# dcb

## NAME



           dcb - show / manipulate DCB (Data Center Bridging) settings
    


## SYNOPSIS



           **dcb**[ _OPTIONS_ ] { **app** | **buffer** | **ets** | **maxrate** | **pfc**} { _COMMAND_ |
                   _help_ }
    
           **dcb**[ **-force**] **-batch** _filename_
    
           **dcb**[ _OPTIONS_ ] **help**
    


## OPTIONS



           **-n** , **--netns** <NETNS>
                  switches **dcb** to the specified network namespace _NETNS_.
    
           **-V** , **--Version**
                  Print the version of the **dcb** utility and exit.
    
           **-b** , **--batch** <FILENAME>
                  Read commands from provided file or standard input and
                  invoke them. First failure will cause termination of dcb.
    
           **-f** , **--force**
                  Don't terminate dcb on errors in batch mode. If there were
                  any errors during execution of the commands, the
                  application return code will be non zero.
    
           **-i** , **--iec**
                  When showing rates, use ISO/IEC 1024-based prefixes (Ki,
                  Mi, Bi) instead of the 1000-based ones (K, M, B).
    
           **-j** , **--json**
                  Generate JSON output.
    
           **-N** , **--Numeric**
                  If the subtool in question translates numbers to symbolic
                  names in some way, suppress this translation.
    
           **-p** , **--pretty**
                  When combined with -j generate a pretty JSON output.
    
           **-s** , **--statistics**
                  If the object in question contains any statistical
                  counters, shown them as part of the "show" output.
    


## OBJECTS



           **app** - Configuration of application priority table
    
           **buffer** - Configuration of port buffers
    
           **ets** - Configuration of ETS (Enhanced Transmission Selection)
    
           **maxrate**
                  - Configuration of per-TC maximum transmit rate
    
           **pfc** - Configuration of PFC (Priority-based Flow Control)
    


## COMMANDS



           A _COMMAND_ specifies the action to perform on the object. The set
           of possible actions depends on the object type. As a rule, it is
           possible to **show** objects and to invoke topical **help,** which prints
           a list of available commands and argument syntax conventions.
    


## ARRAY PARAMETERS



           Like commands, specification of parameters is in the domain of
           individual objects (and their commands) as well. However, much of
           the DCB interface revolves around arrays of fixed size that
           specify one value per some key, such as per traffic class or per
           priority. There is therefore a single syntax for adjusting
           elements of these arrays. It consists of a series of _KEY_**:**_VALUE_
           pairs, where the meaning of the individual keys and values depends
           on the parameter.
    
           The elements are evaluated in order from left to right, and the
           latter ones override the earlier ones. The elements that are not
           specified on the command line are queried from the kernel and
           their current value is retained.
    
           As an example, take a made-up parameter tc-juju, which can be set
           to charm traffic in a given TC with either good luck or bad luck.
           _KEY_ can therefore be 0..7 (as is usual for TC numbers in DCB), and
           _VALUE_ either of **none** , **good** , and **bad**. An example of changing a juju
           value of TCs 0 and 7, while leaving all other intact, would then
           be:
    
           # dcb foo set dev eth0 tc-juju 0:good 7:bad
    
           A special key, **all** , is recognized which sets the same value to all
           array elements. This can be combined with the usual single-element
           syntax. E.g. in the following, the juju of all keys is set to
           **none** , except 0 and 7, which have other values:
    
           # dcb foo set dev eth0 tc-juju all:none 0:good 7:bad
    


## EXIT STATUS



           Exit status is 0 if command was successful or a positive integer
           upon failure.
    


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