Dell C1048P Port Extender Networking Command-Line Reference Guide for the C900 - Page 1500

service-class wred ecn backplane Apply ECN marking on backplane port-queues in a service class. C9000 Series Syntax Parameters [no] service-class wred ecn queue-list backplane service-class wred ecn queue-list backplane Define the mapping between the service class and policy-based QoS or routing. Associate WRED with ECN to mark packets instead of dropping them. Cause explicit congestion notification (ECN) to be used to indicate network congestion, rather than dropping packets, queues-list Enter the queue numbers, either as individual queue numbers separated by commas or as an inclusive list separating the starting and ending queue numbers with a hyphen Enter the port-queue numbers, either as individual queue numbers separated by commas or as an inclusive list separating the starting and ending queue numbers with a hyphen; for example, service-class wred ecn 0, 2, 4-6 backplane. The range of queue IDs is 0 to 7. Specify that the ECN marking configured for each queue applies to backplane ports. Default By default, ECN marking is disabled on all queues. Command Modes CONFIGURATION mode Command History Version Description 9.9(0.0) Introduced on the C9010. 9.3.0.0 Introduced on the Z9500 switch. 9.3.0.0 Introduced on the Z9000 platform. Usage Information You can add or remove ECN marking configuration on a list of queues on all backplane ports. All of the configured attributes apply to all the backplane ports and are for each queue. You can configure all the data queues. You can configure queues 0 to 7. By default, ECN marking is disabled on all queues. When you enable WRED with ECN and the number of packets in the queue is below the minimum threshold, packets are transmitted per the usual WRED treatment. When you enable WRED with ECN and the number of packets in the queue is between the minimum threshold and the maximum threshold, one of the following three scenarios can occur: • If the transmission endpoints are ECN-capable and traffic is congested, and the WRED algorithm determines that the packet should be dropped based on the drop probability, the packet is transmitted and marked so the routers know the system is congested and can slow transmission rates. • If neither endpoint is ECN-capable, the packet may be dropped based on the WRED drop probability. This behavior is the identical treatment that a packet receives when WRED is enabled without ECN configured on the router. • If the network is experiencing congestion, the packet is transmitted. No further marking is required. When you enable WRED with ECN and the number of packets in the queue is above the maximum Quality of Service (QoS) 1500