Cisco Nexus 7000 Series Configuration Manual page 132

Ingress Queuing
• The match dscp command is applicable only to queues that have at least one CoS value associated with
it. If all DSCP values are not mapped to a nondefault ingress queue, the default queue should have the
CoS values associated with it.
• DSCP queuing is automatically disabled when the user removes all match dscp commands (using no
match statements).
• If the match dscp command is used in the 2q4t-8e-in-q1 class map to set some DSCP values, all remaining
DSCP values are automatically mapped to the default queue.
Bridged Traffic
Cisco Nexus 7000 Series NX-OS Quality of Service Configuration Guide
116
Configuring Queuing and Scheduling on F-Series I/O Modules
When DSCP to ingress queue is enabled, the ingress
queue selection is based on the DSCP value.
However, the egress queue selection is based on
the CoS value of the packet. If a CoS value does
not exist, then all packets are accepted as CoS 0.
To override this behavior and use DSCP for egress
queue selection, an ingress QoS policy has to be
applied that matches the DSCP value and uses the
set dscp value command to set the DSCP to the
same value as the matched DSCP on the class map.
When CoS to ingress queue is enabled, the ingress
queue selection is based on the CoS value. The
egress queue selection is based on the CoS value
of the packet, including non-IP packets. If a CoS
value does not exist, then all packets are accepted
as CoS 0.