# Motivation for IP
## Obiettivi di apprendimento

* get introduced to the concept of an IP-network
* understand that networks can be interconnected
* learn about the importance for decentralization as a design principle
* realize that Local area networks can be fragmented via IP networks

## Trascrizione

There are some limitations over the Ethernet
1) Transport distance should be shorter than 500 meters. So obviously you just can’t create one big Ethernet network. Let’s imagine that we have some geographically distributed networks. And these networks should be interconnected to each other. So you have really small networks that can just add locally in a certain region and you want to interconnect those networks.
2) Collisions. With the non deterministic protocol every time someone wants to sent some data he has to occupy the entire network and if there are too many clients there collisions will arise all the time with the result that no one will be able to pass any message. Another requirement to create Internet was to have it decentralized. When Americans decided to create this communication system they did it mainly for the military reasons. They already knew that if you have 1 single spot where all communications go through it is very easy to attack this spot and then your entire communication doesn’t work.
In decentralized system we can see that if one network fails still all the networks will be at least with some connection to each other. If we will make it like star topology then if one central network fails you are in trouble because your system has no way of communicating anymore. Summing up Internet was designed: - To connect local area networks - To be decentralized not to have a single point of failure - To fragment LAN. So if there too many hosts in LAN you can separate networks.
And in order to achieve all these things an IP was designed. --Jane Kruch (discuss • contribs) 09:31, 31 October 2013 (UTC)

## Ulteriori letture

* Autonomous system
* Internet
* Robustness principle
* Network Segment
* Computer Network
* Internet Protocol

## Discussioni

* Ethernet
** Communication over a shared Medium
** Ethernet header
** Minimum package length vs maximum cable length
** Collision detection
** Summary, further reading, homework
* Internet Protocol
** Motivation for IP
** Classful IPv4 networks
** IP forwarding algorithm
** IP header
** Summary, further reading, homework
* Transmission Control Protocol
** End to end principle and connection oriented communication
** Three way handshake
** Port numbers
** Sliding window and flow control
** Summary, further reading, homework
* Domain Name System
** Tree structure
** Terminology
** Zones
** Review some facts about DNS
** Delegating DNS queries
** DNS address resolution
** Summary, further reading, homework
* Internet vs World Wide Web
** Summary of the internet architecture
** Motivation and requirements for the World Wide Web
** Design principles of the web
** Uniform Resource Identifier
** Summary, further reading, homework
* Hypertext Transfer Protocol
** Making HTTP requests
** A simple web client
** A simple web server
** HTTP header
** Content negotiation
** Summary, further reading, homework
* Web content
** Problem setting for web content formats
** Working with XML
** HTML for web document structures
** Layout elements in HTML
** Motivating separation of content and layout
** Cascading Style Sheets
** Media content
** Metadata
** Summary, further reading, homework
* Dynamic Web Content
** Basics of server side web programming
** Forms and HTTP post request
** Handling a post request in a Java Servlet
** Client side JavaScript
** Ajax and the XMLHttpRequest class
** Summary, further reading, homework