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service-class wred ecn
Create a service class and assign ECN marking for different queues on backplane ports to the service class. This functionality
can be configured on the Z9000 platforms.
Syntax
[No] service-class wred ecn {backplane} queues-list
Parameters
service-class Define the mapping between the service class and policy-based QoS or routing
wred Associate WRED with ECN to mark packets instead of dropping them
ecn 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
backplane 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 9.6.0.0 Added support for backplane changes in the Z9000 platform.
Version 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. For Z9000, you can configure queues 0-3. For S6000, you can configure queues 0-7. By
default, ECN marking is disabled on all queues. When you enable wred-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-ecn, and the number of packets in the queue is between the minimum threshold and the
maximum threshold, one of the following two scenarios can occur:
● If the transmission endpoints are ECN-capable and traffic is congested, and the WRED algorithm
determines that the packet should have been 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.
When you enable wred-ecn, and the number of packets in the queue is above the maximum threshold,
packets are dropped based on the drop probability. This behavior is the identical treatment a packet
receives when WRED is enabled without ECN configured on the router.
Example
Dellconf) #service-class wred ecn backplane 0,3-5,7
service-pool wred
A global buffer pool that is a shared buffer pool accessed by multiple queues when the minimum guaranteed buffers for the
queue are consumed can be configured on the S6000 and Z9000 platforms.
Create a global buffer pool that is a shared buffer pool accessed by multiple queues when the minimum guaranteed buffers for
the queue are consumed. S4810, S4820T, S6000, and Z9000 platforms support four global service-pools in the egress direction.
Two service pools are used—one for lossy queues and the other for lossless (priority-based flow control (PFC)) queues. You
can enable WRED and ECN configuration on the global service-pools. You can define WRED profiles and weight on each of the
global service-pools for both lossy and lossless (PFC) service-pools.
Syntax
[No] service-pool wred {green | weight | yellow} {pool0 number/string|
pool1 number/string}
Parameters
service-pool Define the mapping between the service class and policy-based QoS or routing.
1276 Quality of Service (QoS)