Cisco Systems EA6500 Manual De Usuario

For 2q2t ports, each transmit queue has two tail-drop thresholds that function as follows:

Frames with CoS 0, 1, 2, or 3 go to the low-priority transmit queue (queue 1):

Using transmit queue 1, tail-drop threshold 1, the switch drops frames with CoS 0 or 1 when the 
low-priority transmit-queue buffer is 80 percent full.

Using transmit queue 1, tail-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, 5, 6, or 7 go to the high-priority transmit queue (queue 2):

Using transmit queue 2, tail-drop threshold 1, the switch drops frames with CoS 4 or 5 when the 
high-priority transmit-queue buffer is 80 percent full.

Using transmit queue 2, tail-drop threshold 2, the switch drops frames with CoS 6 or 7 when the 
high-priority transmit-queue buffer is 100 percent full.

1p2q2t ports have a strict-priority queue and two standard transmit queues. The two standard transmit 
queues each have two WRED-drop thresholds.

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, 1, 2, or 3 go to the low-priority standard transmit queue (queue 1):

Using standard transmit queue 1, WRED-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, WRED-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, WRED-drop threshold 1, the switch drops frames with CoS 4 
when the high-priority transmit-queue buffer is 80 percent full.

Using standard transmit queue 2, WRED-drop threshold 2, the switch drops frames with CoS 6 
or 7 when the high-priority transmit-queue buffer is 100 percent full.

1p3q1t ports have a strict-priority queue and three standard transmit queues. The standard transmit 
queues each have one WRED-drop threshold and one nonconfigurable tail-drop threshold.

Frames with CoS 5 go to the strict-priority transmit queue (queue 4), 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).

Frames with CoS 6 or 7 go to the high-priority standard transmit queue (queue 3).

You can configure each standard transmit queue to use both a non-configurable 100 percent 
tail-drop threshold and a configurable WRED-drop threshold (see the