Author Archives: Tech Tonic

After a long time, I woke up early in the morning. And the most amazing thing I realised is that we all should wake up early in the morning because the beauty of our earth is much more prettier in the morning.

The beauty is in the rising Sun, the voice of birds chirping, cleanliness all around and the fresh air.

The worlds best music is in the environment we hear in the morning.

I would like to suggest you to atleast try to wake up early thn you’ll be addicted to it.

Our famous and one of the favourite bollywood star AKSHAY KUMAR always wakes early in the morning and completes most of his work. It gives you a different energy which could keep you fresh and energetic for the whole day.

Hey..!!

As everyone is aware of what recently happened. We lost one of the biggest and talented star of our bollywood and we are aware of the reason i.e suicide.

I want to ask..how many people in this world think that suicide is the most easiest solution we have for all problems..??

But every year we loose 500-1500 people due to suicide. Mostly this occurs in students during their studies phase. I want to ask them “Is their life is so cheap than a piece of paper (marksheet). No man, I would rather ask them to have guts to say it to your parents that you can’t handle such kind of stress and do something in which you have keen interest. I’m sure your life is more important to your parents as well and they will accept the things in which you are interested my dear.

Plz guyz…Do share the things you are suffering inside your head. Definitely it will release some pressure and give you some relief.

Because you might not be aware of the pain that your parents will suffer after you. You are the only hope for them to live , they also wish to grow old with you and you are spoling your dreams as well as your parents.

So, before doing anything think twice and the best option is to share it with your parents because I personally do that and I feel so relieved.

Last but not the least I show condolences to the family of Sushant Singh Rajput.

R.I.P

In data communication terminology, a transmission medium is a physical path between the transmitter and the receiver i.e it is the channel through which data is sent from one place to another. Transmission Media is broadly classified into the following types:

1. Guided Media:
It is also referred to as Wired or Bounded transmission media. Signals being transmitted are directed and confined in a narrow pathway by using physical links.
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Features:

• High Speed
• Secure
• Used for comparatively shorter distances

There are 3 major types of Guided Media:

(i) Twisted Pair Cable –
It consists of 2 separately insulated conductor wires wound about each other. Generally, several such pairs are bundled together in a protective sheath. They are the most widely used Transmission Media. Twisted Pair is of two types:

1. Unshielded Twisted Pair (UTP):
   This type of cable has the ability to block interference and does not depend on a physical shield for this purpose. It is used for telephonic applications.Advantages:
   • Least expensive
   • Easy to install
   • High speed capacity
   Disadvantages:
   • Susceptible to external interference
   • Lower capacity and performance in comparison to STP
   • Short distance transmission due to attenuation
2. Shielded Twisted Pair (STP):
   This type of cable consists of a special jacket to block external interference. It is used in fast-data-rate Ethernet and in voice and data channels of telephone lines.Advantages:
   • Better performance at a higher data rate in comparison to UTP
   • Eliminates crosstalk
   • Comparitively faster
   Disadvantages:
   • Comparitively difficult to install and manufacture
   • More expensive
   • Bulky

(ii) Coaxial Cable –
It has an outer plastic covering containing 2 parallel conductors each having a separate insulated protection cover. Coaxial cable transmits information in two modes: Baseband mode(dedicated cable bandwidth) and Broadband mode(cable bandwidth is split into separate ranges). Cable TVs and analog television networks widely use Coaxial cables.
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Advantages:

• High Bandwidth
• Better noise Immunity
• Easy to install and expand
• Inexpensive

Disadvantages:

• Single cable failure can disrupt the entire network

(iii) Optical Fibre Cable –
It uses the concept of reflection of light through a core made up of glass or plastic. The core is surrounded by a less dense glass or plastic covering called the cladding. It is used for transmission of large volumes of data.

Advantages:

• Increased capacity and bandwidth
• Light weight
• Less signal attenuation
• Immunity to electromagnetic interference
• Resistance to corrosive materials

Disadvantages:

• Difficult to install and maintain
• High cost
• Fragile
• unidirectional, ie, will need another fibre, if we need bidirectional communication

2. Unguided Media:
It is also referred to as Wireless or Unbounded transmission media.No physical medium is required for the transmission of electromagnetic signals.

Features:

• Signal is broadcasted through air
• Less Secure
• Used for larger distances

There are 3 major types of Unguided Media:

(i) Radiowaves
These are easy to generate and can penetrate through buildings. The sending and receiving antennas need not be aligned. Frequency Range:3KHz – 1GHz. AM and FM radios and cordless phones use Radiowaves for transmission.

Further Categorized as (i) Terrestrial and (ii) Satellite.

(ii) Microwaves
It is a line of sight transmission i.e. the sending and receiving antennas need to be properly aligned with each other. The distance covered by the signal is directly proportional to the height of the antenna. Frequency Range:1GHz – 300GHz. These are majorly used for mobile phone communication and television distribution.

(iii) Infrared
Infrared waves are used for very short distance communication. They cannot penetrate through obstacles. This prevents interference between systems. Frequency Range:300GHz – 400THz. It is used in TV remotes, wireless mouse, keyboard, printer, etc.

ISDN is a circuit-switched telephone network system, which also provides access to packet switched networks, designed to allow digital transmission of voice and data over ordinary telephone copper wires, resulting in potentially better voice quality than an analog phone can provide.

ISDN Interfaces:
The following are the interfaces of ISDN:

1. Basic Rate Interface (BRI) –
There are two data-bearing channels (‘B’ channels) and one signaling channel (‘D’ channel) in BRI to initiate connections. The B channels operate at a maximum of 64 Kbps while the D channel operates at a maximum of 16 Kbps. The two channels are independent of each other. For example, one channel is used as a TCP/IP connection to a location while the other channel is used to send a fax to a remote location. In iSeries ISDN supports basic rate interface (BRl).The basic rate interface (BRl) specifies a digital pipe consisting two B channels of 64 Kbps each and one D channel of 16 Kbps. This equals a speed of 144 Kbps. In addition, the BRl service itself requires an operating overhead of 48 Kbps. Therefore a digital pipe of 192 Kbps is required.

2. Primary Rate Interface (PRI) –
Primary Rate Interface service consists of a D channel and either 23 or 30 B channels depending on the country you are in. PRI is not supported on the iSeries. A digital pipe with 23 B channels and one 64 Kbps D channel is present in the usual Primary Rate Interface (PRI). Twenty-three B channels of 64 Kbps each and one D channel of 64 Kbps equals 1.536 Mbps. The PRI service uses 8 Kbps of overhead also. Therefore PRI requires a digital pipe of 1.544 Mbps.

3. Broadband-ISDN (B-ISDN) –
Narrowband ISDN has been designed to operate over the current communications infrastructure, which is heavily dependent on the copper cable however B-ISDN relies mainly on the evolution of fiber optics. According to CCITT B-ISDN is best described as ‘a service requiring transmission channels capable of supporting rates greater than the primary rate.

Principle of ISDN:
The ISDN works based on the standards defined by ITU-T (formerly CCITT). The Telecommunication Standardization Sector (ITU-T) coordinates standards for telecommunications on behalf of the International Telecommunication Union (ITU) and is based in Geneva, Switzerland. The various principles of ISDN as per ITU-T recommendation are:

• To support switched and non switched application.
• To support voice and non voice application.
• Intelligence in the network.
• Layered protocol architecture.
• Variety of configurations.

In large networks, there can be multiple paths from sender to receiver. The switching technique will decide the best route for data transmission.

Switching technique is used to connect the systems for making one-to-one communication

There are basically three types of switching methods. Out of three methods, circuit switching and packet switching are commonly used but the message switching has been opposed out in the general communication procedure but is still used in the networking application.

1. Circuit Switching

Circuit switching is a connection-oriented network switching technique. Here, a dedicated route is established between the source and the destination and the entire message is transferred through it.

It is of two types:

I. Space Division switch

A space division circuit switch is one in which all bits arriving on an input port are switched to a given output port. Crossbar switch. N inputs and N outputs; can connect any input to any output. Non-blocking: if the output line that you are trying to reach is free, the switch itself should not block the call.

II. Time Division switch

 An all-electronic switching system based on time division multiplexing (TDM) principles: an input digitized signal from a source is connected to an output trunk by assigning a group of bits from the input data stream to a time slot in a high-speed TDM output data stream

Advantages

• It is suitable for long continuous transmission, since a continuous transmission route is established, that remains throughout the conversation.
• The dedicated path ensures a steady data rate of communication.
• No intermediate delays are found once the circuit is established. So, they are suitable for real time communication of both voice and data transmission.

Disadvantages

• Circuit switching establishes a dedicated connection between the end parties. This dedicated connection cannot be used for transmitting any other data, even if the data load is very low.
• Bandwidth requirement is high even in cases of low data volume.
• There is underutilization of system resources. Once resources are allocated to a particular connection, they cannot be used for other connections.
• Time required to establish connection may be high.

2. Message Switching

Message switching is a connectionless network switching technique where the entire message is routed from the source node to the destination node, one hop at a time. It was a precursor of packet switching.

Advantages

1. As message switching is able to store the message for which communication channel is not available, it helps in reducing the traffic congestion in network.
2. In message switching, the data channels are shared by the network devices.
3. It makes the traffic management efficient by assigning priorities to the messages.

Disadvantages

1. Message switching cannot be used for real time applications as storing of messages causes delay.
2. In message switching, message has to be stored for which every intermediate devices in the network requires a large storing capacity.

3. Packet Switching

Packet switching is a method of grouping data that is transmitted over a digital network into packets. Packets are made of a header and a payload. Data in the header is used by networking hardware to direct the packet to its destination where the payload is extracted and used by application software.

It is of two types:

I. Datagram Approach

Datagram packet-switching is a packet switching technology by which each packet, now called a datagram, is treated as a separate entity. Each packet is routed independently through the network. … The individual packets which form a data stream may follow different paths between the source and the destination.

II. Virtual Circuit Approach

A virtual circuit is a means of transporting data over a packet-switched network in such a way that it appears as though there is a dedicated physical link between the source and destination end systems of this data. The term virtual circuit is synonymous with virtual connection. 

Advantages

• Delay in delivery of packets is less, since packets are sent as soon as they are available.
• Switching devices don’t require massive storage, since they don’t have to store the entire messages before forwarding them to the next node.
• Data delivery can continue even if some parts of the network faces link failure. Packets can be routed via other paths.
• It allows simultaneous usage of the same channel by multiple users.
• It ensures better bandwidth usage as a number of packets from multiple sources can be transferred via the same link.

Disadvantages

• They are unsuitable for applications that cannot afford delays in communication like high quality voice calls.
• Packet switching high installation costs.
• They require complex protocols for delivery.
• Network problems may introduce errors in packets, delay in delivery of packets or loss of packets. If not properly handled, this may lead to loss of critical information.

Backbone Network is a network containing high capacity connecting infrastructure backbone to different part of network.

Backbone network allows multiple LAN to get connected.

There are three categories of backbone network:-

1. Bus Backbone

Bus backbones are normally used as a distribution backbone to connect different buildings in an organization. Each building can comprise either a single LAN or another backbone (normally a star backbone). A good example of a bus backbone is one that connects single- or multiple-floor buildings on a campus.

2. Star Backbone

In a star backbone, sometimes called a collapsed or switched backbone, the topology of the backbone is a star. In this configuration, the backbone is just one switch that connects the LANs. … In a multi floor building, we usually find one LAN that serves each particular floor. A star backbone connects these LANs.

3. Remote LAN Backbone

In this type of backbone network the connection are done through the bridge called remote bridges which acts as connecting devices in connect LANs as point to point network link.

Example of point to point networks are leased telephone lines or ADLS lines. Such a point to point network can be considered as being equivalent ta a LAN without stations.

It is the layered framework for the design of the network system that allows communication between all types of computer network.

It has seven separate layers and each layer call upon the services of the layer just below it.

Layer 1 : Application layer

Layer 2 : Presentation layer

Layer 3 : Session layer

Layer 4 : Transport layer

Layer 5 : Network layer

Layer 6 : Datalink layer

Layer 7 : Physical layer

1. Physical layer – It is responsible for moving individual bit from one to next.

Functions

• It defines the type of transmission media.
• It defines the type of encoding to be used.
• It defines the duration of bit or the data rate. ( No. of bits send per second)
• Synchronisation of bits.
• Line configuration (point to point and multipoint)
• Topology
• Transmission mode ( simpler, half duplex, full duplex)

2. Datalink layer– It transforms physical link layer into reliable link.

Functions

• Framing i.e. conversion of bits to frame.
• Physical addressing i.e. describes header and footer.
• Access control used foe security purpose.
• Flow control i.e. the rate at which data should be send.
• Error control i.e. can be changed any bits.

3. Network layer– Responsible for source to duration delivery of packet.

Functions

• Header to packet coming from upper i.e. logical addressing.
• Which route needs to be choosed i.e. routing.

4. Transport layer– Responsible for process to process delivery.

Functions

• Service point addressing
• Segmentation and resemble
• Connection control i.e. connectionless and connection oriented.
• Flow and error control

5. Session layer– It is responsible for two functions that are dialogue control and synchronisation.

Functions

• Dialogue control- provides permission to control two systems and it could be either in half duplex and full duplex mode.
• Synchronisation is to add certain check points.

6. Presentation layer- It deals with the syntax and semantics of the information exchanged between two systems.

Functions

• Converting a message into compatible bit stream i.e. translation.
• Plain text into cioher text i.e. encryption.
• Reducing no. of bits contained in the information i.e. compression.

7. Application layer- It enables the user to access the network.

Functions

• Network virtual terminal i.e. software version of physical terminal.
• Email services and directory services.
• File transfer access and management.

It is an electronic device which receives signals and transmit it.

Repeaters are used to extend the transmission so that the signal can cover long distances or be received on the other side of destruction.

Ex – If we want to send an information from device 1 to device 3, repeater is required.

How it works?

The information which needs to be send first go to device 2 but this device doesn’t keep that information but further with the help of repeater it forwards the information.

Network topology is schematic description of network arrangements, connecting various nodes (sender and receiver) through connecting lines.

There are following types of topologies:-

1. Star topology

2. Ring topology

3. Bus topology

4. Mesh topology

5. Tree topology

6. Hybrid topology

Further we will learn about them in detail:-

1. Mesh Topology

In mesh topology, every device is point to point connected to every other devices.

It creates a kind of mesh between each other.

Ex- In class every student is aware of his classmates and somehow connected to them to make it as a whole class. Similarly, in this also every device is interconnected to each other.

Advantages

1. Robust

2. Easily fault detection

3. Security

Disadvantages

1. Installation and configuration

2. Cost of maintenance

3. Cost of I/O port

2. Star Topology

In star topology, each nodes has a dedicated point to point link to a Central controller i.e HUB.

The devices are not directly linked to each other.

To communication between two  devices are done with the help of hub.

Star topology is much better than mesh topology because mesh topology is so complex whereas star topology is less complex.

Advantages

1. Robust

2. One link and one I/P port required

3. Easy installation and configuration

Disadvantages

1. Cost of installation and configuration is high

2. If hub fails, the whole system crashes

3. Bus topology

Bus topology is a multipoint structure.

One long cable act as a backbone to connect all nodes in the network.

The structure is constructed btw two points i.e start point and end point.

Advantages

1. Less cost of installation and configuration

2. One cable and n dropline are required

3. Cost is less then other topology

Disadvantages

1. If long cable is damaged then all the nodes connected to it will also stop working.

2. Collision of data is possible.

4. Ring Topology

By name it is clear that what is ring topology, In ring topology, the devices has dedicated point to point connection but only with two devices at a time.

There will be n no. of devices and n repeaters.

Advantages

1. Easy installation and configuration

2. Collision is minimum

Disadvantages

1. Addition or deletion of node disturbs whole topology.

2. Detection of trouble becomes difficult.

5. Tree Topology

The structure of tree topology is the same as we have learned it in data structure.

In tree topology, there exists one root node n the rest nodes are connected to it in the tree format.

It must be of atleast 3 level otherwise it won’t be considered as tree topology.

Advantages

1. Error detection is easy.

2. Nodes can be easily extended.

Disadvantages

1. Large amount of cable used.

2. Costly

6. Hybrid Topology

Hybrid topology is a collection of two or more topologies i.e. star, bus and ring topologies.

The diagram of hybrid topology can created by joining the hubs of star, ring and bus topologies.

Advantages

1. Scalable coz size can be easily extended.

2. Flexible

Disadvantages

1. Design is complex

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