Computer Networks

Network Protocol

Set of rules used in digital communication to connect network devices and exchange information b/w them
```
graph LR;
A-->B
B-->A
A--Some set of rules for connection -->B
```

Types

TCP/IP
- TCP:Transmission Control Protocol
- Data transfer
- Base Protocol
- IP: Internet Protocol
```
graph LR;
A>A]--Connect<br/>TCP-->B[(B)]
B--Share<br/>IP-->A
```
HTTP
- Hyper Text Transfer Protocol
- Application Layer
- Web
- WWW
- TCP/IP
- Port: 80
- Request/Response
- Stateless
- Connectionless
- Unencrypted
- HTTP/1.1
- HTTP/2
- HTTP/3
HTTPS
- Hyper Text Transfer Protocol Secure
- Application Layer
- Web
- WWW
- TCP/IP
- Port: 443
- Request/Response
- Stateless
- Connectionless
- Encrypted
- HTTP/1.1
- HTTP/2
- HTTP/3
FTP
- File Transfer Protocol
- Application Layer
- TCP/IP
- Port: 20, 21
- Request/Response
- Stateless
- Connectionless
- Unencrypted
- FTP
- FTPS
- SFTP
SMTP
- Simple Mail Transfer Protocol
- Application Layer
- TCP/IP
- Port: 25
- Request/Response
- Stateless
- Connectionless
- Unencrypted
- SMTP
- SMTPS
- STARTTLS
POP
- Post Office Protocol
- Application Layer
- TCP/IP
- Port: 110
- Request/Response
- Stateless
- Connectionless
- Unencrypted
- POP
- POP3
- POP3S
IMAP
- Internet Message Access Protocol
- Application Layer
- TCP/IP
- Port: 143
- Request/Response
- Stateless
- Connectionless
- Unencrypted
- IMAP
- IMAP3
- IMAP3S
UDP
- User Datagram Protocol
- Connectionless
- Unreliable
- No error checking
- No flow control
- No congestion control
- No sequencing
- No ACK
- No handshake
- No connection
- No state
- No guarantee
- No guarantee of delivery
- No guarantee of order
- No guarantee of duplicate protection
- No guarantee of integrity
- No guarantee of bandwidth
- No guarantee of latency
- No guarantee of jitter
- No guarantee of security
- No guarantee of privacy
- No guarantee of reliability
- No guarantee of availability
- No guarantee of scalability
- No guarantee of maintainability
- No guarantee of interoperability
- No guarantee of portability
- No guarantee of extensibility
- No guarantee of usability
- No guarantee of testability
- No guarantee of reusability
- No guarantee of readability
- No guarantee of writability
- No guarantee of modifiability
- No guarantee of understandability
- No guarantee of traceability
- No guarantee of adaptability
- No guarantee of flexibility
- No guarantee of robustness
- No guarantee of resilience
- No guarantee of reliability
- No guarantee of availability
- No guarantee of security
- No guarantee of safety
- No guarantee of maintainability
- No guarantee of portability
- No guarantee of interoperability
- No guarantee of usability
- No guarantee of testability
- No guarantee of reusability
- No guarantee of readability
- No guarantee of writability
- No guarantee of modifiability
- No guarantee of understandability
- No guarantee of traceability
- No guarantee of adaptability
- No guarantee of flexibility
- No guarantee of robustness
- No guarantee of resilience
- No guarantee of reliability
- No guarantee of availability
PPP
- Point-to-Point Protocol
- Connection-oriented
- Reliable
- Error checking
- Flow control
- Congestion control
- Sequencing
- ACK
- Handshake
- Connection
- State
- Guarantee
- Guarantee of delivery
- Guarantee of order
- Guarantee of duplicate protection
- Guarantee of integrity
- Guarantee of bandwidth
- Guarantee of latency
- Guarantee of jitter
- Guarantee of security
- Guarantee of privacy
- Guarantee of reliability
- Guarantee of availability
- Guarantee of scalability
- Guarantee of maintainability
- Guarantee of interoperability
- Guarantee of portability
- Guarantee of extensibility
- Guarantee of usability
- Guarantee of testability
- Guarantee of reusability
- Guarantee of readability
- Guarantee of writability
- Guarantee of modifiability
- Guarantee of understandability
- Guarantee of traceability
- Guarantee of adaptability
- Guarantee of flexibility
- Guarantee of robustness
- Guarantee of resilience
- Guarantee of reliability
- Guarantee of availability
- Guarantee of security
- Guarantee of safety
- Guarantee of maintainability
- Guarantee of portability
- Guarantee of interoperability
- Guarantee of usability
- Guarantee of testability
- Guarantee of reusability
- Guarantee of readability
- Guarantee of writability
- Guarantee of modifiability
- Guarantee of understandability
- Guarantee of traceability
- Guarantee of adaptability

TCP/IP

TCP is used to transfer data over the internet
TCP divides the data in to small packets and send it to destination through network
IP used for addressing through which data reaches the final destination

HTTP

HTTP is a protocol which is used to transfer data over the web
HTTP is a stateless protocol
HTTP is a connectionless protocol
used in address of web browser before of www
if we type www.google.com in browser then it will send a request to google server and google server will send a response to browser

FTP

FTP is a protocol which is used to transfer files over the internet
FTP is a connection oriented protocol
Uses TCP/IP for data transfer
FTP uses two ports for data transfer
- 20: Data transfer
- 21: Control
FTP uses two modes for data transfer
- Active mode
- Passive mode
FTP uses two types of connections
- Control connection
- Data connection
FTP uses two types of authentication
- Anonymous
- Authenticated
FTP uses two types of data transfer
- ASCII
- Binary
Client requests file from website
Server sends file to client

SMTP

SMTP is a protocol which is used to send emails over the internet
SMTP is a connection oriented protocol
uses TCP/IP for data transfer
There are two more protocols which are used to receive emails
- POP
- IMAP
SMTP uses two ports for data transfer
- 25: Data transfer
- 587: Control

POP

POP is a protocol which is used to receive emails over the internet
POP is a connection oriented protocol
uses TCP/IP for data transfer and helps SMTP from end to end communication
POP uses two ports for data transfer
- 110: Data transfer
- 995: Control

IMAP

IMAP is a protocol which is used to receive emails over the internet
IMAP is a connection oriented protocol
uses TCP/IP for data transfer
IMAP uses two ports for data transfer
actually a mail box which is actually an improvement over POP
by using imap main advantage is that we can retrieve our deleted emails from server
- 143: Data transfer
- 993: Control

UDP

UDP is a protocol which is used to transfer data over the internet
UDP is a connectionless protocol
UDP is a unreliable protocol
UDP is a stateless protocol
UDP is a unencrypted protocol
UDP is a faster than TCP

PPP

used to transfer data between two connected devices

UDP

unreliable and connectionless protocol
in order to send data we don't need to establish connection
UDP is faster than TCP
UDP is used in video streaming
UDP is used in video conferencing
UDP is used in online gaming
used to transfer data in short distance

graph LR;
Protocol-->A(PortNo.)
B>FTP]-->C[(21)]
SMTP-->25
PPP-->110
IMAP-->143
HTTP-->80
HTTPS-->443

TCP vs UDP

	TCP	UDP
Connection	Connection Oriented	Connectionless
Reliability	Reliable	Unreliable
Data Transmission speed	Slow	Fast
Header Size	20 bytes	8 bytes
Packet Size	65,535 bytes	65,535 bytes
Bandwidth Usage	Less	More
Used in	Web, Email, FTP	Video Streaming, Video Conferencing, Online Gaming,DNS
Connection Establishment	Yes	No
Retransmission Of Lost Data	Yes	No
Error Checking	Yes	No
Flow Control	Yes	No
Congestion Control	Yes	No
Sequencing	Yes	No
ACK	Yes	No
Handshake	Yes	No