Networking started way back in 1969 with the development of the first network called the ARPANET (advanced research project agency network)
In mid 80's the national science foundation created anew high capacity network called NSfnet which allowed only academic research on its network.
so many private companies built their own networks, which were later interconnected along with ARPANET and NSFnet to form internet.
Internet availavble for commercial purpose all over the world (1989)
History of Internet: -
1972 birth of the internet.
vint Cerf and bob kahn, both of whom were part of the care ARPANET group collaborated on what they called the inter-netting project.
they wanted to link different networks together so that host on one network coul communicate with a host o a second, different network.
They developed gateway to connect different network.
They developed TCP (transmission control protocol), which splits into TCP and IP called TCP/IP
1981 (CSNET): -
Another milestone in internet history was the creation of CSNET in 1981.
CSNET was a network sponsored by the national science foundation(NSF)
1983 (ARPANET Split): -
1. MILNET(military user)
2. ARPANET(non-military user)
NSFNET (1986): -
with the success of CSNET, the NSF, sponsored NSFNET
1991 ANSNET(ADVANCED NETWORK AND SERVICES NET)
What is Network: -
A network consists of two or more computers that are linked in order to share resources.
A
computer network is a telecommunications network which allows digital devices
(nodes) to exchange data between each other using either wired or wireless
connections to share resources(h/w or s/w) e.g. internet.
· Networks come in many sizes, shapes and forms.
· They are usually connected together to make larger networks, with
the internet being the most well-known example of a network of networks.
What is internet: -
The internet is a vast network that connect computers all over the world.
What is computer Network? full details.
A group computers which are connected to each other for the purpose of sharing their resources is called computer network
Characteristics of computer network: -
1. Resource sharing
1. Resource sharing
2. Communication speed
3. Backup
4. Scalability
5. Reliability
6. S/W & H/W sharing
7. Security
Network Devices: -
HUB, Switch, Bridge, Gateway, Modem, Router, Repeater etc......
Network Types: -
1. PAN(personal area network): -
.png "PAN(personal area network)")
Use: - Home(for personal use)
LAN(Local Area Network): -
Range: - (<150m)
Use: - (office building)
MAN(Metropolitan Area Network): -
Range: - (<50km)
Use: - Within city
WAN(Wide Area Network): -
Range: - (Not fixed)
Use: -(use for countries or all around world)
Advantages: -
1. Open to everyone
2. File sharing
3. Security
4. Easy to add new devices
5. Backup & Storage
Disadvantages: -
1. Network device required
2. Virus attack
3. Required Handler
4. High speed internet
5. Server
Data communication
Data communication are the exchange of data between to devices via
some transmission medium.
Data
communication system has five components
1. 1. Message- information
(data) to be communication e.g. text, audio, video.
2. 2. Sender- device how sends
the message (computer, phone, television etc.)
3. 3. Receiver- device how
receives the message (computer, phone, television etc.)
4. 4. Transmission medium- is
the physical path by which a message travels from sender to receiver.
5. 5. Protocol- the of rules
that governs the data communication.
Effectiveness
of the data communications system depends on four fundamental characteristics
1. 1. Delivery- Must deliver the
data to correct destination.
2. 2. Accuracy- Must be deliver
accurately without any error
3. 3. Time- Must deliver the
data in a timely manner, sometime time in real time applications data delivered
after time is useless.
4. 4. Jitter- Refers to
variation in the packet arrival time i.e. the uneven delay between the packets
(mismatch in audio and picture in a video)
What is HUB? full explanation: -
1. HUB is a network device that is used to connect multiple computers in a network.
1. HUB is a network device that is used to connect multiple computers in a network.
2. All the information send to the HUB is automatically send to each port to every device.
3. A HUB is less expensive, less intelligence & less complicated
4. HUB generally used to connect computers in a LAN
5. Transmission mode of HUB is Half duplex.
1. The HUB can broadcast the message
2. it is less expensive that anyone can use it.
3. Easy to installation.
4. Robust
Disadvantage: -
1. if the HUB is failed the entire network will be failed.
2. we can't send private/personal data through hub.
3. HUB doesn't provide any security
4. HUB can't support full duplex transmission mode.
What is switch? full explanation.
Switch is a network device that connects multiple computers together in the network.
it is mainly used to send the private message as well as their is no wasting of data.
Switch can easily identified that which device is connected with port by using MAC address, that why it delivered message on particular destination machine.
Note: - Switch is more intelligent than HUB
Advantage: -
1. it generally used to uni-cast the message.
2. it provides more security than HUB.
3. switch support full duplex data transmission mode.
4. it is used to send the data packet based on mac address.
5. if a node fails, there will be no effect in the entire network.
disadvantage: -
1. if switch is failed then entire network will be failed.
2. it is more expansive
3. difficult to setup
what is router? Full explanation.
Router is a network device which works as a traffic controller. A main work of router is to choose a congestion free path thorough which the data packet will travel.
Router receive data packets to the sender, analyze and forward those data packets then giving to receiver.
Note: - Router uses both LAN & WAN network.
Advantage: -
1. it provides connection b/w two dis-similar type of network.
2. Transmission rate is very high
3. it internally uses some algorithm to find-out congestion free path
4. it provides both wire or wireless facility.
Disadvantage: -
1. Router is more expansive compare to other network device.
2. Router are complex to maintain.
3. Security issues
4. it only work with routable protocol.
What is Repeater? full explanation.
Repeater is a network device through which we can boostup the weak signals when the signal travels in the network after travelling some distance the intensity of the signal becomes low.
in order to regenerate the weak signal we should use repeater device.
Note: - it is used in wired & wireless.
Advantage: -
1. it is used to regenerate the weak signal
2. repeaters than other network device
3. repeaters has the ability to extend the length of signal
4. increase/maintain the signal performance
Disadvantage: -
1.it required no of repeater after some distance.
2. Repeaters also unable to connect dis-similar type of network
3. they can't reduce network traffic
What is bridge? full explanation.
Bridge is a network device that is used to repeater LAN into no of section.
Note: - it operates both physical as well as data link layer of OSI model
Advantage: -
1. by using bridge device we can extends network.
2. it broadcast the data to each node like HUB & repeater.
3. collision can be reduced easily.
4. it is more intelligent.
Disadvantage: -
1. it doesn't establish connection between two different network.
2. once it broad cast the messages then it is incapable to stop the messages.
3. it is more expensive.
4. the transmission rate of data is slowly than repeater.
What is Gateway? full explanation.
Gateway is a hardware device that is used to connect two dissimilar type of network.
it allow us to send & receive data through the internet even it is LAN network.
Note: - it operates all 7 layer of OSI model
Advantage: -
1. It connects two network which has different protocol.
2. it operate all 7 layer of protocol
3. we can't access the internet without gateway
4. it provide some security
Disadvantage: -
1. it is more expensive
2. data transmission rate is slower
3. difficult to maintain as well as very complex.
4. it is less intelligent
What is NIC? full explanation.
NIC stands for network interface card. it is hardware device without which we can't connect computer to the network/internet.
Type: -
1. internal network card.
2. eternal network card.
Internal network card
in this cards the motherboard has a slot for the n/w card where it can be inserted. it requires a network cable(RJ-45) to provide n/w access.
External network card
In desktop & laptop that don't have an internal NIC, external NIC's are used.
Type: -
1. wireless
2. USB cable
Modem
modem stands for modulator & demodulator, it is a network device that is placed between the computer system and telephone line.
it has two part modulator & demodulator.
Modulator convert digital as demodulator convert analog to digital signal.
What is topology? full explanation.
The physical arrangement of the computer system/node. which is connected to each other via communication medium is called topology.
Type of Topology
1. Bus topology
2. Ring topology
3. Star topology
4. Mesh topology
5. Hybrid topology
6. Tree topology
Bus topology
In bus topology, one long cable acts as a single communication channel & all the devices are connected to this cables.
Advantage: -
1. easy to add/ remove nodes in a network.
2. required only cable.
3. it is less expensive.
4. it broadcast the messages to device which are connected through cable.
5. it is easy to maintain.
6. in case of any computer failure, there will be no effect on other devices.
working in progress...............
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