Figure 83. CoS Mapping and Queue Configuration
packet A
UserPri=3
packet B
UserPri=7
packet C
(untagged)
packet D
UserPri=6
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.
Ingress
Port 0/10
mode='trust dot1p'
802.1p->COS Q Map
0
2
1
0
2
1
3
5
4
4
5
5
6
5
7
6
port default
priority->traffic class
2
1
Forward via
switch fabric to
egress Port 0/8
21
Class of Service Queuing
Egress
Port 0/8
Q6
B
strict
Q5
D
A
weighted 20%
Q4
weighted 10%
Q3
weighted 5%
Q2
weighted 5%
Q1
weighted 0%
C
Q0
weighted 0%
Packet Transmission order: B, A, D, C
CLI Examples
141