wiki:802.11/MAC

Version 3 (modified by chunter, 8 years ago) (diff)

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The 802.11 Reference Design and its documentation are under active development by the Mango team. The current release should be considered a beta- updates with bug fixes, API changes, new features and other refinements will be posted frequently. Please check the downloads page for the latest updates and post any questions about the design to the forums.

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 (it will be soon)

Architecture

The MAC implementation is split into two pieces that each run on their own processor.

  • The High-level MAC? is responsible for inter-packet behaviors that are not time critical
  • The Low-level MAC? is responsible for intra-packet behaviors that are time critical