What all happens in background when i get connected to internet.(processes N protocols)?

Question

anybody explain in detail.

Answer 1

Part 1:
Well, there is a.difference between connecting to local network and to internet. I will say only things that most devices have in common (not like windows home group etc.).

When you connect to local network (plug in your cable) your computer sends DHCP request asking for it's address (that includes computer's MAC address to identify it). When any running DHCP server captures it (most times it runs on routers) it sends response containing IP address for computer, network mask (sometimes in different format called network prefix lengh), default gateway and DNS server(s)

The computer IP address: It is only for local network. It is used to identify to with computer on local network is message addresed (example IPv4 address: 192.168.1.2)

Network mask says what all IP addresses shoud be considered as local (mask 255.255.255.0 in combination with ip address 192.168.1.2 says that local are computers at 192.168.1.0-255)
(network prefix len of 24 is the same as above: IPv4 have 4 parts each of lengh of 8 bits (2^8=256 combinations) so 24 means first 3 parts are local network prefix)

Answer 2

Part 2: (too large for one answer)
Default gateway says trough with local node computer shoud do request outside local network (i.e. to internet). This is 99% of the time router With uses NAT (Network Address Translation) to connect local client to global server.

DNS server(s) are used to translate DNS name(s) to global IP addresses. For example when user enters "https://www.google.com/search?q=test" into browser this happens:
1) DNS server is asked to resolve name "www.google.com".
In my case servers responds with IP address 216.58.209.164
2) protocol is httpS so browser trys to establish secure SSL connection on resolved server
3) an GET HTTP request on page "search" is send with parameter "q" (query) of value "test" (note: also all site-specific cookies are sent now) over perviously created SSL tunnel and receives the HTML page

Hope this helped at least a bit. I was not 100% sure what you were asking for, so if you want to know more, feel free to do so. Also sorry for grammar.