Enterprise QoS Solution Reference Network Design Guide
Enterprise QoS Solution Reference Network Design Guide
Enterprise QoS Solution Reference Network Design Guide
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Catalyst 6500 PFC2/PFC3—<strong>QoS</strong> Considerations and <strong>Design</strong><br />
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<strong>Enterprise</strong> <strong>QoS</strong> <strong>Solution</strong> <strong>Reference</strong> <strong>Network</strong> <strong>Design</strong> <strong>Guide</strong><br />
Chapter 2 Campus <strong>QoS</strong> <strong>Design</strong><br />
In IOS, the 1P3Q1T, 1P3Q8T, and 1P7Q8T queuing structures can be configured to use tail-drop or<br />
WRED. By default, WRED is disabled. Therefore, it is good practice to always explicitly enable WRED<br />
on a queue before setting WRED thresholds for these queuing structures.<br />
Additionally, in Cisco IOS, the 1P3Q1T queuing structure does not support mapping CoS values to the<br />
tail of the queue (only to the single WRED threshold). Therefore, the queuing recommendation requires<br />
slight alterations for Cisco IOS: changing all three WRED thresholds to 80:100 and mapping CoS values<br />
2, 3, 4, 6, and 7 to Q3T1.<br />
The Catalyst 6500 IOS configurations to configure 1P3Q1T queuing recommendations are shown below.<br />
Example 2-74 Catalyst 6500 IOS—1P3Q1T Queuing Example<br />
CAT6500-PFC3-IOS(config)# interface range FastEthernet3/1 - 48<br />
CAT6500-PFC3-IOS(config-if)# wrr-queue bandwidth 5 25 70<br />
! Sets the WRR weights for 5:25:70 (Q1:Q2:Q3) bandwidth servicing<br />
CAT6500-PFC3-IOS(config-if)#<br />
CAT6500-PFC3-IOS(config-if)#<br />
CAT6500-PFC3(config-if-range)# wrr-queue random-detect 1<br />
! Enables WRED on Q1<br />
CAT6500-PFC3(config-if-range)# wrr-queue random-detect 2<br />
! Enables WRED on Q2<br />
CAT6500-PFC3(config-if-range)# wrr-queue random-detect 3<br />
! Enables WRED on Q3<br />
CAT6500-PFC3-IOS(config-if)#<br />
CAT6500-PFC3-IOS(config-if)# wrr-queue random-detect min-threshold 1 80<br />
! Sets Min WRED Threshold for Q1T1 to 80%<br />
CAT6500-PFC3-IOS(config-if)# wrr-queue random-detect max-threshold 1 100<br />
! Sets Max WRED Threshold for Q1T1 to 100%<br />
CAT6500-PFC3-IOS(config-if)#<br />
CAT6500-PFC3-IOS(config-if)# wrr-queue random-detect min-threshold 2 80<br />
! Sets Min WRED Threshold for Q2T1 to 80%<br />
CAT6500-PFC3-IOS(config-if)# wrr-queue random-detect max-threshold 2 100<br />
! Sets Max WRED Threshold for Q2T1 to 100%<br />
CAT6500-PFC3-IOS(config-if)#<br />
CAT6500-PFC3-IOS(config-if)# wrr-queue random-detect min-threshold 3 80<br />
! Sets Min WRED Threshold for Q3T1 to 80%<br />
CAT6500-PFC3-IOS(config-if)# wrr-queue random-detect max-threshold 3 100<br />
! Sets Max WRED Threshold for Q3T1 to 100%<br />
CAT6500-PFC3-IOS(config-if)#<br />
CAT6500-PFC3-IOS(config-if)# wrr-queue cos-map 1 1 1<br />
! Assigns Scavenger/Bulk to Q1 WRED Threshold 1 (80:100)<br />
CAT6500-PFC3-IOS(config-if)# wrr-queue cos-map 2 1 0<br />
! Assigns Best Effort to Q2 WRED Threshold 1 (80:100)<br />
CAT6500-PFC3-IOS(config-if)# wrr-queue cos-map 3 1 2 3 4 6 7<br />
! Assigns CoS 2,3,4,6 and 7 to Q3 WRED Threshold 1 (80:100)<br />
CAT6500-PFC3-IOS(config-if)# priority-queue cos-map 1 5<br />
! Assigns VoIP to PQ (Q4)<br />
CAT6500-PFC3-IOS(config-if)#end<br />
CAT6500-PFC3-IOS#<br />
Catalyst 6500 MLS <strong>QoS</strong> Verification Commands:<br />
show queueing interface<br />
Catalyst 6500—1P3Q8T Queuing and Dropping<br />
The 1P3Q8T queuing structure is identical to the 1P3Q1T structure, except it has eight tunable WRED<br />
thresholds per queue (instead of one) and it also supports tuning the Transmit Size Ratios. Under this<br />
model, Q4 is the strict-priority queue.<br />
Version 3.3
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