Computer Networks, Part-1:
"Everything You Need To Know About Networks".
Hey there! I'm Vishwa, a DevOps Engineer. Curious about me? Check out my profile and posts, but here's a quick overview. I've spent the past two years building credibility, consistently working on projects, and upskilling myself. I'm a self-learner, and my posts reflect my journey. When it comes to technical expertise, I'm proficient in Linux, Networking, Shell Scripting, Docker, Ansible, Terraform, Kubernetes, Prometheus, Grafana, Loki, Jenkins, GitHub Actions, Python, Go, and Java. Wondering about my cloud experience? I'm well-versed in AWS, Digital Ocean, and GCP. I'm also skilled in troubleshooting. My ability to self-motivate and search for solutions allows me to quickly adapt to new technologies. And yes, I love writing. Sharing knowledge through blogs is something I’m passionate about. To reach out to Me, You can do DM and also leave an E-mail here at vishwa20042003@gmail.com, Waiting for your Connections and Opportunities.
Author:
Hey, folks am Vishwa currently pursuing 3rd year of BTech Information Technology and am learning DevOps with the help of Communities and Opensource.
Am doing LearningInPublic & BuildingInPublic so I'll be sharing my learnings on my Socials and I'll make content also by Blogging my learnings this is my first blog ever.
Let's head into the content.
Basic's:
What are Computer Networks?
Computer Networks are nothing but many computers that connected is called Computer Networks.
What is the Internet?
It is nothing but the Collection of Computer networks known as the Internet.
Define Protocol.
The protocol is like a set of rules that are being used for sharing different types of Data between computers. Example: TCP, UDP.
Define WWW.
WWW stands for World Wide Web, it is nothing but a collection of text, pages and hyperlinks etc. It is identified by URL(Uniform Resource Locations).
Example: https://example.com/
A small history of Computer Networks, The first Network connection was built in the US for communication ARPA net and the connection was between MIT, STANFORD, VCLA, and UTAH (These four are Research focused).
Why do we need Protocols?
Let's say one country has an application that communicates with different rules and another country may go with different rules to avoid this kind of thing we need protocols and the Internet Society is responsible for these things.
Client-Server Architecture:
Through our computer's browser(Client) we Request something that we want and on the other side, they have a separate Server for Response they will send back a bunch of things with a webpage as a response.
Note: Our Computer can work as Server as well as a Client.
Protocols:
TCP:
TCP stands for Transmission Control Protocol and it ensures that the data will be reached the destination without being lost or corrupted on the way. Example: Email.
UDP:
UDP stands for User Datagram Protocol and it is quite opposite to TCP in that data may be lost on the way and the receiver may be fine with this. Example: Video Conferences.
HTTP:
HTTP stands for Hyper Text Transfer Protocol and this is being used by WWW, it defines the format of data transfers between Web-Servers and Web-Client.
How Data is Transferred?
The sender doesn't transfer data in one single go, it sends it as packets. The packet is nothing but a collection of a small amount of data.
IP Address:
IP stands for Internet Protocol. The Computers and Servers are identified by IP address only. Format: X.X.X.X (Every single X has some number between 0 to 255).
To check your own computer's IP use the curl command, $curl ifconfig. me -s.
ISP (Internet Service Provider) will have a Global IP address and the Network Device like Modem/Router will assign IPs to their connected device with the help of DHCP (Dynamic Host Configuration Protocol) and the NAT (Network Access Transfer) will identify which device to send the data.
Note: Global IP address is nothing but if we request Google and their server will know this request is made from this IP(our ISP), not our Computer's IP.
- Now which application is requested from our device that will be identified with the help of the Port Number? (IP identifies Device & Port Number identifies which application is on the device).
Port Number:
It is used to identify the application which is requested from the device.
A 16-bit number each contains 0's and 1's.
There are 65536 ports in that 0-1023 are reserved, 1024 -49152 are registered for applications like MySQL, and MongoDB and we can use the rest for our use. Note: Port Number 80 is used to identify the application which is requested.
How is the Computer connected?
In Guided and Unguided ways (Basically Wired & Wireless respectively).
Wired uses Twisted Pair Cable, Coaxial Cable and Fibre Optical whereas Wireless is Radiowave and Microwaves.
Wired are faster than Satellites and Wireless are used for a lower range like Bluetooth, Wifi etc.
Types of Networks:
LAN - Local Area Network (used in houses/offices like Wifi and Ethernet), MAN - Metropolitan Area Network (across Cities), WAN - Wide Area Network (across Countries by FibreOptical Cables).
Topologies:
Bus:
Computers are connected to a particular cable and If the cable breaks no data Transfers.
Only one system can send data at one time.
Ring:
Every computer is connected, connected like a ring.
It has limitations if cable breaks, it spoils the entire network and unnecessary calls are also made let's say we have A, B, C, D and E as a ring network, for A-D (data transfers), it calls B & C also because there is no direct connection.
Star:
One central(Hub) is there, all are connected to that central hub.
If the central fails, the network goes down.
Tree:
- It is nothing but the Combination of Bus and Star.
Mesh:
Every single computer is connected to every other computer.
It is expensive because so much of wires are needed.
Scalability Issues that is if one now wants to add to the network, that has to be connected with every single computer.
Structure of the Network:
The Network's structure is based on the OSI Model.
OSI Model stands for Open System Interconnection Model and this is how the Internet works.
This is the standard way for 2 or more computers to communicate with each other.
It has Seven Layers and they are
1. Application layer,
2. Presentation layer,
3. Session layer,
4. The transport layer,
5. Network layer,
6. Datalink layer,
7. Physical layer.
1. Application layer:
This is the topmost layer of the OSI model & basically, it is implemented in
software/apps which are used for user interaction.
2. Presentation layer:
- This layer is used to collect the data from the application layer and converts it
into a machine-readable format.
- It encrypts the data and also compresses it to reduce traffic.
3. Session layer:
- It helps to manage the connections between the sender and the receiver.
- It enables the sending and receiving of data followed by the termination of
established sessions.
- Before a session establishes authentication takes place
4. Transport layer:
- In this layer, transportation takes place in three ways they are
Segmentation, Flow control, and Error control.
-> Segmentation: It is nothing but dividing the data into smaller ones, each &
every divided segment contains Source & Destination port number with the
sequence number to reassemble the data segments.
-> Flow control: It controls the flow of data that is being transferred.
Example: Sending at 40Mbs and receiving at 20Mbs means it slows down the
process.
-> Error control: It is nothing but some corrupted data, it adds a checksum to
know whether the data received are correct or not.
5. Network layer:
- It uses Routers because the data segments received will be transmitted from
one computer to another one in a different network.
- It assigns IP to every data packet that is received and It is called Logical
addressing.
- Load balance also happens here.
6. Datalink layer:
- A packet consists of three things IP of both the Sender & Receiver and the
Subnet mask(Masks the network part of the IP and leaves the host part to use).
- Physical addressing is done at this layer(
- MAC(physical) address is a 12-digit alphanumeric number of a network interface for our computer and the computer not only has only one MAC address, but
Bluetooth may also have one address and Wifi may have a different address.
- Adding IPs to the frame(units of data) & transmitting is the data link layer.
7. Physical layer
- It receives the data in bits and converts it into whatever signal it wants like
electrical, radio or light.
TCP/IP Model:
It contains only five layers only and the application layer, transport layer, network layer, datalink layer, and physical layer.
Network Devices:
1. Repeater:
- At the physical layer, it regenerates the received signal before it becomes weak or corrupted.
- It does not amplify, it only copies the signal bit by bit and
regenerates it.
- It is called a two-port device(two pairs of terminals that connect to an external
circuit).
2. Hub:
- It is a Multiport device and it connects multiple wires from different branches.
- Does not find the best path for data packets, leading to inefficiencies and
wastage.
3. Bridge:
- It operates at the data link layer and it is a repeater, also used to filter content
by reading the Mac addresses of the source and destination.
- Used for interconnecting two LANs working at the same protocol, it has a
single input and single output ports that make it a two-port device.
4. Switch:
- It is a Multiport bridge that boosts its efficiency and performance.
- Also, it is a datalink layer & performs error checking before forwarding the data
packets which improves efficiency.
5. Router:
- It is nothing but a route of the data packets to the destination address in the
network layer.
6. Gateway:
- It is a passage to connect two networks that may work on a different network
model.
- More complex than a router and switch.
- Works as a messenger agent takes data from one system and transfers it to
another. It is called protocol converters that work at any network layer.
7. Brouter:
- Combination of Bridge and Router. Works either at the data link layer or at the
network layer.
- While works as a router, capable of routing packets across networks and as a
bridge able to filter traffic at networks.
Continues at part-2.....
That's all in the part-1 folks, I'll be releasing part-2 of Computer Networks soon.
In Part-2 we will see about Web-Protocols, How an Email works? and about DNS, then a little deep dive into TCP and UDP protocols, IPv4 and IPv6 then in-depth about Transport, Network and Datalink layers.
My socials: GitHub LinkedIn Twitter Connect with me Folks.
"Thanks for Reading guys!"
