Section 3
Configuration
3-52
WR850
Field Description
No-
Acknowledgement:
(ADVANCED)
Enables No-Acknowledgment operation in WMM, entrusting that
the WR850 and clients can share prioritization settings without
the need to transmit acknowledgement messages.
Disabling acknowledgement messages can free up wireless
network capacity but can increase opportunities for errors if
strong wireless connections are not established between the
WR850 and all WMM-enabled clients.
•
Selecting
On
entrusts that prioritization can occur without
acknowledgement messages.
•
Selecting
Off
mandates acknowledgement messages.
FACTORY DEFAULT:
Off
EDCA AP and
Client Parameters:
(ADVANCED)
WMM uses a protocol called Enhanced Distributed Channel
Access (EDCA) to prioritize traffic on the wireless network.
EDCA requires that wireless devices assign each intended
transmission a priority, within an Access Category (AC).
WMM defines 4 Access Categories:
•
Voice
, to give voice traffic the highest priority, since it has
the least tolerance for delays and/or loss of data.
•
Video
, to give video a higher priority than other traffic,
and optimize real-time video display.
•
Best Effort
, for legacy devices, and/or any other traffic
sensitive to delays (e.g., general Internet surfing).
•
Background
, for lowest priority traffic with limited
sensitivity to delays (e.g., printing).
EDCA manages queues of transmissions within each of these
ACs, allocating “slots” of time (or “transmit opportunities”) to
each, based on three prioritization settings, set per AC:
•
Arbitrary Inter-Frame Space Number (AISFN),
a
minimum number of “slots” a transmission will wait in
between transmission opportunities.
•
Contention Window (CW)
, a minimum and maximum
number of “slots” randomly added to the AIFSN, in order
to minimize conflicts between transmissions.
•
Transmit Opportunity Limit (TXOP limit)
, the length of
time allocated to a transmission one it reaches the top of
a queue. For example, video is typically given larger
TXOP limits because it is more data-intensive.
The WR850 manages EDCA prioritization across the network.
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