DELL N3000 User Manual

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Configuring Data Center Bridging Features
Traffic is passed across stacking links using WDRR for all CoS queues. This 
will affect the observed behavior of ETS on egress ports scheduling traffic 
from over-subscribed stacking links.
The three supported traffic class groups support an industry standard 
configuration such that one traffic class group offers lossless service (PFC 
enabled using WRR); one traffic class group contains priorities which are best 
effort (PFC disabled using WRR); and one traffic class group offers an 
expedited service (utilizes strict priority). When auto configuration is 
enabled on ports using ETS, the traffic classes are combined according to the 
above. Internally, the DCBX TCG mapping is restricted to using three TCGs 
regardless of the number of TCGs advertised by the configuration source, 
with the strict priority traffic mapped onto TCG 2, lossless traffic mapped 
onto TCG1, and all other traffic mapped onto TCG0.
For ETS to be operational in a manually configured environment, the 
following minimum steps must be performed:
Configure the CoS queue to Traffic Class Group mapping for the egress 
ports. 
Enable the appropriate scheduling algorithm for each TCG. 
Configure the weight percentage for each TCG.
Variation on the Example Configuration
This example configures three classes of traffic and utilizes the secondary 
(ETS) scheduler only:
• Best effort traffic: CoS Queue 0 for untagged and VLAN tagged frames 
with VPTs: 0, 1, and 2
• Lossless iSCSI: CoS Queue 1, VLAN tagged frames with VPT equal to 3
• Expedited Traffic: CoS Queue 2, VLAN tagged frames with VPTs: 4, 5, 6, 7
console(config-if-Te1/0/2)#classofservice dot1p-mapping 0 0
console(config-if-Te1/0/2)#classofservice dot1p-mapping 1 0
console(config-if-Te1/0/2)#classofservice dot1p-mapping 2 0
console(config-if-Te1/0/2)#classofservice dot1p-mapping 3 1
console(config-if-Te1/0/2)#classofservice dot1p-mapping 4 2
console(config-if-Te1/0/2)#classofservice dot1p-mapping 5 2
console(config-if-Te1/0/2)#classofservice dot1p-mapping 6 2
console(config-if-Te1/0/2)#classofservice dot1p-mapping 7 2
console(config-if-Te1/0/1)#classofservice traffic-class-group 0 0
console(config-if-Te1/0/1)#classofservice traffic-class-group 1 1