Chapter 7 - Networking Fundamentals
• Computer network:
– Two or more computers connected together
• Each is a Node (other nodes: printers, network
devices, such as a router, etc
• Benefits of a network:
– Sharing resources
– Transferring files
1
Network Architecture
• Network designs:
– Individual PC controlled, local control
• Peer-to-peer (P2P)
– Central control
• Client/server
Peer-to-peer
Client/
server
2
Peer-to-Peer Networks
• Use for < 10 computers
for home and small office
networks
• Nodes communicate
with each other:
– Peers
• Share peripheral devices:
– Printers
– Scanners
3
Client/Server Networks
• Used for > 10 computers
• Client computers:
– Users
• Server computers:
– Provide resources to clients
– Central network control
• Internet
– A large, multiserver,
multiclient network.
4
HANs and LANs
• Home area network (HAN)
– Connects digital devices within a home
• Local area network (LAN)
– Nodes are within a small geographic region
• Schools
• Small businesses
5
WANs and MANs
• Wide area network (WAN)
– LANs connected over long distances
• A few miles to thousands of miles
• Uses telecommunications lines
• Metropolitan area network (MAN)
– Provides access within a specific geographic
region, such as a city
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•
•
•
•
Network Components
Transmission media
Network adapters
Navigation devices
Software
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Transmission Media
• Provides communications channel between nodes
• Forms of media (wire):
– Twisted pair (copper)
• telephone
• ethernet
– Coaxial cable(copper)
– Fiber-optic (FIOS)
– Radio wave (wireless)
• Bandwidth:
– Data transfer rate (max)
– Throughput (actual speed
8
Ethernet wire
• UTP – unshielded twisted pair, made of copper
• 4 pairs of wires (8 total wires) are twisted to
reduce interference (static); RJ-45 connector
• Compare to telephone wire which has 2 pairs
of copper wires; RJ-11 connector
• connector Max line 328 ft, don’t bend wire a lot, lie along
edges of room.
• Wires, and hardware need to be at same standard
• 1000 M = 1G
It’s
6a, not 7,
in Tech In
Action 8e
9
Network Adapters (1)
• A device that enables communicate between
nodes on network
• Types:
– Wired network adapter (contains Ethernet port!)
– Current standard is that most laptops have wired
and wireless network adapters; desktops usually
wired network adapter
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Network Adapters (2)
• Adapter or card, interchangeable words; Types:
– Internal card = Network interface cards (NIC) (A)
– Network card for laptop (B)
– External card = network adapter (one type is USB
adapter) (C)
– Wireless network card(left pic)
• Enables communication between nodes
C
A
B
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Network Navigation Devices
• Router: Routes data between 2 networks
• Switch: Routes data across one network
• What is referred to as a router (or wireless router)
these days…
– Contains the switch and
– Usually contains the modem too
– Usually has wired and wireless capability; comes
with 4 ports
– In other words, one device contains all necessary
capabilities.
• Repeater –Amplifies signal across longer wires
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The common (wireless) router
Router allows for
wired and wireless
connections; ports
for wired
connections
13
Networking Software
• Peer-to-Peer Software:
• Built into operating systems that support
networking
– Windows XP, Vista, Windows 7
– Mac OS , Linux
• Home Network Server (“server” in
the name yet still used on P2P; for media files)
• Client/Server Software (central services and
security)
• Network operating system (NOS) software
– Windows XP Professional,(Vista Ultimate?)
– Windows Server 2008
– SUSE Linux Enterprise
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Wired, wireless speeds
Comparing the Major Types of Home Networks
Wired
Ethernet
Power-Line
Wireless
802.11g
Wireless
802.11n
Maximum data transfer rate
(bandwidth)
100 Mbps to
1 Gbps
200 Mbps
54 Mbps
540 Mbps
Relative installation and
equipment costs for networking
two computers
$
$$
$
$$
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Wired/wireless Ethernet Network 1 of 2
1. Each computer/node requires a
network adapter or wireless
network adapter to
Ethernet
communicate w/ router.
–
–
Telephone
Wired nodes are connected to
each other with Ethernet wire
Wireless nodes connect with
radio frequencies
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Wired/wireless Ethernet Network 1 of 2
Continued from previous slide…
2. Wireless router -- or gateway ( a wireless
router also has ports for wired computers)
2. Modem (DSL or cable)
3. Optional device –Wireless Access Point – if
reception is poor in parts of your house
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Wireless - other
•
Wireless router …
– Connects up to 253 wireless, yet they SHARE
BANDWIDTH
– Contains a transceiver (transmits and receives
signals) and antenna
• Wireless interference:
– sometimes wireless networks have interference
from cinderblock, other building materials, other
electronic devices,
• Wired 1G bps (Gigabit) networks are faster (for
video files, multi-player games). Otherwise consider
wired for media devices (TV, etc)
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IEEE standards
• IEEE – Institute of Electrical and Electronic Engineers.
• Set electronic standards including those for Ethernet
networks
• 802.3 standard – wired networks
• 802.11 standard – wireless networks:
– 802.11a, b ( older and < 54 M bps)
– 802.11g ( = 54 M bps)
– 802.11n ( 540 M bps)
• Rec’d - all components from same manufacturer
• Cards, wires, devices must match to get that
corresponding speed, but backwards compatible
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Configure software for network
discard this slide?
1. Install (verify) network adapters on each
node.
2. Connect cable/DSL modem cable or tele
line to modem and connect PC to modem
(Verify Internet is live).
• If live, connect modem to router instead
(and PC to router too)
Go to next slide…
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Configure software for network -
discard this slide?
3. Connect PC and other nodes (PCs,
networkable printers etc) to router
4. Turn on all equipment in the following
order, wait 1 min after each one:
a. Cable/DSL modem
b. Router
c. All computers other nodes (PCS, printers, etc)
5. Run network wizards, adjust settings for
sharing (Control Panel > Network and
Sharing. Details left out)
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Configuring a Router to
Connect to the Internet
•
•
•
•
Contact ISP for special settings
Access router from Web browser
Enter username and password
Use router’s wizard to set up connection using
settings and info provided by ISP
• Test Internet connection speed
– Speedtest.net
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Secure your wireless network
SECURE YOUR WIRELESS ROUTER:
1. Change SSID to unique one (and/or turn off
broadcasting of it.)
2. Change default username from admin to ___ and
change password.
3. Enable security protocol (WEP or newer WPA2)
4. Restrict access via MAC filtering (Media Access
Control )
5. Limit your signal range.
6. Apply firmware upgrades
7. Others p 326+
23
Other
• Hub – a switch is a smart hub. Hub transmits
signals to all nodes whereas switch transmits
only to requesting nodes.
• New devices, television and related media
devices, now come with network adapters to
connect to your network
• Network attached storage (NAS) – drive
accessible to network for graphic/video files
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