Cisco ONS 15454 Software Feature And Configuration Manual page 181

Chapter 13 Configuring Quality of Service
Command
Step 5
Router(config-pmap-c)# priority
{ 8-2000000 | percent }
Step 6
Router(config-pmap-c)# set cos {0-7}
Note The set-cos-transmit action sets (marks) a VLAN COS priority associated with the packets under/over
the policed rate. The classification of any output policy map will be based on the new COS value set
(even if the packet were to enter and/or exit without a VLAN tag). An output policy map may override
the VLAN COS priority set for the packet. When the packet is transmitted out an interface, the associated
VLAN COS priority will be written into the VLAN tag. If QinQ is used, the top-level VLAN tag at the
time of transmit will be marked. If the packet is transmitted without a VLAN tag, no marking will occur.
When the bandwidth or priority action is used on any class in a policy map, then there must be a class
Note
defined by "match any" which has a bandwidth or priority action in that policy map. This is to ensure
that all traffic can be classified into a default class which has some assigned bandwidth. The hidden class
"class-default" can be used as the "match any" class, and a minimum bandwidth can be assigned to it if
the class is not expected to be used or no reserved bandwidth is desired for default traffic.
When using the bandwidth action, excess traffic (beyond the configured commit) will be allocated any
Note
available bandwidth in proportion to the relative bandwidth commitment of it's traffic class compared to
other traffic classes. Excess traffic from two classes with equal commits will have equal access to
available bandwidth. Excess traffic from a class with a minimum commit might receive only a minimum
share of available bandwidth compared to excess bandwidth from a class with a high commit.
Cisco ONS 15454 SONET/SDH ML-Series Multilayer Ethernet Card Software Feature and Configuration Guide, R4.0
78-15224-02
Purpose
Specifies low latency queuing for the currently selected class. When
the policy-map is applied to an output, an output queue with strict
priority is created for this class. Valid choices are:
• Rate in kilobits per second (8 to 2000000)
Percent of total available bandwidth (1 to 100)
•
If multiple classes and bandwidth actions are specified in a single
policy map, they must use the same choice in specifying bandwidth
(kilobits or percent).
When using the priority action, the traffic in that class is given
Note
a 100% commit (CIR), regardless of the rate entered as the
priority rate. To ensure that CIR commitments are met for the
interface, a policer must be configured on the input of all
interfaces that might deliver traffic to this output class, limiting
the peak rate to the priority rate entered.
This command may only be used in a policy-map applied to an output.
It specifies the VLAN COS priority to set for the outbound packets in
the currently selected class. If QinQ is used, the top-level VLAN tag is
marked. If outbound packets have no VLAN tag, the action has no
effect. This action is applied to the packet after any "set cos" action
done by a policer, and will therefore override the COS set by a policer
action.
Configuring QoS
13-5