CLI Examples
141
21 Class of Service Queuing
Figure 83.
CoS Mapping and Queue Configuration
Continuing this example, you configured the egress Port 0/8 for strict priority on queue 6, and
a set a weighted scheduling scheme for queues 5-0. Assuming queue 5 has a higher weighting
than queue 1 (relative weight values shown as a percentage, with 0% indicating the bandwidth
is not guaranteed), the queue service order is 6 followed by 5 followed by 1. Assuming each
queue unloads all packets shown in the diagram, the packet transmission order as seen on the
network leading out of Port 0/8 is B, A, D, C. Thus, packet B, with its higher user precedence
than the others, is able to work its way through the device with minimal delay and is
transmitted ahead of the other packets at the egress port.
UserPri=3
packet A
UserPri=7
packet B
(untagged)
packet C
UserPri=6
packet D
ti
m
e
Port 0/10
mode='trust dot1p'
0
2
1
0
2
1
3
5
4
4
5
5
6
5
7
6
802.1p->COS Q Map
port default
priority->traffic class
Port 0/8
A
D
Q6
Q5
strict
weighted 20%
Q4
weighted 10%
Q3
weighted 5%
Q2
weighted 5%
C
Q1
Q0
weighted 0%
weighted 0%
Forward via
switch fabric to
egress Port 0/8
Ingress
Egress
Packet Transmission order: B, A, D, C
2
1
B
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