TCP and UDP

Transmission Control Protocol (TCP)

Pros

• It sends acknowledgement
• Guaranteed delivery
• Connection Based
• Congestion control
• Ordered Packets

Cons

• Larger packets
• More bandwidth
• Slower than UDP
• Statefull
• Server memory (DOS)

Code

• Go to /TCP run npm i to install all the dependencies
• Run npm run start to run the tcp server (Run the tcp server on a debugger if possible with line 6 as a breakpoint for better understanding)
• Install/Enable telnet in your OS
  • After installing follow these steps
  • Open a new terminal and write telnet 127.0.0.1 8080
  • This will send a tcp request from localhost i.e. 127.0.0.1 to 8080 port, and you will recieve Hello on telnet console
• Try to write on telnet terminal
  • If tcp server running on debugger, it will hit line 6 as data has been sent over, and show the data in debugger
• If you try to kill the server, the telnet will automatically lost the connection with no retained data. This is why TCP is stateful.

User Datagram Protocol (UDP)

Pros

• Smaller Packets
• Less bandwidth
• Faster than TCP
• Stateless

Cons

• No Ack
• No guaranteed delivery
• Connectionless
• No Congestion control
• No ordered packets
• Security

Code

• Go to /UDP and run npm i in your folder's terminal
• You need to install netcat on your os, best way is to do is linux
  • Just do apt-get install netcat, there are other way to install but they are quite lenghty
• Run your server (if possible run in debug mode and add a breakpoint on line 5)
• Go to your wsl terminal and run echo "hi" | nc -w1 -u 127.0.0.1 8081
  • Just echo "hi" will print "hi" in terminal but when added with "|" it pipes the logged "hi" to the netcat server with here is running on port 8081 from netcat port localhost.