Bandwidth

Bandwidth

• Data in digital computer system is represented in the form of bit ( binary digit).
• The amount of data ( amount of bits) that can be transmitted through a communication channel) during specific period of time is Bandwidth.
• The bandwidth in digital system is measured using the units bps (bits per second).
• Similarly, larger units are: 

                    Kbps: kilobits per second

                    Mbps: Megabits per second

• The bandwidth in analog system are measured using the unit hertz.

                      KHz: Kilo Hertz

                      MHz: Mega Hertz

                      GHz: Giga Hertz

• Some notes: 

Cable internet service (750MHz to 1000 MHz or 1 GHz)

Similarly, DSL and Satellite have high bandwidth connection

Note: Mb/s stands for Megabits per second

Whereas mb/s stands for millions of bits per second

Limited broadcasting and Direct broadcasting

Limited Broadcasting

This type of broadcasting allows you to send stream of packets to devices on the network cluster on which you residue.

Direct Broadcasting

This type of broadcasting allows you to send stream of packets to devices over the other network.

For more information about other types of casting, click below.

Different types of casting with examples and explanation

Differences between simplex and duplex mode of data transmission

Differences between Simplex and Duplex mode of data communication

S.N.	Simplex mode	Duplex Mode
1	It provides only one way communication.	It provides two way communication.
2	We cannot get feedback from the receiver in this mode of communication.	Receiver can get feedback about whether successful transmission has happened or not in duplex mode of communication.
3	It is cheaper in comparison.	It is costlier as it needs two separate channels for sending and receiving data.
4	It is comparatively slower as receiver has to wait for sender to finish the transfer of data as data transmission can only happen alternately.	It is faster as data transmission is simultaneous

For more information on simplex and duplex mode of communication click below:

Modes of data communication with explanation and examples

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Casting and it's types:- Unicast, Multicast and Broadcast

Casting

Casting is a variety of function that transmit or convert data.

These are three types of casting as given below:-

1. Unicast
2. Multicast
3. Broadcast

Unicast

Unicast is the term used to describe communication where a piece of information is sent from one point to another point where there is just one sender and one receiver . A unicast transmission is always meant for one receiving address. 

Some examples are:-

1. Radio and TV communication
2. Browsing a Website ( Webserver is the sender and your computer is the receiver)
3. Downloading a file from a FTP server ( FTP server is the sender and your computer is the receiver. )

Multicast Transmission

Multicast Transmission is both "one to many" and "many to many" technique which sends information from a single source to as many destinations as one expresses a specific interest in receiving it. 

Multicasting is the networking technique of delivering the same packet simulataneouly to a group of clients. 

It is useful if a group of clients require a common set of data at the same time. 

The majority of installed LANs (e.g.. ethernet), shared LANs (using hubs/repeaters),etc. support multicast transmission mode.

Example of multicast transmission mode are 

Multicast Windows Deployment Services (WDS)

OS Deployment traffic

UP TV, etc.

Broadcast Transmission

Broadcast transmission is the term used to describe communication where a piece of information is sent from one point to all other points. 

In this case, there is just one sender, but the information is sent to all connected receivers. 

Broadcast Transmission simultaneously transmits the same information to all nodes on a network. 

In Broadcast, there is only one sender and the data is sent only once. 

But the broadcast dat is delivered to all connected devices.

Broadcast communication is supported on most LANs (e.g.. Ethernet) and may be used to send the same message to all computers on the LAN.)

Television signals sent from a public network to viewers across the country or globe are the simple examples of broadcast transmission. 

Other examples:

ARP request message

DHCP DISCOVER Message

Broadcasting are also of two types:

1. Limited broadcasting 2. Direct broadcasting

Please click on the items to know about them.

Data transmission modes

Data transmission Modes

The way in which the data are transmitted from one location to another is called data transmission mode.

Simplex Mode

This mode allows data to transfer in only one way in only one direction. 

1. In simplex mode, data are transmitted in only one direction on the data communication medium.

2. A terminal can either send data and cannot receive it or it can only receive data but cannot send it

3. It is the cheapest communucation medium.

4. Transmission of data is not confirmed.

5. For e.g.. television, radio broadcasts, etc.

Half Duplex Mode

• In this mode, data can be transmitted in both directions but only in one direction at a time.
• During transmission of Data, one of the terminals is the transmitter and the other is receiver.
• Direction of data communication is reversed each time for sending and receiving data
• Transmission of the data can be confirmed.
• For e.g.. email, fax

Full Duplex Mode

• Data can be transmitted in both directions simultaneously at the same time
• It is the fastest mode of transmitting data as no time gets wasted in switching direction.
• Transmission of the data can be confirmed.
• E.g.. landline, mobile phones & computer

Similarly some other modes of data transmission are:-

TDD (Time Division Duplex)

FDMA ( Frequency Digital Multiple Access)

TDMA

CDMA

Higher level money exchange questions

Questions

1. It is given that £1 is equal to Rs. 155.63. If 2% commission should be paid to exchange Rs  500000 into Pound sterling, how much pound sterling can he receive? Find it.

Solution:

Let the exchange amount be X.

Commission amount =

= 2% of X

= 2/100 ×X

= X/50

By question, 

X/50 +X =500000

Or, 51X=500000×50

Or, X=490196.07 £

Amount of pound sterling received= 

=490196.07/155.53

=3149.75 £

Money exchange practice questions with answers

1. Using the rate of Rs. 110 per US dollar, calculate the US Dollars for RS. 11000.

Solution:

Given:

1$=Rs. 110

Rs 11000=X$

Using chain rule,

Or, 1×11000=110×X

Or, 11000/110=X

Or, X=100$

.•. Rs. 11000=100$

2. If 1000 yen=Rs.984 then convert 550000 yen into Rupees.

Solution:

Given:

Rs. 984=1000yen

550000=Rs. X

Using chain rule,

Or, 984×550000=1000×X

Or, 984×(550000/1000)=X

Or, 984×550=X

.•. X= Rs. 5,41,200

3. If 1 Swiss Franc=Rs 108.33 then find the Swiss franc for Rs. 32499.

Solution:

Given:

1 Swiss franc =Rs.108.33

Rs. 32499= X Swiss Franc

Using chain rule,

1 Swiss franc × Rs 32499=Rs. 108.33 × X Swiss Franc

Or, 32499/108.33= X

Or, X=300 Swiss Franc

Now there are some practice questions for you.

Answer key: