Lars Simon Winzer
61 lines
2.5 KiB
Markdown
61 lines
2.5 KiB
Markdown
# Table of Contents
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- [Table of Contents](#table-of-contents)
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- [Introduction](#introduction)
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- [Formal concepts of networking](#formal-concepts-of-networking)
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- [The Language of the Network](#the-language-of-the-network)
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# Basics
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## Formal concepts of networking
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Whenever you want to access the same data on different devices without carrying it (the data) from device to device, with, let’s say, a thumb drive, you have multiple options for achieving this.
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<!-- I tried to get this embeddet image to show up, but it just wouldnt
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<img src="/documents/images/docs/blog/09-03-26_Network/shared_ressouce_possible_approaches.svg" alt="Peer To Peer Versus Client-Server Architecture" width="200"/>
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-->
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**Peer to Peer** enables users to share content (files, messages, ...).
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While it does not rely on a central server, it comes with the big trade-of that the device storing the data you want to access has to be reachable and online.
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Today Peer to Peer is still widely used with VoIP and decentralized networks for censorship-resistant transactions formaly known as the blockchain.
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The **Client-Server** model evolved into the sophisticated "web-services" we know and use daily.
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One central powerful computer (the server) stores data and allows external devices (clients) to access it.
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For our course "Programmierprojekt" we are required to use the Client-Server model.
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## The Language of the Network
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To communicate over the network, we first need to establish a few rules.
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If we look at the real world, language also follows certain rules:
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* Grammar
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* Meaning of Words
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In computer science, these rules are known as a "protocol." Everyone must follow these rules, because if not, the program we want to communicate with wouldn’t understand us, or in the worst case, misunderstand us.
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For our network, we’ve decided to build upon the Post Office Protocol (POP) version 3. It follows the request-response model, is synchronous, and meets our requirements.
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An example of a request and response (for our game) might look like this:
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1. Request
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```text
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GET_DELTA 42
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```
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2. Response
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```text
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+OK
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PLAYER_FOLDED playerId=3
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POT 240
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NEXT_TURN playerId=1
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WHISPER from=player2 msg="hey"
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CHAT_LOBBY player3="hello"
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.
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```
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The client requests the occurred actions since the 42nd state.
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The server responds with all the actions other players have made and the messages the client has received.
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