# phpman > man > dcb-pfc(8)

[DCB-PFC(8)](https://www.chedong.com/phpMan.php/man/DCB-PFC/8/markdown)                                      Linux                                     [DCB-PFC(8)](https://www.chedong.com/phpMan.php/man/DCB-PFC/8/markdown)



## NAME
       dcb-pfc  - show / manipulate PFC (Priority-based Flow Control) settings of the DCB (Data Cen‐
       ter Bridging) subsystem

## SYNOPSIS
       **dcb** [ _OPTIONS_ ] **pfc** { _COMMAND_ | _help_ }


       **dcb** **pfc** **show** **dev** DEV [ **pfc-cap** ] [ **prio-pfc** ] [ **macsec-bypass** ] [ **delay** ] [ **requests** ] [ **in**‐‐
               **dications** ]

       **dcb** **pfc** **set** **dev** DEV [ **prio-pfc** _PFC-MAP_ ] [ **macsec-bypass** { **on** | **off** } ] [ **delay** _INTEGER_ ]

       _PFC-MAP_ := [ _PFC-MAP_ ] _PFC-MAPPING_

       _PFC-MAPPING_ := { _PRIO_ | **all** }**:**{ **on** | **off** }

       _PRIO_ := { **0** .. **7** }


## DESCRIPTION
       **dcb** **pfc** is used to configure Priority-based Flow Control attributes through Linux DCB (Data
       Center Bridging) interface. PFC permits marking flows with a certain priority as lossless,
       and holds related configuration, as well as PFC counters.


## PARAMETERS
       For read-write parameters, the following describes only the write direction, i.e. as used
       with the **set** command. For the **show** command, the parameter name is to be used as a simple key‐
       word without further arguments. This instructs the tool to show the value of a given parame‐
       ter. When no parameters are given, the tool shows the complete PFC configuration.


### pfc-cap
              A read-only property that shows the number of traffic classes that may simultaneously
              support PFC.


### requests
              A read-only count of the sent PFC frames per traffic class. Only shown when -s is
              given, or when requested explicitly.


### indications
              A read-only count of the received PFC frames per traffic class. Only shown when -s is
              given, or when requested explicitly.


       **macsec-bypass** { **on** | **off** }
              Whether the sending station is capable of bypassing MACsec processing when MACsec is
              disabled.


       **prio-pfc** _PFC-MAP_
              _PFC-MAP_ uses the array parameter syntax, see [**dcb**(8)](https://www.chedong.com/phpMan.php/man/dcb/8/markdown) for details. Keys are priorities,
              values are on / off indicators of whether PFC is enabled for a given priority.


       **delay** _INTEGER_
              The allowance made for round-trip propagation delay of the link in bits.  The value
              shall be 0..65535.


### EXAMPLE & USAGE
       Enable PFC on priorities 6 and 7, leaving the rest intact:


       # dcb pfc set dev eth0 prio-pfc 6:on 7:on

       Disable PFC of all priorities except 6 and 7, and configure delay to 4096 bits:


       # dcb pfc set dev eth0 prio-pfc all:off 6:on 7:on delay 0x1000

       Show what was set:


       # dcb pfc show dev eth0
       pfc-cap 8 macsec-bypass off delay 4096
       prio-pfc 0:off 1:off 2:off 3:off 4:off 5:off 6:on 7:on


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


## SEE ALSO
       [**dcb**(8)](https://www.chedong.com/phpMan.php/man/dcb/8/markdown)


## REPORTING BUGS
       Report any bugs to the Network Developers mailing list **<<netdev@vger.kernel.org>>** where the de‐
       velopment and maintenance is primarily done.  You do not have to be subscribed to the list to
       send a message there.


## AUTHOR
       Petr Machata <<me@pmachata.org>>



iproute2                                   31 October 2020                                [DCB-PFC(8)](https://www.chedong.com/phpMan.php/man/DCB-PFC/8/markdown)