three way handshaking and four way handshaking with half close option for connection termination

Question

Explain three way handshaking and four way handshaking with half close option for connection termination

what is this four way handshaking and how connection termination takes place please explain??

Answer 1

For 3 way handshake refer :http://www.omnisecu.com/tcpip/tcp-three-way-handshake.php

The WPA2 standard for wireless uses a four-way handshake defined in IEEE 802.11i-2004

The four-way handshake is designed so that the access point (or authenticator) and wireless client (or supplicant) can independently prove to each other that they know the PSK(pre-shared key)/PMK( Pairwise Master Key), without ever disclosing the key.

For More Information visit this link.https://en.wikipedia.org/wiki/IEEE_802.11i-2004

Comments

Dear sir please tell about half close option for connection termination

what is this half close option ?

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Every TCP connection consists of two half-connection which are closed independently of each other. So if one end sends a FIN, then the other end is free to just ACK that FIN (instead of FIN+ACK-ing it), which signals the FIN-sending end that it still has data to send. So both ends end up in a stable data transfer state other than ESTABLISHED--namely FIN_WAIT_2 (for the receiving end) and CLOSE_WAIT (for the sending end). Such a connection is said to be half closed and TCP is actually designed to support those scenarios, so half closed connections is a TCP feature.
for more information visit this link : http://www.vorlesungen.uni-osnabrueck.de/informatik/networking-programming/notes/22Nov96/3.html