wiki:802.11/MAC

Version 7 (modified by chunter, 7 years ago) (diff)

--

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.

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: Support for the RTS/CTS handshake is not currently implemented (we may add this in a future release)

Architecture

The MAC implementation is split into two pieces:

  • The Upper-level MAC is responsible for inter-packet behaviors that are not time critical
  • The Lower-level MAC is responsible for intra-packet behaviors that are time critical