https://github.com/hackerkid/the-art-of-network-programming

A handbook on Network Programming in Unix
https://github.com/hackerkid/the-art-of-network-programming

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A handbook on Network Programming in Unix

• Host: GitHub
• URL: https://github.com/hackerkid/the-art-of-network-programming
• Owner: hackerkid
• License: mit
• Created: 2015-07-03T12:14:36.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2015-07-03T13:03:38.000Z (over 9 years ago)
• Last Synced: 2023-08-01T12:24:50.044Z (over 1 year ago)
• Size: 125 KB
• Stars: 1
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
##Sockets

Sockets are used for communicating with other programs with the help of Unix file descriptors. 

There are two types of sockets

* Stream sockets

* Datagram sockets

##Stream Sockets

Stream sockets are mainly used in two way communication. If you send A, B, C through stream socket it will arrive in that particular order. Stream sockets are error free meaning data you send would be always recieved at the other end without any error. This is achived with the help of `TCP` (Transmission Control Protocoal). TCP makes sure that the data which has arrived is sequential and error free. This feature make stream sockets reliable. Stream socket is popularly denoted as `SOCK_STREAM`.

##Datagram Sockets

Datagram sockets unlike Stream sockets is not reliable. The data arrives in no particular order. The advantage of Datagram sockets over stream sockets is the absence of an open connection at the time of transmission. The only thing you need to do is create a packet and send it. Datagram socket don't care about whether the data has been safely recived at the other end. It just keep sending the data. Datagram use `UDP` just like Steam sockets use TCP. Datagram socket can represnted as `SOCK_DGRAM`.

###Packet

A packet is a formatted unit of data carried by a packet-switched network. In simple words you send information over network in the form of small packets. A packet contains two types of data

* Control data

* User data

The control information provides data the network needs to deliver the user data, for example: source and destination network addresses, error detection codes, and sequencing information. Typically, control information is found in packet `headers` and trailers, with payload data in between.

###Why use UDP when it is not reliable?

Sometimes you need to trade reliability for speed. If you are going something like Whatsapp then you should probably use TCP as you don't want to miss any messages. But what would you do while implementing the Uber car tracking system. If you are sending 10 positional updates of the car it doesn't matter if you miss some packets. UDP is good choice here.