{{{#!comment [[Include(wiki:802.11/beta-note)]] }}} [[TracNav(802.11/TOC)]] = Access Point = The Access Point implementation in the Mango 802.11 Reference Design allows 802.11 stations to associate and bridge their traffic over the Ethernet port of a WARP v3 kit. || [[Image(wiki:802.11/files:AP_top.png, width=600)]] || || '''Top-level view of AP States''' || There are three broad classes of events that pull the AP implementation out of an idle state. Those classes are: 1. Wireless MPDU Receptions 1. Ethernet Frame Receptions 1. Scheduled Events In our implementation, each of these state transitions occurs via an interrupt. == Wireless MPDU Receptions == || [[Image(wiki:802.11/files:AP_mpdu_rx.png, width=600)]] || || '''MPDU Reception States''' || When receiving a wireless MPDU, an 802.11 AP must filter on the type of packet and where it came from (i.e. transmitter address TA). In the event that the received MPDU is a data frame intended to be delivered to the wired Ethernet portal, it is passed off to the MAC High Framework's [wiki:../MACHighFramework/EthEncap Ethernet de-encapsulation] function before being transmitted via the Ethernet MAC and PHY. When a received MPDU is one of the many [http://en.wikipedia.org/wiki/IEEE_802.11#Management_Frames management frametypes], the AP honors the 802.11 standard's protocol for handshakes during the association process. This handshake is visualized in the above state diagram. == Ethernet Frame Receptions == || [[Image(wiki:802.11/files:AP_eth_rx.png, width=600)]] || || '''Ethernet Reception States''' || Ethernet frame receptions come from the Ethernet portal and are delivered to some subset of the wireless stations associated with the AP. If the received Ethernet frame is destined for a broadcast hardware address, the AP sends the frame with a broadcast receiver address (RA) such that all associated nodes can decode it. When the Ethernet frame is destined for a unicast address, the AP only forwards the packet if that address has been associated with the AP. If not, it will throw the packet away. == Scheduled Events == || [[Image(wiki:802.11/files:AP_sched.png, width=600)]] || || '''Scheduled Events''' || In addition to processing wired and wireless receptions, the AP must also deal with scheduled events. For example, at boot, the AP sets up a schedule to periodically transmit a beacon frame. Additionally, it periodically culls through the current list of associated devices and manually removes and deauthenticates any devices that have been idle for too long.