Networking and Raspi
How to connect with raspberry pi with internet ?
If you want to connect to a network, well the first option you have is to use the wire connection. We're talking about Raspberry Pi B+. B+ has a wired Ethernet jack, RJ45 connector it's called.
How to talk to your Raspi remotely ?
Secure Shell (ssh) is the program that allows you to access the machine remotely.
- Connect your pi with internet.
- Open terminal and write "ifconfig" hit enter you will get all the information of network interface configuration. Note inet addr we will work with this in future. In my case inet addr: 192. 168. 1. 81
- To open the configuration, simply run the following from the command line: "sudo raspi-config".For making SSH enable Goto, Interfacing Options ->SSH->Yes->finish now you are all set.
- Open your laptop or mac if you are in mac just open your terminal and write "ssh pi@192. 168. 1. 81" here pi= username and 192. 168. 1. 81=inet addr of your pi. Now you are connected with your pi.
What is the difference between Network and Internet?
Difference Between Network and Internet is that a network is a collection of computers and devices connected together, often wirelessly, via communications devices and transmission media. The Internet is a worldwide collection of networks that connects millions of businesses, government agencies, educational institutions, and individuals.
How internet connected devices communicate each other ?
Let, pc1 send message "hello" to pc2. Here "hello" is actual data it is called payload. So payload is actual data. so these messages that are sent on the Internet, they have a structure. The internet protocols(Protocols is set of rules) define the standard structure of these messages. You have to put header information before send these message. The header information can be destination address, type of message , size of message etc. There's a lot of data that you might put in the header, but the header is information that's required by the protocol,in order to get the message where it's going to go, and get it there efficiently. Internet Protocol Family, is defined really by a set of protocols. Really, pretty much, three protocols.
IP (internet protocol): Every machine that's on a network has its own IP address. IP deals with host-to-host connections. The communication between those two machines is dealt with by the IP protocol. And all the information that you need to connect between two different machines is going to be contained in the IP part of the header. IP in general is unreliable. What that means is when you send a message to another from one host to another you are not guaranteed that message will arrive. So in addition to IP you're going to use either UDP or TCP.
UDP(User Datagram Protocol): UDP stands for unreliable datagram protocol. It is process to process communications. So what that is, if you remember the IP, IP is host to host, machine to machine. But remember every particular machine can have many processes running on it. Maybe I want a machine I'm running a web browser, I also running World of Warcraft, So those are two processes both communicating on the network. So my World of Warcraft to World of Warcraft communication is different than my web browser to web server communication. So, UDP is Datagram Protocol. It is working at the process-to-process. Example: You can send message Facebook to Facebook but you can not send message Facebook to Skype.
TCP(Transmission Control Protocol): TCP is also process to process communication, just like UDP. And it also uses the same type of process naming, but it's reliable communication. So what that means is if it sends a message, you send a message from one process to another on a different machine, that message is guaranteed to arrive at the destination. Now how does it guarantee this? Basically by retry, so it'll send a message and it'll wait for a response. If it doesn't get the response, it assumes the message didn't arrive so it'll try again and try again and so on.
Md Habibur Rahman