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This chapter contains the following sections:
Information About Interface QoS
The trust boundary is enforced by the incoming interface as follows:
All Fibre Channel and virtual Fibre Channel interfaces are automatically classified into the FCoE system class.
By default, all Ethernet interfaces are trusted interfaces.The 802.1p CoS and DSCP are preserved unless the marking is configured. There is no default CoS to queue and DSCP to queue mapping. You can define and apply a policy to create these mappings. By default, without a user defined policy, all traffic is assigned to the default queue.
Any packet that is not tagged with an 802.1p CoS value is classified into the default drop system class. If the untagged packet is sent over a trunk, it is tagged with the default untagged CoS value, which is zero.
You can override the default untagged CoS value for an Ethernet interface or port channel.
You can override the default untagged CoS value for an Ethernet interface or a port channel interface using the untagged cos cos-value command.
You can override the default untagged Cos value for an Ethernet or a Layer 3 interface or a port channel interface using the untagged cos cos-value command.
After the system applies the untagged CoS value, QoS functions the same as for a packet that entered the system tagged with the CoS value.
The egress queues are not configurable for native Fibre Channel interfaces. Two queues are available as follows:
Configuring Interface QoS
Any incoming packet not tagged with an 802.1p CoS value is assigned the default untagged CoS value of zero (which maps to the default Ethernet drop system class). You can override the default untagged CoS value for an Ethernet or EtherChannel interface.
You can configure flow control on a Layer 2 or Layer 3 interface. Use the no switchport command to configure a Layer 3 interface
On a Cisco Nexus device, you can configure a type qos policy map and untagged CoS on the same interface.
The following example shows how to set the CoS value to 4 for untagged frames received on an interface:
switch# configure terminal switch(config)# interface ethernet 1/2 switch(config-if)# untagged cos 4
The following example shows how to set the CoS value to 3 for untagged frames received on a Layer 3 interface:
switch# configure terminal switch(config)# interface ethernet 1/5 switch(config-if) no switchport switch(config-if)# untagged cos 3 switch(config-if)#
An input qos policy is a service policy applied to incoming traffic on an Ethernet interface for classification. For type queuing, the output policy is applied to all outgoing traffic that matches the specified class. When you configure an input queuing policy on an interface or EtherChannel, the switch sends the configuration data to the adapter using the DCBX protocol.
Note | Type qos policies can be activated only on Cisco Nexus device interfaces and Cisco Nexus Fabric Extender host interfaces. Type qos policies are not supported on Fabric Extender fabric interfaces or Fabric Extender fabric EtherChannel interfaces. |
Command or Action | Purpose | |||||
---|---|---|---|---|---|---|
Step 1 |
switch#
configure
terminal
|
Enters global configuration mode. | ||||
Step 2 |
switch(config)#
interface {ethernet [chassis/]slot/port |
port-channel
channel-number}
|
Enters the configuration mode for the specified interface.
| ||||
Step 3 |
switch(config-if)#
service-policy [type {qos |
queuing}] [input |
output]policy-name
|
Specifies the policy map to use as the service policy for the system. There are two policy-map configuration modes:
| ||||
Step 4 |
switch(config-if)#
service-policy input
policy-name
|
Applies the policy map to the interface.
|
This example shows how to apply a policy to an Ethernet interface:
switch# configure terminal
switch(config)# interface ethernet 1/1
switch(config-if)# service-policy type qos input policy1
You can configure a service policy for a Layer 3 interface.
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. | ||
Step 2 |
switch(config)#
interface
ethernet
slot/port
|
Enters the configuration mode for the specified interface.
| ||
Step 3 |
switch(config-if)#
no
switchport
|
Selects the Layer 3 interface. |
The following example shows how to attach a queuing policy map to a Layer 3 interface:
switch# configure terminal switch(config)# interface ethernet 1/5 switch(config-if)# no switchport switch(config-if)# service-policy type queuing output my_output_q_policy switch(config-if)#
The following example shows how to attach an input qos policy map to a Layer 3 interface:
switch# configure terminal switch(config)# interface ethernet 1/5 switch(config-if)# no switchport switch(config-if)# service-policy type qos input my_input_qos_policy switch(config-if)#
You can change the bandwidth allocated to unicast and multicast traffic by assigning weighted round-robin (WRR) weights as a percentage of the interface data rate to the egress queues.
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. | ||
Step 2 |
switch(config)#
interface
ethernet
slot/port
|
Enters configuration mode for the specified interface.
| ||
Step 3 |
switch(config-if)#
wrr
unicast-bandwidth
percentage-value
|
Changes the bandwidth allocated to unicast and multicast traffic on traffic congestion. The bandwidth-value percentage ranges from 0 to 100 percent. |
This example shows how to attach a queuing policy map to a Layer 3 interface:
switch# configure terminal switch(config)# interface ethernet 1/5 switch(config-if)# wrr unicast-bandwidth 75 switch(config-if)#
Use one of the following commands to verify the configuration:
Command |
Purpose |
||||
---|---|---|---|---|---|
show class-map |
Displays the class maps defined on the switch. |
||||
show policy-map [name] |
Displays the policy maps defined on the switch. Optionally, you can display the named policy only. |
||||
show policy-map interface [interface number] |
Displays the policy map settings for an interface or all interfaces. |
||||
show queuing interface [interface slot/\port] |
Displays the queue configuration and statistics.
|
||||
show interface flowcontrol [module numbef ] |
Displays the detailed listing of the flow control settings on all interfaces. |
||||
show interface [interface slot/port] priority-flow-control [module number] |
Displays the priority flow control details for a specified interface.
|
||||
show interface untagged-cos [module number] |
Displays the untagged CoS values for all interfaces. |
||||
running-config ipqos |
Displays information about the running configuration for QoS. |
||||
startup-config ipqos |
Displays information about the startup configuration for QoS. |