Understanding Qos - D-Link DES-3010F Manual

Figure 8- 1. An Example of the Default QoS Mapping on the Switch
The picture above shows the default priority setting for the Switch. Class-3 has the highest priority of the four priority
classes of service on the Switch. In order to implement QoS, the user is required to instruct the Switch to examine the
header of a packet to see if it has the proper identifying tag. Then the user may forward these tagged packets to designated
classes of service on the Switch where they will be emptied, based on priority.
For example, lets say a user wishes to have a video conference between two remotely set computers. The administrator can
add priority tags to the video packets being sent out, utilizing the Access Profile commands. Then, on the receiving end,
the administrator instructs the Switch to examine packets for this tag, acquires the tagged packets and maps them to a class
queue on the Switch. Then in turn, the administrator will set a priority for this queue so that will be emptied before any
other packet is forwarded. This results in the end user receiving all packets sent as quickly as possible, thus prioritizing the
queue and allowing for an uninterrupted stream of packets, which optimizes the use of bandwidth available for the video
conference.

Understanding QoS

The Switch has 5 priority classes of service, one of which is internal and not configurable. These priority classes of service
are labeled as 3, the high class to 0, the lowest class. The eight priority tags, specified in IEEE 802.1p are mapped to the
Switch's priority classes of service as follows:
Priority 0 is assigned to the Switch's Q0 class.
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Priority 1 is assigned to the Switch's Q0 class.
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Priority 2 is assigned to the Switch's Q1 class.
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Priority 3 is assigned to the Switch's Q1 class.
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Priority 4 is assigned to the Switch's Q2 class.
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Priority 5 is assigned to the Switch's Q2 class.
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Priority 6 is assigned to the Switch's Q3 class.
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Priority 7 is assigned to the Switch's Q3 class.
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