Chapter 7, Problem P7P

Program Plan Intro

IEEE 802.11:

• IEEE 802.11 stands for wireless LAN that was ratified by the Institute of Electrical and Electronics Engineering.
• There are many 802.11 standards for wireless LAN technology in the IEEE 802.11. The different 802.11 standards all share some common characteristics.
• Basic service set (BSS) is a fundamental building block of 802.11 architecture. The BSS also known as Access Point (AP).
• Every wireless station in 802.11 wants to associate with an access point before it can send or receive network layer data.

DIFS:

DIFS stands for DCF Interframe Spacing. It is a time delay for which sender wait after finishing its back off, previously sending RTS package.

SIFS:

SIFS stands for Shortest Interframe Spacing and it is consider as shortest among above mention networking technology.

Request to send (RTS)/ clear to send (CTS):

• The optimal mechanism used by the IEEE 802.11 is RTS. This is used to decreasing the frame collisions which was introduced by the hidden node problem.
• In order to avoid the collisions problem, the IEEE 802.11 protocol allows a station to use Request to Send (RTS) and Clear to Send (CTS) control frames to reserve access to the channel.
• When a sender want to send a data frame, it can initial send an RTS frame to the AP. After AP receives the RTS frame, it will responds by broadcasting a CTS frame.