Section 6: Configuring Quality Of Service; Configuring Class Of Service; Mapping 802.1P Priority - D-Link DWL-8600AP User Manual

D-Link UWS User Manual

Section 6: Configuring Quality of Service

This section gives an overview of Quality of Service (QoS) and explains the QoS features available from the
Quality of Service navigation tree menu, which include the following:
•

"Configuring Class of Service"

• "Configuring Differentiated Services"
• "Configuring Auto VoIP"
In a typical switch, each physical port consists of one or more queues for transmitting packets on the attached
network. Multiple queues per port are often provided to give preference to certain packets over others based
on user-defined criteria. When a packet is queued for transmission in a port, the rate at which it is serviced
depends on how the queue is configured and possibly the amount of traffic present in the other queues of the
port. If a delay is necessary, packets get held in the queue until the scheduler authorizes the queue for
transmission. As queues become full, packets have no place to be held for transmission and get dropped by
the switch.
QoS is a means of providing consistent, predictable data delivery by distinguishing between packets that have
strict timing requirements from those that are more tolerant of delay. Packets with strict timing requirements
are given "special treatment" in a QoS capable network. With this in mind, all elements of the network must
be QoS-capable. The presence of at least one node which is not QoS-capable creates a deficiency in the
network path and the performance of the entire packet flow is compromised.
Configuring Class of Service
The Class of Service (CoS) queueing feature lets you directly configure certain aspects of switch queueing. This
provides the desired QoS behavior for different types of network traffic when the complexities of DiffServ are
not required. The priority of a packet arriving at an interface can be used to steer the packet to the appropriate
outbound CoS queue through a mapping table. CoS queue characteristics that affect queue mapping, such as
minimum guaranteed bandwidth, transmission rate shaping, etc., are user-configurable at the queue (or port)
level. The system supports eight (0 to 7) queues per port.

Mapping 802.1p Priority

The IEEE 802.1p feature allows traffic prioritization at the MAC level. The switch can prioritize traffic based on
the 802.1p tag attached to the L2 frame. Each port on the switch has multiple queues to give preference to
certain packets over others based on the class of service (CoS) criteria you specify. When a packet is queued
for transmission in a port, the rate at which it is serviced depends on how the queue is configured and possibly
the amount of traffic present in the other queues of the port. If a delay is necessary, packets get held in the
queue until the scheduler authorizes the queue for transmission.
Use the 802.1p Priority Mapping page in the Class of Service folder to assign 802.1p priority values to various
traffic classes on one or more interfaces.
D-Link
Oct. 2015
Configuring Quality of Service
Unified Wired and Wireless Access System
Page 334