Changes between Version 13 and Version 14 of 802.11/MAC/Upper

Timestamp:

Aug 5, 2013, 2:10:00 PM (11 years ago)

Author:

murphpo

Comment:

--

802.11/MAC/Upper

@@ -31 +31 @@
 == State Transitions ==
 
- * {{{Idle}}} → {{{MPDU Tx}}}: This transition occurs when two conditions are met: (a) The [wiki:../Lower lower-level MAC] has indicated that it is ready to receiver another packet for wireless transmission and (b) the transmit queue in the upper-level MAC contains a packet that needs to be sent.
+ * {{{Idle}}} → {{{MPDU Tx}}}: This transition occurs when two conditions are met:
+  1. The [wiki:../Lower lower-level MAC] has indicated that it is ready to receive another packet for wireless transmission and
+  1. The transmit queue in the upper-level MAC contains a packet that is ready for wireless transmission.
 
- * {{{Idle}}} → {{{MPDU Rx}}}: This transition occurs when the [wiki:../Lower low-level MAC] has indicated that a reception has occurred with the following criteria: (a) the received packet is not a control packet (e.g. ACK, RTS, CTS) and (b) the received packet has a receiver address that is either a broadcast packet or a unicast packet whose address matches the MAC address of the node running this software.
+ * {{{Idle}}} → {{{MPDU Rx}}}: This transition occurs when the [wiki:../Lower low-level MAC] has indicated that a reception has occurred which meets the following criteria: 
+  1. The received packet is not a control packet (e.g. ACK, RTS, CTS) and
+  1. The received packet has a receiver address that is either a broadcast packet or a unicast packet whose address matches the local node's MAC address.
 
- * {{{MPDU Rx}}} → {{{Ethernet Tx}}}: This transition occurs when a wireless MPDU data reception occurs that should be de-encapsulated and via Ethernet. ''Note: Unlike the {{{MPDU Tx}}} state, the {{{Ethernet Tx}}} state does not employ a queue. As such, it can be directly accessed from the {{{MPDU Rx}}} state without transitioning through {{{Idle}}}. There is a good reason for this asymmetry: even at the fastest 802.11g rates, wireless packets are much slower than gigabit-per-second wired packets. When receiving a wireless packet, there is enough time to directly transmit a wired packet without halting the next wireless reception. This is not the case for wired receptions, so they must be queued in order to mitigate dropping packets during bursty Ethernet arrivals.''
+ * {{{MPDU Rx}}} → {{{Ethernet Tx}}}: This transition occurs when a wireless MPDU data reception occurs that should be de-encapsulated and sent via Ethernet. The {{{Ethernet Tx}}} state does not employ a queue, as wired transmissions are expected to be much faster than wireless receptions and the wireless PHY does not block while the Ethernet transmission proceeds. This state is entered directly from the {{{MPDU Rx}}} state without transitioning through {{{Idle}}}. 
 
  * {{{Idle}}} → {{{Ethernet Rx}}}: This transition occurs when any packet has been received by the Ethernet MAC on the board.