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Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
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Chapter 31 Configuring PFC QoS
PFC QoS Default Configuration
With PFC QoS enabled
Ingress LAN port trust state Untrusted
2q2t transmit-queue size percentages
• Low priority: 80%
• High priority: 20%
1p2q2t transmit-queue size percentages
• Low priority: 70%
• High priority: 15%
• Strict priority 15%
1p2q1t transmit-queue size percentages
• Low priority: 70%
• High priority: 15%
• Strict priority 15%
1p2q1t standard transmit-queue low:high
priority bandwidth allocation ratio
100:255
2q2t, 1p2q2t, and 1p2q1t standard
transmit-queue low:high priority
bandwidth allocation ratio
5:255
1p3q1t standard transmit-queue
low:medium:high-priority bandwidth
allocation ratio
100:150:255
1q4t/2q2t receive and transmit-queue
CoS value and drop-threshold mapping
Receive queue 1/drop threshold 1 (50%) and
transmit queue 1/drop threshold 1 (80%)—CoS 0 and 1
Receive queue 1/drop threshold 2 (60%) and
transmit queue 1/drop threshold 2 (100%)—CoS 2 and 3
Receive queue 1/drop threshold 3 (80%) and
transmit queue 2/drop threshold 1 (80%)—CoS 4 and 5
Receive queue 1/drop threshold 4 (100%) and
transmit queue 2/drop threshold 2 (100%)—CoS 6 and 7
1q2t port receive-queue CoS
value/drop-threshold mapping and
threshold percentages
Receive queue 1:
• Threshold 1:
–
CoS 0, 1, 2, 3, and 4
–
Tail-drop threshold: 80%
• Threshold 2:
–
CoS 5, 6, and 7
–
Tail-drop threshold: 100% (not configurable)
Table 31-2 PFC QoS Default Configuration (continued)
Feature Default Value
