Dell PowerEdge M420 Configuration Manual page 712

so PFC is enabled on these ports with 802.1p priority 5 traffic as no-drop. The
configuration also enables VLAN tagging so that the 802.1p priority is
identified. This example assumes the voice VLAN (VLAN 100) has already
been configured.
CAUTION:
(FC) or PFC settings. PFC uses a control packet defined in 802.1Qbb and is not
compatible with 802.3x FC.
1 Map 802.1p priority 5 to traffic class 4. For more information about traffic
classes, see "Configuring Class-of-Service" on page 1127.
console#configure
console(config)#classofservice dot1p-mapping 5 4
2 Enter Interface Configuration mode for ports 3, 5, and 10, and then enter
Data Center Bridging mode for these ports.
console(config)#interface range
te1/0/3,te1/0/5,te1/0/10
console(config-if)#datacenter-bridging
3 Enable PFC and configure traffic marked with 802.1p priority 5 to be
paused rather than dropped when congestion occurs.
console(config-dcb)#priority-flow-control mode on
console(config-dcb)#priority-flow-control
priority 5 no-drop
console(config-dcb)#exit
4 Enable VLAN tagging on the ports so the 802.1p priority is identified.
console(config-if)#switchport mode general
console(config-if)#switchport general allowed vlan
add 100 tagged
console(config-if)#exit
712
Configuring Port-Based Traffic Control
All ports may be briefly shutdown when modifying either flow control