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Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
OL-4266-08
Chapter 41 Configuring PFC QoS
Understanding How PFC QoS Works
Figure 41-10
illustrates the drop thresholds for a
1q4t
ingress LAN port. Drop thresholds in other
configurations function similarly.
Figure 41-10 Receive Queue Drop Thresholds
Ingress Queue Types
To see the queue structure of a LAN port, enter the
show queueing interface
{
ethernet
|
fastethernet
|
gigabitethernet
|
tengigabitethernet
}
slot/port
|
include type
command. The command displays one of
the following architectures:
•
1q2t
indicates one standard queue with one configurable tail-drop threshold and one
nonconfigurable tail-drop threshold.
•
1q4t
indicates one standard queue with four configurable tail-drop thresholds.
•
1q8t
indicates one standard queue with eight configurable tail-drop thresholds.
•
2q8t
indicates two standard queues, each with eight configurable tail-drop thresholds.
•
8q4t
indicates eight standard queues, each with four thresholds, each configurable as either
WRED-drop or tail-drop.
•
8q8t
indicates eight standard queues, each with eight thresholds, each configurable as either
WRED-drop or tail-drop.
•
1p1q4t
indicates:
–
One strict-priority queue
–
One standard queue with four configurable tail-drop thresholds.
CoS
0
an
d
1
CoS
2
an
d
3
Co
S
4
an
d
5
C
oS
6
a
nd
7
Traffic is dropped
Drop threshold 4: 100%
Drop threshold 3: 80%
Drop threshold 2: 60%
Drop threshold 1: 50%
Available for
traffic with any
CoS value
Reserved for
CoS 6 and 7
Reserved for
CoS 4 and higher
Reserved for
CoS 2 and higher
Receive queue
(Default values shown)
100% available for CoS 6 and 7
80% available for CoS 4 and 5
60% available for CoS 2 and 3
50% available for CoS 0 and 1
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