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

Configuring Link Level Flow Control
bandwidth percent 0
class type queuing c-out-q2
bandwidth percent 0
class type queuing c-out-q1
bandwidth percent 99
system qos
service-policy type queuing output my_queuing_policy
In the above example, c-out-q1 by default matches the traffic on qos-group 1. Therefore, the
non-default class-map for queuing which matches qos-group 1 is not needed. For further information
on configuring queuing, see
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
Configuring
network-qos.
Note
You must configure the no-drop class under system network-qos on the
Cisco Nexus 9200 and 9300-EX/FX platforms for releases earlier than
NX-OS 7.0(3)I7(3).
Device# configure terminal
Device(config)# interface ethernet 1/1
Device(config-if)# flowcontrol receive on
Device(config-if)# exit
system 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
Cisco Nexus 9000 Series NX-OS Quality of Service Configuration Guide, Release 7.x
Example: Configuring Link Level Flow Control Receive and Send
Queuing.
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