Network Essential

8/3/2019 Network Essential

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Network Fundamentals


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What is Network?

A group of computers and other devices that areconnected by some type of transmission media. Small as two computers connected by a cable in a home,

office

Large as several thousand computers connected bycable, satellite or phone line.


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Why use Network?

Manage or Administer resources on multiplecomputers from a central location

Enable multiple users to share devices andresources such as:

PrintersFaxes

Programs and Files Word Processing

Data Base


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Overview Of Network Hardware

Network has 2 categories: Clients / Workstations

A system or device that make use of shared networkresources.

Servers A computer System that provides and manages sharednetwork resources.

Files

Printers

E-mail

Web pages


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Type of Network

Peer-to-peer

Client/Server Networks.


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Peer-to-peer/P2P Networks

Each system unit acts as a client and a server.

Ideal for small network.

Each system potentially shares resources amongother client systems.

No need dedicated server.

All system unit using various type of OS.


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Advantage & Disadvantage of P2P

Simple to configure

Dont need much

technical expertise Typically less expensive

to setup

Not very flexible

Have less services.

Do not have strongsecurity.

Advantage Disadvantage


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Client/Servers Networks

Sometimes called Server-based network.

A network that using dedicated servers.

Usually use at Medium-sized business

Large businesses

Dedicated server system must using server OS.


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Advantages & Disadvantages ofClient/Server Network

User login accounts and passwords foranyone on a server-based networkcan be assigned in one place.

Access to multiple shared resources

can be centrally granted to a singleuser or groups of users Problems on the network can be

tracked, diagnosed, and often fixedfrom one location.

Servers are optimized to handle heavyprocessing loads and dedicated tohandling requests from clients.

Servers can connect more than ahandful of computers on a network

Using complex &complicated

configuration. Expensive to setup.

Need much technicalexpertise

Advantages Disadvantages


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How to link a Network

Hardware components Network Wiring

NIC

Network Equipment

Software components NIC driver

Services

Protocols

Client Software Server Software

Redirector


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Services

Services = Network operation

Type of services Printing-Print spooler,

DNS

Dynamic Host Configuration Protocol (DHCP) Directory Services- assigned name kepada ip address

Nat check google

Network file System & etc


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NIC driver

Use to run the NIC.

Allow the NIC to work with OS


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Protocols

A standardized way of performing a specificaction. /bahasa komunikasi dalam network

Acts as the language the system will use tocommunicating to each other.

Type of protocols TCP/IP

User Datagram Protocol (UDP)

IPX/SPX

NetBEUI


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Server Software

Allows a system to provide and manage information& services.

Usually have on Server OS.


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Client Software

Allows a system to request services from the systemproviding the resources.


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Redirector

Played by the client software to provide an interfacebetween the resources of the network and thefunctions of the host PCs operating system. Like drive letter S: for network mapping

Shared folder


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LAN , MAN and WAN

LAN Local Area Network

MAN Metropolitan Area Network

WAN Wide Area Network


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Local Area Network (networksetempat)

A network of computers and other devices that is confinedto a relatively small space, such as one building or evenone office

Interconnected and rely on several servers running many

different applications and managing resources other thandata.

Example : A School Network.


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Local area Network


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Metropolitan Area Network

A network that is larger than a LAN and connects clientsand servers from multiple buildings

A MAN may use different transmission technology andmedia than a LAN because of the distance it covers

Example : 2 or more Buildings is ConnectedGunakan fibre optic, satelite


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Metropolitan Area network


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Wide area Network

A network that connects two or more geographicallydistinct LANs or MAN

WAN carry data over longer distances than MANWANs require slightly different transmission methods and

media and often use a greater variety of technologiesthan MAN

Most MAN can also be described as WAN kalau jarakjauh

WAN commonly connect separate offices in the sameorganization, whether they are across town or across the

world from each other


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Wide Area Network


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Topologies

Physical layout of computer networkBus

Star

Ring

Hybrid


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Bus Topology

Consists of a single cable connecting all nodes (PC) on anetwork without intervening connectivity devices

The single cable is called bus and can only support onechannel for communication

Uses coaxial cable50 ohm Resistor know as

Terminator at the end of the cable

Kalau xde resistor, data keluar sebab RFI and EMI

menganggu electricity, terutama data dalam electricity.


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Bus Topology


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Ring Topology

In a ring topology, each node is connected to the twonearest nodes so that the entire network forms a circle

Data is transmitted clockwise, in one direction(unidirectional), around the ring

The fact that all workstations participate in delivery makesthe ring topology an active topology

A ring topology also differs in that it has no ends anddata stops at its destination and, twisted-pair or fiber-

optic cabling is used as the physical medium


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Ring Topology


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Star Topology

Every node on the network is connected through a centraldevice, such as hub , switch etc..

Uses twisted-pair or fiber-optic cabling


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Star Topology


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Hybrid

The hybrid topology uses the physical layout of a star inconjunction with the ring topologys data transmissionmethod

Data is sent around the star in a circular pattern

This hybrid topology benefits from the fault tolerance of thestar topology

In a hybrid topology, groups of workstations are star-connected to hubs and then networked via a single bus

With this design, you can cover longer distances andeasily interconnect or isolate different network segments


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Hybrid Topology


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Communication

Media and Transmission


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What is a signal ?

Data is communicated by means of a signal, and a signalis a change in voltage over time

Distortion of the signal is known as interferenceNetworks are generally not resilient to signal interference

NICs, hubs and other devices generate signals whichtravel along the network mediaThe signals are converted to data as they travel through

the OSI layersCable testers can be used to check signal quality and

strength


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Measuring Signals

Frequency

Am

plitud

e


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Analogue Signals vs Digital

signalsAnalogue Signals

Human Voice best

example

Ear recognises sounds

20KHz or less

AM Radio 535KHz to

1605KHz

FM Radio 88MHz to

108MHz

Digital signals

Represented by Square

Wave

All data represented by

binary values

SingleBinary Digit

Bit

Transmission ofcontiguous group of

bits is a bit stream

Not all decimal values

can be represented by

binary


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Amplitude Modulation vsFrequency Modulation

AM- samefrequency,differentamplitudes

FM- Differentfrequencies


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Digital Signals


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Analogue vs Digital (Advan)

AnalogueAdvantages

Best suited for

audio and videoConsume less

bandwidth

Available world

wide

Less susceptibleto noise

Digital AdvantagesBest for

computer data

Can be easilycompressed

Can beencrypted

Equipment ismore commonand lessexpensive

Can rovide


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Asynchronous Transmission

Uses start and stop bits to delineate pieces of data,usually characters when used with modems

Less efficient than synchronous (overhead of bits)

Best suited for short bursts, such as Internet use

Less resistant to disruption


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How transmissions flow over media

Simplex only in one direction

Half-Duplex Travels in either direction, but not bothdirections at the same time

Full-Duplex can travel in either direction simultaneously


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Baseband vs. BroadbandTransmission

In baseband transmission, digital signals are sent throughdirect current (DC) pulses applied to the wire

In broadband transmission, signals are modulated asradio frequency (RF) analog pulses that use different

frequency ranges


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Jaring, time.com, tm.net - ISP


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DataPackets

Usually data will broke down into packets before it travel toother medium.

Packets = segment of data. The packets is divided into 3 parts:

The header Specifies information needed to describe.

Packet addresses (Source IP & Destination IP) Size of the packet Protocol

The data portion Contains the application data or information that needs to be

delivered.

The trailer information Contains Cycle Redundancy Check (CRC) checksum value.

The result of a complex binary mathematical calculation on thedata use to check all the packets are succeeded reach to thereceiver or not.


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Network Performance

Bandwidth = Refers to the performance (speed) ofthe network.

Usually measured in Megabit per second (Mbps).

latency


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Network Essential