Internet Technologies and Techniques
Top level of stack
(Application layer protocols, protocol = established agreed way of sharing info)
HTTP, FTP, RTSP, IMAP/POP...
using telnet in terminal to connect to sputnik.media.aalto.fi
Commands in terminal -
telnet sputnik.media.aalto.fi 80
GET http://sputnik.media.aalto.fi/ HTTP/1.0
port 80, default port for HTTP connections. IMAP/POP, port 143
DNS = domain name server, basically a server that knows what name links to what ip address of the server.
For eg. to access sputnik.media.aalto.fi, TLD = top level DNS which redirects to local .fi DNS which would send to aalto DNS so on...
Look up - ICANN,
TCP Transmission control protocol Checks for connections, if everything is ok, errors etc., it guarantees that the information that is requested, will be received in whole without drops etc. retransmits lost packages.
UDP user datagram protocol = gets the data as fast as possible, but no guarantees for drops or right order etc., no error correction.
Internet layer, handles routing of connections , independent of hardware.