{{{#!comment
[[Include(wiki:802.11/beta-note)]]
}}}

[[TracNav(802.11/TOC)]]
= 802.11 Reference Design: MAC =

== Overview ==

The MAC implementation is based on the DCF (distributed coordination function) protocol specified in section 9.3 of the 802.11-2012 standard. This design does not implement the PCF (point coordination function) in section 9.4 of the standard. It also does not implement the EDCA (enhanced distributed channel access) in section 9.2.4.2 of the standard.


'''Frames:''' The MAC specification defines many frame formats in section 8 of the 802.11-2012 standard. Our implementation supports a sub-set of these frames.

'''Data/ACK:''' Data and ACK frames are of course supported.

'''Management Frames:''' The following management frames are supported:
 * Beacon
 * Probe Request
 * Probe Response
 * Authentication
 * Deauthentication
 * Association Request
 * Association Response 
 * Reassociation Request
 * Reassociation Response 
 * Disassociation

'''Handshakes:''' The standard defines many inter-node handshakes for many combinations of ad-hoc and infrastructure networks. Our current MAC implementation supports the common association handshake required for a STA (node) to join the network of an AP. This handshake consists of:

||=  STA  =||=  Direction  =||=  AP  =||
||  Probe Request  ||  →  ||  ↓  ||
||  ↓  ||  ←  ||  Probe Response  ||
||  Authentication  ||  →  ||  ↓  || 
||  ↓  ||  ←  ||  Authentication  ||
||  Association Request  ||  →  ||  ↓  || 
||  •  ||  ←  ||  Association Response  ||

'''RTS/CTS:''' The RTS/CTS access mechanism is fully supported by the reference design.

== Architecture ==

The MAC implementation is split into two pieces:
 * The [wiki:./Upper Upper-level MAC] is responsible for inter-packet behaviors that are not time critical
 * The [wiki:./Lower Lower-level MAC] is responsible for intra-packet behaviors that are time critical