Biotechnology 2 year

1. COMPUTER FUNDAMENTAL
PART 3
BY:SURBHI SAROHA

2. SYLLABUS
 Networking
 Networking types(LAN,WAN,MAN)
 Network topologies
 Internet evolution and services(E-mail, FTP,Telnet, Usenet News ,WWW)

3. NETWORKING
 A computer network comprises two or more computers that are connected—
either by cables (wired) or WiFi (wireless)—with the purpose of transmitting,
exchanging, or sharing data and resources.
 You build a computer network using hardware (e.g., routers, switches, access
points, and cables) and software (e.g., operating systems or business
applications).
 An interconnection of multiple devices, also known as hosts, that are connected
using multiple paths for the purpose of sending/receiving data or media.
Computer networks can also include multiple devices/mediums which help in the
communication between two different devices; these are known as Network
devices and include things such as routers, switches, hubs, and bridges.

4. NETWORK DEVICES

5. COMPUTER NETWORKTYPES
 As networking needs evolved, so did the computer network types that serve those needs.
Here are the most common and widely used computer network types:
 LAN (local area network): A LAN connects computers over a relatively short distance,
allowing them to share data, files, and resources. For example, a LAN may connect all the
computers in an office building, school, or hospital.Typically, LANs are privately owned
and managed.
 WLAN (wireless local area network): AWLAN is just like a LAN but connections between
devices on the network are made wirelessly.
 WAN (wide area network): As the name implies, aWAN connects computers over a wide
area, such as from region to region or even continent to continent.The internet is the
largestWAN, connecting billions of computers worldwide.You will typically see collective
or distributed ownership models forWAN management.

6. CONT….
 MAN (metropolitan area network): MANs are typically larger than LANs but
smaller thanWANs. Cities and government entities typically own and manage
MANs.
 PAN (personal area network): A PAN serves one person. For example, if you have
an iPhone and a Mac, it’s very likely you’ve set up a PAN that shares and syncs
content—text messages, emails, photos, and more—across both devices.
 SAN (storage area network): A SAN is a specialized network that provides access
to block-level storage—shared network or cloud storage that, to the user, looks
and works like a storage drive that’s physically attached to a computer.

7. CONT….
 CAN (campus area network): A CAN is also known as a corporate area network. A
CAN is larger than a LAN but smaller than aWAN. CANs serve sites such as
colleges, universities, and business campuses.
 VPN (virtual private network): AVPN is a secure, point-to-point connection
between two network end points (see ‘Nodes’ below). AVPN establishes an
encrypted channel that keeps a user’s identity and access credentials, as well as
any data transferred, inaccessible to hackers.

8. NETWORKTOPOLOGIES
 The layout arrangement of the different devices in a network.
 Common examples include: Bus, Star, Mesh, Ring, and Daisy chain.

9. MESHTOPOLOGY:
 In a mesh topology, every device is connected to another device via a particular
channel.
 In MeshTopology, the protocols used are AHCP (Ad Hoc Configuration Protocols),
DHCP (Dynamic Host Configuration Protocol), etc.
 Advantages of this topology:
 Communication is very fast between the nodes.
 It is robust.
 The fault is diagnosed easily. Data is reliable because data is transferred among
the devices through dedicated channels or links.
 Provides security and privacy.

10. PROBLEMS WITHTHISTOPOLOGY:
 Installation and configuration are difficult.
 The cost of cables is high as bulk wiring is required, hence suitable for less number
of devices.
 The cost of maintenance is high.
StarTopology:
 In star topology, all the devices are connected to a single hub through a cable.
 This hub is the central node and all other nodes are connected to the central node.
 The hub can be passive in nature i.e., not an intelligent hub such as broadcasting
devices, at the same time the hub can be intelligent known as an active hub.

11. ADVANTAGES OFTHISTOPOLOGY:
 If N devices are connected to each other in a star topology, then the number of
cables required to connect them is N. So, it is easy to set up.
 Each device requires only 1 port i.e. to connect to the hub, therefore the total
number of ports required is N.
 It is Robust. If one link fails only that link will affect and not other than that.
 Easy to fault identification and fault isolation.
 Star topology is cost-effective as it uses inexpensive coaxial cable.

12. PROBLEMS WITHTHISTOPOLOGY:
 If the concentrator (hub) on which the whole topology relies fails, the whole
system will crash down.
 The cost of installation is high.
 Performance is based on the single concentrator i.e. hub.
BusTopology:
 Bus topology is a network type in which every computer and network device is
connected to a single cable. It is bi-directional.
 It is a multi-point connection and a non-robust topology because if the backbone
fails the topology crashes.

13. ADVANTAGES OFTHISTOPOLOGY:
 If N devices are connected to each other in a bus topology, then the number of
cables required to connect them is 1, known as backbone cable, and N drop lines
are required.
 Coaxial or twisted pair cables are mainly used in bus-based networks that support
up to 10 Mbps.
 The cost of the cable is less compared to other topologies, but it is used to build
small networks.
 Bus topology is familiar technology as installation and troubleshooting techniques
are well known.

14. PROBLEMS WITHTHISTOPOLOGY:
 A bus topology is quite simpler, but still, it requires a lot of cabling.
 If the common cable fails, then the whole system will crash down.
 If the network traffic is heavy, it increases collisions in the network.To avoid this,
various protocols are used in the MAC layer known as Pure Aloha, Slotted Aloha,
CSMA/CD, etc.
 Adding new devices to the network would slow down networks.
 Security is very low.

15. RINGTOPOLOGY:
 In this topology, it forms a ring connecting devices with exactly two neighboring
devices.
 A number of repeaters are used for Ring topology with a large number of nodes,
because if someone wants to send some data to the last node in the ring topology
with 100 nodes, then the data will have to pass through 99 nodes to reach the
100th node.
 Hence to prevent data loss repeaters are used in the network.

16. ADVANTAGES OFTHISTOPOLOGY:
 The data transmission is high-speed.
 The possibility of collision is minimum in this type of topology.
 Cheap to install and expand.
 It is less costly than a star topology.
 Problems with this topology:
 The failure of a single node in the network can cause the entire network to fail.
 Troubleshooting is difficult in this topology.
 The addition of stations in between or the removal of stations can disturb the whole
topology.
 Less secure.

17. TREETOPOLOGY :
 This topology is the variation of the Star topology.This topology has a hierarchical
flow of data.
 Advantages of this topology :
 It allows more devices to be attached to a single central hub thus it decreases the
distance that is traveled by the signal to come to the devices.
 It allows the network to get isolated and also prioritize from different computers.
 We can add new devices to the existing network.
 Error detection and error correction are very easy in a tree topology.

18. PROBLEMS WITHTHISTOPOLOGY :
 If the central hub gets fails the entire system fails.
 The cost is high because of the cabling.
 If new devices are added, it becomes difficult to reconfigure.
HybridTopology :
 This topological technology is the combination of all the various types of
topologies we have studied above.
 It is used when the nodes are free to take any form.
 It means these can be individuals such as Ring or Star topology or can be a
combination of various types of topologies seen above.

19. ADVANTAGES OFTHISTOPOLOGY :
 This topology is very flexible.
 The size of the network can be easily expanded by adding new devices.
Problems with this topology :
 It is challenging to design the architecture of the Hybrid Network.
 Hubs used in this topology are very expensive.
 The infrastructure cost is very high as a hybrid network requires a lot of cabling
and network devices.

20. INTERNET EVOLUTION AND SERVICES(E-MAIL,
FTP,TELNET, USENET NEWS ,WWW)
Evolution of the Internet
 Although the Internet was developed much earlier, it only became popular in
households in the 1990s.
 The emergence of the Internet can be tracked by how many businesses and
homes started changing the way they worked and started connecting their
laptops and other devices to the Internet.
 However, the concept of hypertext transfer protocol (HTTP) as we know it today,
was created only during this time.
 This meant that people could access the same web pages on their devices now
and share information.

21. CONT…..
 There has been a dramatic growth in the number of internet users since its
inception. As a result, the number of computer networks that are connected has
grown exponentially too.
 It started with only connecting less than ten computers initially.Today, 440
million computers can be connected directly, making life easier for people across
the globe.
 Sharing information and knowledge has become extremely easy for those that
have access to the Internet.
 The country with the highest number of internet users is China, with 1.4 billion
users, followed by India with 1.3 billion and the United States of America with a
little over 0.3 billion users

22. INTERNET SERVICES
 To access/exchange a large amount of data such as software, audio clips, video clips, text
files, other documents, etc., we need internet services.You must use an Internet service to
connect to the Internet. Data can be sent from Internet servers to your machine via
Internet service. Some of the commonly used internet services are :
 Communication Services
 Information Retrieval Services
 FileTransfer
 WorldWideWeb Services
 Web Services
 Directory Services
 Automatic Network Address Configuration

23. CONT….
 Network Management Services
 Time Services
 Usenet
 NewsGroup
 Ecommerce

24. SERVICES(E-MAIL, FTP,TELNET, USENET NEWS
,WWW)
 E-Mail: Used to send electronic mail via the internet. It is a paperless method for sending
text, images, documents, videos, etc from one person to another via the internet.
 User Network (USENET): It hosts newsgroups and message boards on certain topics, and
it is mostly run by volunteers.
 Telnet: It’s used to connect to a remote computer that’s connected to the internet.
 FTP (FileTransfer Protocol): To share, transfer, or send a file or logical data item across
several users and/or machines, both locally and remotely.
 World WideWeb: The internet is a vast network of interconnected computers. Using this
network, you can connect to the world wide web (abbreviated as ‘www’ or ‘web’) is a
collection of web pages.The web browser lets you access the web via the internet.

25. THANKYOU