Priority-based Flow Control Commands
This section lists and describes the commands that can be used to configure Priority-based Flow Control (PFC) in a Data Center Bridging (DCB) environment.It includes the following commands:
• monitor pfc
monitor ecn
Use this command to enable Explicit-Congestion-Notification (ECN) marked packets monitoring on a physical interface.
Use the no form of this command to disable ECN monitoring on the interface
Command Syntax
monitor ecn
no monitor ecn
Parameters
None
Default
None
Command Mode
Interface mode
Applicability
This command was introduced beforeOcNOS version 7.0.0
Example
#configure terminal (config)
(config)#interface xe1
(config-if)#monitor ecn
monitor pfc
Use this command to enable Priority-based Flow Control (PFC) pause frames monitoring on a physical interface.
Use the no form of this command to disable PFC monitoring on the interface.
Command Syntax
monitor pfc
no monitor pfc
Parameters
None
Default
None
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 7.0.0
Example
#configure terminal
(config)#interface xe1
(config-if)#monitor pfc
priority-flow-control accept-peer-config
Use this command to enable willing mode for PFC on the interface.
If willing is enabled, then by default advertise mode is also enabled.
Use the no form of this command to disable willing mode.
Command Syntax
priority-flow-control accept-peer-config
no priority-flow-control accept-peer-config
Parameters
None
Default
By default, willing mode for PFC on the interface is disabled. If willing is enabled, then by default advertise mode is also enabled.
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Examples
#configure terminal
(config)#interface xe1
(config-if)#priority-flow-control accept-peer-config
priority-flow-control advertise-local-config
Use this command to enable advertising mode for PFC on the interface.
Use the no form of this command to disable advertising mode.
Command Syntax
priority-flow-control advertise-local-config
no priority-flow-control advertise-local-config
Parameters
None
Default
By default, advertising mode for PFC on the interface is disabled. If willing is enabled, then by default advertise mode is also enabled.
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Examples
#configure terminal
(config)#interface xe1
(config-if)#priority-flow-control advertise-local-config
priority-flow-control enable
Use this command to enable Priority-based Flow Control (PFC) on a switch (bridge).
Use the no form of this command to disable PFC.
Command Syntax
priority-flow-control enable bridge <1-32>
no priority-flow-control bridge <1-32>
Parameters
<1-32>
Bridge ID.
Default
By default, PFC is disabled.
Command Mode
Configure mode
Default
PFC is disabled by default.
Applicability
This command was introduced before OcNOS version 1.3. This command is applicable for L3 interface from OcNOS version 6.6.1
Example
#configure terminal
(config)#priority-flow-control enable bridge 32
#configure terminal
(config)#no priority-flow-control bridge 32
priority-flow-control cap
Use this command to configure a priority-flow-control cap for the number of priorities allowed on an interface.
Use the no parameter along with this command to return the value to its default level.
Command Syntax
priority-flow-control cap <0-8>
no priority-flow-control cap
Parameters
<0-8>
Select a cap value. Zero indicates that there is no limitations.
Default
By default, priority-flow-control cap value is 8.
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Examples
#configure terminal
(config)#interface xe2
(config-if)#priority-flow-control cap 7
priority-flow-control enable priority
Use this command to enable the PFC at the interface level for a specific priority.
Use the no parameter along with this command to disable PFC for a priority.
Command Syntax
priority-flow-control enable priority <0-7> (<0-7>(<0-7>(<0-7> (<0-7>(<0-7>(<0-7>(<0-7>|)|)|)|)|)|)|)
no priority-flow-control enable priority <0-7> (<0-7>(<0-7>(<0-7>(<0-7>(<0-7>(<0-7>(<0-7>|)|)|)|)|)|)|)
Parameter
<0-7>
Traffic-priority value. You can specify up to seven priorities.
Default
None
Command Mode
Interface mode
Default
PFC is disabled by default.
Applicability
This command was introduced before OcNOS version 1.3.
Examples
(config)#interface xe1
(config-if)#priority-flow-control enable priority 1 2 3 4 5 6 7
(config)#interface xe1
(config-if)#no priority-flow-control enable priority 2 3 4
priority-flow-control link-delay-allowance
Use this command to set PFC link delay allowance on an interface. This command provides allowance for round-trip propagation delay of the link in bits; moreover, it is one of the factors that determines when to trigger PAUSE.
Use the no parameter along with this command to unset PFC link delay allowance on an interface.
Command Syntax
priority-flow-control link-delay-allowance <0-4294967296>
no priority-flow-control link-delay-allowance
Parameter
<0-4294967296>
Link characteristics that affect the link delay (for example, link length).
Note: The range value is determined by the board type: for Tomahawk 3, it is 8,388,608; for Trident 3, it is 4,194,304; and for all other boards, the default value is 524,288.
Command Mode
Interface mode
Default
Default value is zero.
Applicability
This command was introduced before OcNOS version 1.3.
Example
#configure terminal
(config)#interface xe1
(config-if)#priority-flow-control link-delay-allowance 5
(config)#interface xe1
(config-if)#no priority-flow-control link-delay-allowance
priority-flow-control mode
Use this command to enable Priority-based Flow Control (PFC) on an interface.
Ues the no form of this command to disable PFC on an interface.
Command Syntax
priority-flow-control mode (on | auto)
no priority-flow-control
Parameters
auto
Negotiate PFC capabilities.
on
Force-enable PFC, overriding negotiation.
Default
By default, PFC is disabled.
Command Mode
Interface mode
Default
PFC is disabled by default.
Applicability
This command was introduced before OcNOS version 1.3. This command is applicable for L3 interface from OcNOS version 6.6.1
Example
#configure terminal
(config)#interface xe1
(config-if)#priority-flow-control mode auto
clear priority-flow-control deadlock-status
Use this command to clear the PFC deadlock details for a specified interface or for all interfaces
Command Syntax
clear priority-flow-control deadlock-status [ IFNAME ]
Parameters
IFNAME
Name of the input or output interface.
Default
None
Command Mode
Exec mode
Applicability
This command was introduced before OcNOS version 7.0.0.
Example
#clear priority-flow-control deadlock-status interface eth1
priority-flow-control deadlock manual-recovery
Use this command to start/stop manually the PFC deadlock recovery on the specified interface.
Command Syntax
priority-flow-control <NAME> deadlock manual-recovery ( start | stop
Parameters
IFNAME
Name of the input or output interface.
Default
Nones
Command Mode
Exec mode
Applicability
This command was introduced before OcNOS version 7.0.0.
Example
#priority-flow-control eth1 deadlock manual-recovery start
#priority-flow-control eth1 deadlock manual-recovery stop
priority-flow-control deadlock recovery-action drop
Use this command to globally drop deadlocked traffic on Priority-based Flow Control (PFC) deadlock recovery.
Use the no form of this command to allow deadlocked traffic when a PFC deadlock recovery occurs.
Command Syntax
priority-flow-control deadlock recovery-action drop
no priority-flow-control deadlock recovery-action drop
Parameters
None
Default
By default, PFC deadlocked traffic during a recovery is allowed.
Command Mode
Configuration mode
Applicability
This command was introduced before OcNOS version 7.0.0.
Example
#configure terminal (config)
#priority-flow-control deadlock recovery-action drop
priority-flow-control deadlock recovery-mode timer
Use this command to enable Priority-based Flow Control (PFC) deadlock and recovery on all priorities of an interface, using a timer to end the recovery phase.
Use the no form of this command to disable PFC deadlock detection and recovery on an interface.
Command Syntax
priority-flow-control deadlock recovery-mode timer [ detection-multiplier <1-1599> time-granularity <1|10|100> ] [ recovery-time <100-1599> ]
no priority-flow-control deadlock recovery-mode
Parameters
detection-multiplier
Specify the detection multiplier duration in micro seconds.
time-granularity
Specify the time granularity duration in micro seconds.
recovery-time
Specify the Recovery time duration in micro seconds.
Default
By default, detection multiplier is 10, time granularity is 10ms and recovery time is 100ms.
PFC deadlock detection is disabled by default.
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 7.0.0.
Example
#configure terminal (config)
(config)#interface xe1
(config-if)#priority-flow-control deadlock recovery-mode timer detection-multiplier 100 time-granularity 100 recovery-time 1000
OcNOS(config)#interface xe0
OcNOS(config-if)#no priority-flow-control deadlock recovery-mode
priority-flow-control deadlock recovery-mode pfc-state-xon
Use this command to enable Priority-based Flow Control (PFC) deadlock and recovery on all priorities of an interface, using XON packet reception end the recovery phase.
Use this command to enable Priority-based Flow Control (PFC) deadlock and recovery on all priorities of an interface to cause any XON packet received in the interface to end the recovery phase.
Use the no form of this command to disable PFC deadlock detection and recovery on an interface.
Command Syntax
priority-flow-control deadlock recovery-mode pfc-state-xon [ detection-multiplier <1-1599> time-granularity <1|10|100> ]
no priority-flow-control deadlock recovery-mode
Parameters
detection-multiplier
Specify the detection multiplier duration in micro seconds.
time-granularit
y
Specify the time granularity duration in micro seconds.
Default
By default, detection multiplier is 10, and time granularity is 10ms.
PFC deadlock detection is disabled by default.
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 7.0.0.
Example
#configure terminal (config)
(config)#interface xe1
(config-if)#priority-flow-control deadlock recovery-mode pfc-state-xon detection-multiplier 100 time-granularity 100
show priority-flow-control deadlock-status
Use this command to display the PFC deadlock details for a specified interface or for all interfaces.
Command Syntax
show priority-flow-control deadlock-status [ IFNAME ]
Parameters
IFNAME
Name of the input or output interface.
Default
None
Command Mode
Exec mode
Applicability
This command was introduced before OcNOS version 7.0.0.
Example
#show priority-flow-control deadlock-status
Deadlock Detection and Recovery Configuration
----------------------------------------------------------------------
interface recovery detection detection recovery
mode multiplier granularity time
======================================================================
xe0 Timer 10 10 1500
---------------------------------------------------------------------------------------------------
Deadlock Detection and Recovery Status
---------------------------------------------------------------------------------------------------------
interface pri state detection last detection last recovery
count timestamp timestamp
===================================================================================================
xe0 1 deadlock 39 2025-05-29 19:03:49.481 -
show priority-flow-control details
Use this command to display the PFC details for a specified interface.
Command Syntax
show priority-flow-control details ((all|interface IFNAME)|(bridge <1-32>))
Parameters
IFNAME
Name of the input or output interface.
<1-32>
Specify a bridge ID.
all
Display PFC enabled L2 and L3 interfaces
Default
None
Command Mode
Exec mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#show priority-flow-control details interface xe1
bridge : 2
priority flow control : on
interface : xe1
Admin Configuration
mode advertise willing cap link priorities
delay
allowance
================================================================================
on on off 5 128 2 3 4 5
Operational Configuration
state cap link priorities
delay
allowance
================================================================================
on 5 128 2 3 4 5
Table 1-1: Show priority-flow control details output
Entry | Description |
|---|
bridge | The bridge number to which this interface is associated (1-32). |
priority flow control | Show whether priority flow control is either on or off. |
interface | The interface name. |
Admin Configuration | The configuration as entered on this device. |
mode | The priority flow control operating mode – on, off, or auto. |
advertise | Status of advertisement of the configuration to the peer device. |
willing | The willingness of the local interface to learn the PFC configuration from the peer. Values are either on or off. |
cap | Cap is a limit set that specifies the maximum number of PFC priorities. |
link delay allowance | The allowance made for round-trip propagation delay of the link in bits. |
Priorities | Shows the PFCs that have been to be used on the priorities. |
Operational Configuration | The actual configuration that exists between this device and its PFC peer. |
state | Shows whether PFC is functioning. Values are on, off, or auto. |
cap | Cap is the limit that specifies the maximum number of PFC priorities. |
link delay allowance | The allowance being used for round-trip propagation delay of the link in bits. |
priorities | The PFCs actually being used by this device and its peer. |
show priority-flow-control statistics
Use this command to display statistics about the number of PFC Pause frames sent and received for a specified interface or bridge. If you do not specify a bridge or interface, this commands shows statistics for the bridge.
Command Syntax
show priority-flow-control statistics ((all|interface IFNAME)| (bridge <1-32>))
Parameters
<1-32>
Specify bridge ID.
IFNAME
Name of the input or output interface.
all
Display PFC enabled L2 and L3 interfaces
Default
None
Command Mode
Exec mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#show priority-flow-control statistics interface xe1
bridge : 2
interface : xe1
pause sent pause received
==============================
59680614996248372055834574861