Table of Contents
Advertisement
Linksys
Linksys
Weighted Round Robin (WRR)—In WRR mode, the number of packets
•
sent from the queue is proportional to the weight of the queue (the
higher the weight the more frames are sent) For example, if there are
a maximum of four queues possible and all four queues are WRR and
the default weights are used, queue 1 receives 1/15 of the bandwidth
(assuming all queues are saturated and there is congestion), queue 2
receives 2/15, queue 3 receives 4/15 and queue 4 receives 8 /15 of the
bandwidth The type of WRR algorithm used in the device is not the
standard Deficit WRR (DWRR), but rather Shaped Deficit WRR (SDWRR)
The queuing modes can be selected in the Queue Scheduling page When the
queuing mode is by strict priority, the priority sets the order in which queues
are serviced, starting with Queue 4 (the highest priority queue) and going to
the next lower queue when each queue is completed
When the queuing mode is Weighted Round Robin, queues are serviced until
their quota has been used up and then another queue is serviced
It is also possible to assign some of the lower queues to WRR, while keeping
some of the higher queues in strict priority In this case, traffic for the strict
priority queues is always sent before traffic from the WRR queues Only after
the strict priority queues have been emptied is traffic from the WRR queues
forwarded (The relative portion from each WRR queue depends on its weight)
To select the priority method and enter WRR data
STEP 1 Click Configuration > Quality of Service > Queue Scheduling
STEP 2 Enter the parameters
Queue—Displays the queue number
•
Scheduling Method: Select one of the following options:
•
Strict Priority—Traffic scheduling for the selected queue and all
•
higher queues is based strictly on the queue priority
WRR—Traffic scheduling for the selected queue is based on WRR The
•
period time is divided between the WRR queues that are not empty,
meaning they have descriptors to egress This happens only if strict
priority queues are empty
WRR Weight—If WRR is selected, enter the WRR weight assigned to
•
the queue
% of WRR Bandwidth—Displays the amount of bandwidth assigned
•
to the queue These values represent the percent of the WRR weight
STEP 3 Click Apply The queues are configured, and the Running
Configuration file is updated
CoS/802.1p to Queue
The CoS/802 1p to Queue page maps 802 1p priorities to egress queues The
CoS/802 1p to Queue Table determines the egress queues of the incoming
packets based on the 802 1p priority in their VLAN Tags For incoming
untagged packets, the 802 1p priority is the default CoS/802 1p priority
assigned to the ingress ports
The following table describes the default mapping:
802 1p Values (0-7,
Queue (4 queues 1-4, 4
7 being the highest)
being the highest priority)
0
1
1
1
2
2
3
3
4
3
5
4
6
4
7
4
By changing the CoS/802 1p to Queue mapping (CoS/802 1p to Queue page),
the Queue schedule method (Queue Scheduling page) and bandwidth
allocation (Bandwidth page), it is possible to achieve the desired quality of
service in a network
The CoS/802 1p to Queue mapping is applicable only if one of the
following exists:
The device is in QoS Basic mode and CoS/802 1p trusted mode
•
Queue 1 has the lowest priority; queue 4 has the highest priority
To map CoS /802 1p values to egress queues:
STEP 1 Click Configure> Quality of Service > CoS/802 1p to Queue
STEP 2 Enter the parameters
Table of Contents
Table of Contents
Notes
Background
Best Effort
Excellent Effort
Critical Application VoIP
phone SIP
Video
Voice Cisco IP phone
default
Interwork Control VoIP
phone RTP
Network Control
94
Advertisement
Table of Contents
