Mid Lec 5 Cont1 Networks

8/8/2019 Mid Lec 5 Cont1 Networks

1/33

NETWORK

Are multiple computers linked together to make simultaneousinformation sharing and exchange by multiple users. Computer

network makes it possible for its connected users to share tools,

resources and information. Resources include data, printers, internet

servers and software applications.

3 Basic Network Categories

1. Local Area Network (LAN)

2. Metropolitan Area Network (MAN)

3. Wide Area Network (WAN)


2/33

NETWORK

1. Local Area Network

(LAN)

The smallest of the 3

network types

Consists of PCs

connected together

within a limited area

(same building, floor or

department)

Good for small to

medium businesses


3/33


4/33

NETWORK

2. Metropolitan Area

Network (MAN)

A network that spans

no more than 50 miles.It is designed to

connect LANs spanning

a town or city


5/33


6/33

NETWORK

3. Wide Area Network

(WAN)

Used to distribute

information thousand ofmiles among thousand

of users.

A WAN spans cities to

countries and even

continents

WANs can beconnected to existing

networks to form an

inter-network (internet)


7/33


8/33

Network Terms

Network Server a powerful computer whose sole purpose is to servenetwork clients. Servers run network controlling software and provideworkstations with requested resources.


9/33

Hosts any computer whether mainframe, server or even a PC that acts

as an information source on a network. Essentially, any computer that

has an TCP/IP network address can be a host. Even a workstation can

be a host because it can act as a network information source.


10/33

Peers any computer sharing the same protocol layer with another

computer. When two computers share resources, security levels and

user group, they are considered peers.


11/33

Workstation is any network computer that connects to and requests

resources from a network


12/33

Protocol refers to the specific standards governing the sending ands

receiving of data. Data transmission system follow predetermined rules

so data travels in universally accepted manner, because there are

different computer languages, protocols have been developed.


13/33

2 Types of Network Architecture

1. Peer to Peer no

centralized computer oversees

the networks, no server, and

computers simply connect with

each other in a workgroup toshare files, printers and

Internet access


14/33


15/33

2 Types of Network Architecture

Client / Server use a

network OS to manage the

entire network. There is

usually a Domain Controller,

which all of the computers logon to. WSs requests

information- a file, for example-

from a server. The server

provides the requested

information. This server can

provide various services,including centrally routed

Internet Access, mail, file

sharing and printer access.


16/33


17/33

Network Media any material that transport data in any way orform. When data is sent over a network, it travels through wires,

cables or cords. The physical means through which a network datatravels is called media

RJ45 CONNECTOR


18/33

1. UTP (Unshielded Twisted Pair) the least expensive and mostpopular network media.

Advantage: Special coating that shrinks in high fire temperature

eliminating toxic fumes Disadvantage: lack of insulation, which makes the cable susceptible

to electrical interference


19/33

2. STP (Shielded Twisted Pair) is twisted, plastic coated, sheath-wrappedcopper wire. The main difference of UTP and STP is the STPs aluminum orpolyester shielding surrounding individual wires allowing STP to reduce oreliminate interference


20/33

3. Fiber Optic are thin, glass strand that carry light waves and are wrapped by an

outer, protective sheath. Interpreted by computer as data, the light waves in a

fiber optic can travel great distances and deliver vast amounts of data. Fiber optic

cabling systems are extremely powerful and efficient but quite expensive


21/33

4. Coaxial cable commonly used by cable TV. A center cable is insulatedby plastic or foam, wrapped in a copper mesh wire and sheathed in aplastic or rubber jacket. Coaxial cable is relatively inexpensive to produceand install.


22/33

Network Hardware

1. Network Interface Card (NIC) a printed circuit board, an adapter

that plugs into the computers motherboard when connected with a

network cable, provides a physical link between your computer andthe network. Its main function is to convert computer data into cable-

transmittable data, and provide a connection to network media


23/33

2. Network Hub a hardware device that all PCs on a network are

connected to by cabling. The hub manages receiving and

transmitting data from network devices. It allows data to flow on and

off the network between printers, computers and other devices bysharing the lanes of traffic


24/33

3. Wireless Hub it works by converting network signals to radiofrequencies and back to network signals at the receiving computer


25/33

Kinds ofHUBS

Standalone Hub are single products with a number of ports. The

least expensive kinds of hub. Typically with fewer than 12 users per

LAN


26/33

Stackable Hubs work just like standalone hubs, except that several

of them can be stacked (connected) together. When they are

connected together, they act like a modular hub because they can

be managed as a single unit


27/33

ModularHubs popular in networks because they are easily expandedand always have a management option. Purchased as a chassis or cardcage with several card slots, each of which accepts a communicationcard or module. Each module acts like a standalone hub.


28/33

3 Basic HUB Types

1. Passive Hub simply connects various cables

2. Active Hub amplify or boost signals3. Intelligent Hub select which path a specific signal will travel

Active Hub

Passive Hub

Intelligent Hub


29/33

4. Repeater a device that strengthen signals and allow them to stay clear

over longer distance

2 Basic Types of Repeater

1. Amplifiers strengthen an incoming signal to make the signalstronger and more powerful, unfortunately the accompanying noise is

also amplified


30/33

2. Signal Generators a device that work by receiving and rebuilding

signals, then re-transmitting the signal with fresh power


31/33

Network Bridge divides network into smaller, more manageable sections

helping reduce network traffic. Data signals arriving at a bridge contain

information about their destinations. The network bridge allows only specific

information to travel over certain paths. When a signal arriving at a bridge does

not posses the appropriate address it is filtered out completely.


32/33

Network Switch makes asimple do / dont decision onwhich packets to send acrosstwo segments they connect. It

helps determine how datamoves over very largenetworks. It works like astoplight at a busy intersection.It allows data to travel in its ownlane of traffic.

3 Types of Network Switches1. Circuit Switch establish asingle, direct data route

2. Message Switch storedata, forwarding the informationwhen possible

3. Packet Switch combinecircuit and message switchingtechnology dividing longmessages into smaller onescalled Packages


33/33

Router a device that forwards data packets between Local or Wide

Area Network groups. Using routing tables and protocols, routers

read a signals network address and decides its most expedient

route

Documents

Mid Lec 5 Cont1 Networks