Block acknowledgement
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[edit] Block Acknowledgment
It is a feature in IEEE 802.11-2007 Standard and 802.11n Draft to allow acknowledgement of a group of frames instead of a single frame (as previously used in 802.11a/b).
There are mainly two commands to establish a Block Acknowledgement agreement:
ADDBA: To establish a BlockAck agreement.
DELBA: To turn down a BlockAck agreement.
Once the agreement has been established, there are two types of Block Acks:
1. Immediate BlockAck
2. Delayed BlockAck
The frames used in these agreements are:
BAR (Block Acknowledgement Request)
To request an acknowledgement to the recipient station, confirming that has received a block of frames.
and
BA (Block Acknowledgement) response
The confirmation from the recipient station, stating which frames have been received, this is explicitly mentioned in a matrix (part of the BAR) call the "bit map".
As the time of writing, current version of 802.11n unapproved standard (D3.01) includes a new type ob BlockAck called "HT Immediate BlockAck".
[edit] External links
- Status of the project 802.11n IEEE Task Group TGn
