Administrator Guide

Data Center Technology Commands 1158
CoS queue configuration. The TCG scheduling and bandwidth enforcement
occurs after the CoS queue scheduling and bandwidth enforcement is
performed. Therefore all CoS queues mapped to the same TCG share the
scheduling and bandwidth properties of the TCG.
ETS Operations
ETS provides an operational model for priority processing and bandwidth
allocation for the switch in a Data Center Bridging environment. Using
priority-based processing and bandwidth allocations, different Traffic Class
Groups (TCGs) within different types of traffic such as LAN, SAN and
Management can be configured to provide bandwidth allocation or best effort
transmit characteristics.
For ETS to be operational, the following configuration steps need to be
performed:
1 Configure CoS queues to Traffic Class Group mapping for the egress
ports.
2 Configure weight percentage (bandwidth allocation) for each TCG.
3 Enable appropriate scheduling algorithm for each TCG
CoS information is exchanged with peer DCBX devices using ETS TLVs. As
part of the transmitted ETS TLVs, by default, DCBX advertises the following
parameters, and these parameters are populated in the switch hardware on a
per port basis.
1 Mapping between ingress ports 802.1p priority to Traffic Class Group
(TCG).
2 Bandwidth percentage (weight percentage) of each Traffic Class Group.
3 Scheduling algorithm for each Traffic Class Group.
For Dell EMC Networking switches which do not support configuration of
ETS traffic classes in the hardware, the ETS information is propagated from
the configuration source to the other DCBX peers.
The mapping between the ingress port’s 802.1p priority and TCG is not
direct. The mapping depends upon:
• The CoS map defining the CoS queue that a packet is egress forwarded for
the ingress 802.1p priority.
• Traffic Class Group map defining the CoS queue to TCG mapping.