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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

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Network Architecture• Network designs:

– Individual PC controlled, local control• Peer-to-peer (P2P)

– Central control• Client/server

Peer-to-peer

Client/server

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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

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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.

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PANs, HANs and LANs

• Personal Area Network (PAN) – Connects devices close to one person

(smartphones, tablets, with WiFi or Bluetooth)

• Home area network (HAN)– Connects digital devices within a home

• Local area network (LAN)– Nodes are within a small geographic region

• Schools• Small businesses

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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 hardware • Network Software

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Transmission MediaOverview

• Provides communications channel between nodes• Forms of media (wire):

– Twisted pair (copper)• telephone• Ethernet

– Coaxial cable(copper)– Fiber-optic (FIOS)

• Plastic or glass fibers– Radio wave (wireless)

• Bandwidth:– Data transfer rate (max)– Throughput (actual speed)

Run this slide to see the pictures!

• Names for Ethernet wire:– UTP – unshielded twisted pair, – “Twisted copper pairs”

• It has 4 pairs of wires (8 total wires), twisted to reduce interference; RJ-45 connector

• Compare to telephone wire which has 2 pairs of copper wires; RJ-11 connector

• Don’t run Ethernet lines longer than 328 ft, don’t bend wire a lot, lie along edges of room.

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Transmission MediaEthernet wire Factoids

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• Older: 100 M bps• Current -- for home: “1 Gigabit” = 1 G bps= 1000 M bps • Current -- for business: 10 G bps• Wired 1G bps ( 1 Gigabit) networks are

Transmission MediaEthernet wire speed standards

FYI the wire pictured here is NOT even Ethernet wire!!

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Transmission MediaSpeed of common transmission media

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Network Hardware Network Adapters (1)

• Network adapter – a component on each node of the network allowing it to connect and communicate with other network nodes.

• Types:– Wired network adapter (contains Ethernet port!)– Wireless network adapter (no port – its wireless!)– Current standard is that most laptops have wired

and wireless network adapters; desktops usually just wired network adapter unless specially ordered

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• Adapter or card, interchangeable words; Types:– Internal version called network card = Network

interface cards (NIC) – External version called network adapter (one type

is USB adapter) – Same terminology used with wireless network card

variety

• Wired network card standard speed now is one Gigabit (1 G bps)

Network Hardware Network Adapters (2)

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Pictures of network cards and adapters:– Internal card = Network interface cards (NIC) (A)– External laptop network card; “express card” ( –

goes into slot in laptop (B)– External card = network adapter (one type is USB

adapter) (C) – Wireless network card(left picture)

A

B

C

Network Hardware Network Adapters (3)

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Network Hardware Network Navigation Devices

• Router: Routes data between 2 networks• Switch: Routes data across one network. Traffic cop• A router (or wireless router) usually …

– Contains the switch and– Maybe the modem too– has wired and wireless capability; comes with 4

ports– In other words, one device contains all necessary

capabilities.• extender– Amplifies signal across longer wires

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The common (wireless) router

Router allows for wired and wireless connections; ports for wired connections

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Networking Software • Peer-to-Peer Software:

• Built into operating systems that support networking

–Windows XP, Vista, Windows 7–Mac OS , Linux

• Client/Server Software (central services and security)

• Network operating system (NOS) software–Windows Server 2008–SUSE Linux Enterprise

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Home network Requirements

1. Network adapter (wireless network adapter) - each node requires one to connect to router.

a) Wired nodes connect w/ Ethernet wire; Wireless nodes connect with radio frequencies (RF)

2. Modem (DSL or cable)3. Wireless router -- or gateway ( a wireless router

also has ports for wired computers)4. Optional device –Wireless Access Point (or

extender) – if reception is poor in parts of network5. Picture next page

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Home network picture

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1. Verify that each node on the network has a network card/adapter

2. Connect coaxial cable to cable modem (or telephone line to DSL modem). Connect PC to modem

– Verify that Internet is live on PC. If live, then connect modem and router together. And disconnect PC above and reconnect to router.

3. Connect all other nodes to router (laptops, desktops, networkable printers, etc.)

Home network Create the network 1/2

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4. Turn on the following in this order , waiting a few minutes in between:

a. Cable/DSL modem b. Router (Then wait a few minutes.)c. All computers other nodes (PCS, printers, etc)

5. Open Control Panel> Network and Sharing. – With wired connection (and Windows 7), you should

be connected to home network automatically– With wireless connection, click on Connect to a

network option, (and enter security pass phrase if you already secured your router, see 2 slides ahead.)

Home network Create the network 2/2

IEEE standards• IEEE – Institute of Electrical and Electronic Engineers.• Set electronic standards and for Ethernet networks • 802.3 standard – wired networks• 802.11 standard – wireless networks ranked from

older to newer standards:– 802.11a, b, g (older)– 802.11n – 802.11ac (newest)– (802.11ad or WiGig. Not for home networks) (newest)

• When wires/hardware/technologies are paired and have differing standards, the older standard prevails, (backwards compatibility)

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Wireless Networks• Wireless router …

– Can connect up to 253 wireless– Contains a transceiver (transmits and receives

signals) and antenna

• Wireless – Interference - can come from cinderblock, other

building materials, other electronic devices, neighbors’ networks, magnetic or electrical sources, between network equipment.

– Compared to wired, wireless has lower throughput as consequence of interference

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Wireless NetworksSECURE YOUR WIRELESS ROUTER:

1. Change SSID to unique one (and/or turn off broadcasting of it.)

2. Change default username from “admin” to a secure username you desire. And change the password.

3. Enable security protocol (WEP or newer WPA2)4. Restrict access via MAC filtering (MAC =Media Access Control )

5. Limit your signal range.6. (Apply firmware upgrades – technical step)

Other (optional)• New devices, televisions 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

• Home Network Server (“server” in the name yet still used on P2P; for media files)

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