takes through
a network, thus allowing one to see where a fault occurs in larger
networks.
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Network Troubleshooting
Sample network configuration
Network – Figure 15.47
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Network Troubleshooting
IPCONFIG and IPCONFIG /ALL
Network – Figure 15.48
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Network Terminology
Networking Terms and Acronyms To be
Familiar With:
Backbone
Broadband
FDDI
HTML
Packet
TCP
Bandwidth
E-mail
Frame
HTTP
POP
Telnet
Baseband
Fast Ethernet
FTP
Infrared
SNMP
UDP
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Sharing
Network share – A folder that has been shared
and can be accessed from a remote computer.
UNC (Universal Naming Convention) – A
standard way of naming computers and shared
resources on a network. Used at the command
prompt to obtain network shares.
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Email
 SMTP (Simple Mail Transport Protocol) – is a protocol used
for sending and receiving email. Settings for configuring email
can be obtained from the network administrator or the ISP being
used to connect to the Internet.
 POP3 (Post Office Protocol) and IMAP (Internet Mail Access
Protocol) are methods used to receive email to a person’s
account.
 MAPI (Messaging Application Programming Interface) –
Microsoft’s proprietary alternative email protocol.
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