TCP/IP model
This is a special case OSI model, because it contains less levels.
Application
Transport
This is basically OSI Transport, Session and a bit of Application layers.
Connection oriented protocols: TCP
Connectionless protocols: UDP (DNS and DHCP use UDP)
Data comes from Application layer => Transport layer breaks the data into chunks, adds info about ports, checksums (creates TCP segment) => hand TCP segment to Internet layer, which creates IP packet out of it.
netstat -n to check sessions
Internet
"IP packet layer". Any device or protocol which deal with IP packets:
getting IP packet to its destination
create IP packet
Protocols on this layer:
IPv4
IPv6
ICMP
Link/Network interface
Actually joins layers 1 and 2 from OSI.
Cabling, physical address, NICs, switches.
Ethernet Frames are used on this level (PDU - protocol data unit).
How ComputerA will realise MAC address of ComputerB?
ComputerA will send a ARP request to FF-FF-FF-FF-FF-FF MAC address (universal broadcast MAC address) and then ComputerB will send ARP reply. After this ComputerA will send Ethernet frames.
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