DELL 8132 ユーザーズマニュアル

Data Center Bridging Commands

For a given Traffic Class, a value specified in Interface Config mode only 

affects a single interface, whereas a change in Global Config mode is applied 

to all interfaces. The Interface Config 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.

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

Use this command in Global Config or Interface Config 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.

2CSPC4.X8100-SWUM102.book  Page 890  Friday, March 15, 2013  8:56 AM