Coordinating Traffic Flow; Qos Queues And Dscp On Packets - D-Link DWS-3024 User Manual

D-Link Unified Access System User Manual
The D-Link Access Points provide QoS based on the Wireless Multimedia (WMM)
specification, which implements a subset of
Both access points and wireless clients (laptops, consumer electronics products) can be
WMM-enabled by the Wi-Fi Alliance.

Coordinating Traffic Flow

Configuring QoS options on the D-Link Unified Access System consists of setting parameters
on existing queues for different types of wireless traffic. You can configure different minimum
and maximum wait times for the transmission of packets in each queue based on the
requirements of the media being sent. Queues automatically provide minimum transmission
delay for Voice, Video, multimedia, and mission critical applications, and rely on best-effort
parameters for traditional IP data.
For example, time-sensitive Voice, Video, and multimedia are given effectively higher priority
for transmission (lower wait times for channel access), while other applications and traditional
IP data which are less time-sensitive but often more data-intensive are expected to tolerate
longer wait times.
The D-Link Unified Access System implements QoS based on the IEEE Wireless Multimedia
(WMM) standard. A Linux-based queuing class is used to tag packets and establish multiple
queues. The queues provided offer built-in prioritization and routing based on the type of data
being transmitted.
The Administration UI provides a way for you to configure parameters on the queues.

QoS Queues and DSCP on Packets

QoS on the D-Link Unified Access System leverages
header related to Diff-Serv Code Point (DSCP). Every IP packet sent over the network
includes a DSCP field in the header that indicates how the data should be prioritized and
transmitted over the network. The DSCP field consists of a 6 bit value defined by the local
administration. For WMM, Wi-Fi Alliance suggests a particular mapping for DSCP values
The access point examines the DSCP field in the headers of all packets that pass through the
AP. Based on the value in a packet's DSCP field, the AP prioritizes the packet for transmission
by assigning it to one of the queues. This process occurs automatically, regardless of whether
you deliberately configure QoS or not.
A different type of data is associated with each queue. The queue and associated priorities and
parameters for transmission are as follows:
• Data 0 (Voice). Highest priority queue, minimum delay. Time-sensitive data such as Voice
over IP (VoIP) is automatically sent to this queue.
• Data 1 (Video). High priority queue, minimum delay. Time-sensitive data such as Video
and other streaming media are automatically sent to this queue.
• Data 2 (Best Effort). Medium priority queue, medium throughput and delay. Most
traditional IP data is sent to this queue.
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802.11e features.
WMM information in the IP packet