Product Manual
Product Manual
Product Manual
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Scheduling<br />
DES-3526 / DES-3526DC Fast Ethernet Layer 2 Switch<br />
Changing the output scheduling used for the hardware queues in the Switch can customize QoS. As<br />
with any changes to QoS implementation, careful consideration should be given to how network<br />
traffic in lower priority queues is affected. Changes in scheduling may result in unacceptable levels of<br />
packet loss or significant transmission delay. If you choose to customize this setting, it is important to<br />
monitor network performance, especially during peak demand, as bottlenecks can quickly develop if<br />
the QoS settings are not suitable. In the Configuration folder open the QoS folder and click QoS<br />
Output Scheduling, to view the window shown below.<br />
Figure 6- 44. QoS Output Scheduling window<br />
You may assign the following values to the QoS classes to set the scheduling.<br />
Parameter Description<br />
Max. Packets (0-255) Specifies the maximum number of packets the above specified hardware priority<br />
queue would be allowed to transmit before allowing the next lowest priority queue<br />
to transmit its packets. A value between 0 and 255 can be specified.<br />
Max. Latency (0-255) Specifies the maximum amount of time the above specified hardware priority<br />
queue will be allowed to transmit packets before allowing the next lowest<br />
hardware priority queue to begin transmitting its packets. A value between 0 and<br />
255 can be specified - with this value multiplied by 16 ms to arrive at the total<br />
allowed time for the queue to transmit packets. For example, a value of 3<br />
specifies 3 X 16 = 48 ms. The queue will continue transmitting the last packet until<br />
it is finished when the max latency timer expires.<br />
Click Apply to implement changes made.<br />
802.1p Default Priority<br />
NOTE: The settings you assign to the queues, numbers 0-7, represent<br />
the IEEE 802.1p priority tag number. Do not confuse these settings<br />
with port numbers.<br />
The Switch allows the assignment of a default 802.1p priority to each port on the Switch. In the<br />
Configuration folder open the QoS folder and click 802.1p Default Priority, to view the window<br />
shown below.<br />
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