Cisco WS-X6066-SLB-APC - Content Switching Module Software Manual page 732

Understanding How QoS Works
2q2t Ports
For 2q2t ports, each transmit queue has two drop thresholds that function as follows:
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1p2q2t Ports
For 1p2q2t ports, the low- and high-priority standard transmit queues each have two drop thresholds that
function as follows:
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1p3q1t Ports
For 1p3q1t ports, the queues each have one drop threshold that function as follows:
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Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
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Frames with CoS 0, 1, 2, or 3 go to the low-priority transmit queue (queue 1):
Using transmit queue 1, drop-threshold 1, the switch drops frames with CoS 0 or 1 when the
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low-priority transmit-queue buffer is 80 percent full.
Using transmit queue 1, drop threshold 2, the switch drops frames with CoS 2 or 3 when the
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low-priority transmit-queue buffer is 100 percent full.
Frames with CoS 4, 5, 6, or 7 go to the high-priority transmit queue (queue 2):
Using transmit queue 2, drop threshold 1, the switch drops frames with CoS 4 or 5 when the
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high-priority transmit-queue buffer is 80 percent full.
Using transmit queue 2, drop threshold 2, the switch drops frames with CoS 6 or 7 when the
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high-priority transmit-queue buffer is 100 percent full.
Frames with CoS 0, 1, 2, or 3 go to the low-priority standard transmit queue (queue 1):
Using standard transmit queue 1, drop threshold 1, the switch drops frames with CoS 0 or 1
–
when the low-priority transmit-queue buffer is 80 percent full.
Using standard transmit queue 1, drop threshold 2, the switch drops frames with CoS 2 or 3
–
when the low-priority transmit-queue buffer is 100 percent full.
Frames with CoS 4, 6, or 7 go to the high-priority standard transmit queue (queue 2):
Using standard transmit queue 2, drop threshold 1, the switch drops frames with CoS 4 when
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the high-priority transmit-queue buffer is 80 percent full.
Using standard transmit queue 2, drop threshold 2, the switch drops frames with CoS 6 or 7
–
when the high-priority transmit-queue buffer is 100 percent full.
Frames with CoS 5 go to the strict-priority transmit queue (queue 3), where the switch drops frames
only when the buffer is 100 percent full.
Frames with CoS 0 and 1 go to the low-priority standard transmit queue (queue 1).
Frames with CoS 2, 3, or 4 go to the medium-priority standard transmit queue (queue 2).
Chapter 41 Configuring QoS
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