D-Link DGS-1520 Emulator - Page 961

DGS-1520 Series Gigabit Ethernet Smart Managed Switch CLI Reference Guide Command Default Level Level: 12. Usage Guideline Ethernet interfaces use Priority-based Flow Control (PFC) to provide lossless service. PFC, which is defined in IEEE 802.1Qbb, extends the basic IEEE 802.3x PAUSE semantics and uses the IEEE 802.1p CoS values in the IEEE 802.1Q VLAN tag to differentiate up to eight CoSs that can be subject to flow control independently. If PFC of all priorities is disabled, the interface defaults to the IEEE 802.3x flow control setting. When PFC of any priority is enabled, the interface will recognize PFC PAUSE frames. In other words, the Switch will pause a CoS on which PFC is enabled and the received PFC PAUSE indicates the CoS should be paused. A PFC PAUSE frame will be transmitted if the congestion is detected on the PFC enabled CoS. To enable PFC on a per-CoS basis, do the following: • Use the class-map type network-qos match-any global configuration command to create a type network QoS class map. o Use the match cos class-map configuration command to specify which CoS to configure. • Use the policy-map type network-qos command to create a type network QoS policy map. o Use the class type network-qos policy-map configuration command to specify a type network QoS class map to be associated with a traffic policy and then enter into the policy-map type network-QoS class configuration mode. o Use the pause policy map type network-qos class configuration command to enable PFC pause characteristics on a class referenced in a type network QoS policy map. • Use the service-policy type network-qos input interface configuration command to apply a type network QoS policy map. Example This example shows how to enable PFC on priority 3 and 4 on port 3. Step 1: Create a type network QoS class map, named "my_class_map" and set the criteria to match CoS 3 or 4. Switch#configure terminal Switch(config)#class-map type network-qos match-any my_class_map Switch(config-cmap-nq)#match cos 3 Switch(config-cmap-nq)#match cos 4 Switch(config-cmap-nq)# Step 2: Create a type network QoS policy map, named "my_policy_map" and enable PFC for the class, "my_class_map", which is created in step 1. Switch#configure terminal Switch(config)#policy-map type network-qos my_policy_map Switch(config-pmap-nq)#class type network-qos my_class_map Switch(config-pmap-c-nq)#pause Switch(config-pmap-c-nq)#exit Switch(config-pmap-nq)# Step 3: Apply the type network QoS policy map, "my_policy_map", created in step 2, on port 3. Switch#configure terminal Switch(config)#interface eth1/0/3 Switch(config-if)#service-policy type network-qos input my_policy_map Switch(config-if)# 84-4 policy-map type network-qos This command is used to enter the Policy-map Configuration Mode to create or modify a type network QoS policy map that can be attached to one or more interfaces as a type network QoS service policy. 957