Packet Bursting For Better Performance; Txop Interval For Client Stations; P And Dscp Tags - D-Link DWS-3000 Series User Manual

D-Link Unified Access System
The random backoff used by the access point is a configurable parameter. To describe the random delay, a "Minimum
Contention Window" (MinCW) and a "Maximum Contention Window" (MaxCW) is defined.
• The value specified for the Minimum Contention Window is the upper limit of a range for the initial random backoff wait
time. The number used in the random backoff is initially a random number between 0 and the number defined for the
Minimum Contention Window.
• If the first random backoff time ends before successful transmission of the data frame, the access point increments a
retry counter, and doubles the value of the random backoff window. The value specified in the Maximum Contention
Window is the upper limit for this doubling of the random backoff. This doubling continues until either the data frame is
sent or the Maximum Contention Window size is reached.
P B
ACKET URSTING FOR
The D-Link Unified Access System includes 802.11e based packet bursting technology that increases data throughput and
speed of transmission over the wireless network. Packet bursting enables the transmission of multiple packets without the
extra overhead of header information. The effect of this is to increase network speed and data throughput. The size of packet
bursts allowed (maximum burst length) is a configurable parameter.
TXOP I
NTERVAL FOR
The Transmission Opportunity (TXOP) is an interval of time when a Wi-Fi Multimedia (WMM) client station has the right to
initiate transmissions onto the wireless medium (WM).
802.1 DSCP
P AND
IEEE 802.1p is an extension of the IEEE 802 standard and is responsible for QoS provision. One purpose of 802.1p is to
prioritize network traffic at the data link/ MAC layer.
The 802.1q tag includes a three-bit field for prioritization, which allows packets to be grouped into various traffic classes.
Eight priority levels are defined. The highest priority is seven, which might go to network critical traffic (voice). The lowest
priority level is zero, this is used as a best-effort default, it is invoked automatically when no other value has been set.
Note: IEEE 802.1 prioritization will not work unless QoS and WMM are enabled. WMM must be enabled on both
the AP and on the client connecting to the AP.
<Link>Figure 110 outlines the way in which tags are retrieved and traffic prioritized on a network.
Page 230
B P
ETTER ERFORMANCE
C S
LIENT TATIONS
TAGS
Software User Manual
02/15/2011
Document 34CS3000-SWUM104-D10