Users Guide

Data Center Technology Commands 1190
For a given Traffic Class, a value specified in Interface Configuration mode
only affects a single interface, whereas a change in Global Configuration
mode is applied to all interfaces. The Interface Configuration mode
command is only available on platforms that support independent per-port
class of service mappings. Ports that are configured to use the DCBX auto-
configuration roles (auto-up or auto-down) have their ETS settings
overridden. Only ports configured as DCBX manual role utilize the
configured ETS settings.
It is recommended that all strict priority traffic classes be mapped to a single
TCG.
Internally, frames are selected for transmission from the strict priority TCGs
first, then, once the constraints of the TCGs are satisfied, frames from the
WRR TCGs are selected for transmission. For example, grouping strict
priority assignments into TCG 1 and weighted assignments into TCG 0 will
result in all frames of the highest priority in TCG 1 being transmitted first,
then the next lower priority, et. seq. until no frames remain for transmission
in TCG 1. Then the scheduler will process frames from TCG 0, giving them
appropriate treatment based upon the weights, minimum bandwidth and
maximum bandwidth constraints.
Traffic class group 7 is reserved by the system for internal use.
Example
The following example demonstrates how to globally map priorities 1 and 2 to
TCG 1.
console(config)# classofservice traffic-class-group 1 1
console(config)# classofservice traffic-class-group 2 1
traffic-class-group max-bandwidth
Use this command in Global Config or Interface Configuration mode to
specify the maximum transmission bandwidth limit for each TCG as a
percentage of the interface rate. Also known as rate shaping, this has the
effect of smoothing temporary traffic bursts over time so that the transmitted
traffic rate is bound.
Syntax
traffic-class-group max-bandwidth bw-0 bw-1 … bw-n