Example: Configuring Link Level Flow Control Receive And Send - Cisco Nexus 9000 Series Configuration Manual

Example: Configuring Link Level Flow Control Receive and Send

Classifying Traffic to a No-Drop Class
The following example shows how to create a QoS policy to map all the traffic to the no-drop class:
Device# configure terminal
Device(config)# class-map type qos class1
Device(config-cmap-qos)# match cos 2
Device(config-cmap-qos)# policy-map type qos my_qos_policy
Device(config-pmap-qos)# class type qos class1
Device(config-pmap-c-qos)# set qos-group 1
Device(config-pmap-c-qos)# interface e1/5
Device(config-sys-qos)# service-policy type qos input my_qos_policy
For LLFC to be enabled, you need to configure the no-drop policy on network-qos. The buffering module
needs to inform the MAC module to generate pause (either LLFC or PFC based on the interface level
configuration). PFC negotiation to the adapter is by using DCBX. LLFC or PFC is controlled by the
configuration on the interfaces. For example, the flow-control send and receive on enables LLFC on the
interfaces and the priority-flow-control mode on enables PFC on the interfaces.
If DCBX is supported, auto mode negotiates the PFC with the adapter. This is the interface level configuration
to enable LLFC or PFC but regardless of it, you have to configure network-qos level pause configuration for
LLFC to work. Even if the traffic is classified to qos-group 1 but when it generates pause, it generates LLFC
based on the interface level configuration.
Example: Configuring Link Level Flow Control Receive and Send
Configuring Link Level Flow Control Receive and Send
The following examples show how to configure Link Level Flow Control receive and send on the device:
• When only LLFC receive is enabled, no-drop class does not need to be configured on the system
• When both LLFC receive and send are enabled, no-drop class needs to be configured on the system
• When only LLFC send is enabled, no-drop class needs to be configured on the system network-qos.
Cisco Nexus 9000 Series NX-OS Quality of Service Configuration Guide, Release 7.x
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network-qos.
Device# configure terminal
Device(config)# interface ethernet 1/1
Device(config-if)# flowcontrol receive on
Device(config-if)# exit
network-qos. (Refer to the Configuring a No-Drop Policy example for information about configuring
the no-drop class.)
Device# configure terminal
Device(config)# interface ethernet 1/1
Device(config-if)# flowcontrol receive on
Device(config-if)# flowcontrol send on
Device(config-if)# exit
(Refer to the Configuring a No-Drop Policy example for information about configuring the no-drop
class.)
Device# configure terminal
Device(config)# interface ethernet 1/1
Device(config-if)# flowcontrol send on
Device(config-if)# exit
Configuring Link Level Flow Control