Based on 6.x code, and I believe 7.x but I could be wrong:
f you’re coming from the Nexus 5500 platforms you’re in for a little tweaking to get this working as some things are different. I will quickly outline them and move onto some sample configuration:
- MTU is set on an interface level
- System defined queuing class-maps
- 4 egress queues (0 is default and 1-3 which are already pre-mapped using the above mentioned class-maps)
- Both access and trunk ports, by default, treat all traffic as if it had CoS 0, moving it into the default queue
- QOS ingress service-policy must be applied to ports or port-channels to classify traffic
Here is some basic configuration for setting the QOS policy to classify:
class-map type qos match-all RUBY
match cos 4
class-map type qos match-all EMERALD
match cos 2
class-map type qos match-all DIAMOND
match cos 6
policy-map type qos QOS_POLICY
class RUBY
set qos-group 2
class EMERALD
set qos-group 1
class DIAMOND
set qos-group 3
interface port-channel20
switchport mode trunk
switchport trunk allowed vlan all
spanning-tree port type edge trunk
mtu 9216
service-policy type qos input QOS_POLICY
Now, let’s view the system defined queuing class-maps so you can get an idea of this:
class-map type queuing match-any c-out-q3
Description: Classifier for Egress queue 3
match qos-group 3
class-map type queuing match-any c-out-q2
Description: Classifier for Egress queue 2
match qos-group 2
class-map type queuing match-any c-out-q1
Description: Classifier for Egress queue 1
match qos-group 1
class-map type queuing match-any c-out-q-default
Description: Classifier for Egress default queue
match qos-group 0
Finally, let’s assign some bandwidth allocation around those queues:
policy-map type queuing QUEUING_POLICY
class type queuing c-out-q1
bandwidth percent 10
class type queuing c-out-q2
bandwidth percent 15
class type queuing c-out-q3
bandwidth percent 25
class type queuing c-out-q-default
bandwidth percent 50
Now, we apply this QUEUING policy to the system-qos:
system qos
service-policy type queuing output QUEUING_POLICY
