HPE FlexFabric 5940 Switch Series
Intelligent Lossless Network Command Reference
Software version: Release 671x and later
Document version: 6W100-20230822
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Contents
PFC commands ····························································································· 1
display priority-flow-control ························································································································· 1
priority-flow-control (Ethernet interface view) ····························································································· 2
priority-flow-control (system view) ·············································································································· 3
priority-flow-control deadlock auto-recover action······················································································ 4
priority-flow-control deadlock auto-recover cos·························································································· 5
priority-flow-control deadlock cos ··············································································································· 6
priority-flow-control deadlock enable·········································································································· 7
priority-flow-control deadlock precision ······································································································ 7
priority-flow-control deadlock recover ········································································································ 8
priority-flow-control deadlock recover-mode ······························································································ 9
priority-flow-control deadlock threshold···································································································· 10
priority-flow-control deadlock threshold action ························································································· 11
priority-flow-control dot1p headroom ········································································································ 12
priority-flow-control dot1p ingress-buffer dynamic ··················································································· 13
priority-flow-control dot1p ingress-buffer static ························································································ 14
priority-flow-control dot1p ingress-threshold-offset ·················································································· 14
priority-flow-control dot1p reserved-buffer ······························································································· 15
priority-flow-control no-drop dot1p (Ethernet interface view) ··································································· 16
priority-flow-control no-drop dot1p (system view) ···················································································· 17
priority-flow-control headroom ·················································································································· 18
Document conventions and icons ································································ 20
Conventions ····················································································································································· 20
Network topology icons ···································································································································· 21
Support and other resources ······································································· 22
Accessing Hewlett Packard Enterprise Support······························································································· 22
Accessing updates ··········································································································································· 22
Websites ·················································································································································· 23
Customer self repair ································································································································· 23
Remote support ········································································································································ 23
Documentation feedback ························································································································· 23
Index ············································································································ 25
1
PFC commands
display priority-flow-control
Use display priority-flow-control to display the PFC information for an interface.
Syntax
display priority-flow-control interface [ interface-type
[ interface-number ] ]
Views
Any view
Predefined user roles
network-admin
network-operator
Parameters
interface-type: Specifies an interface type. If you do not specify an interface type, the
command displays the PFC information for all Ethernet interfaces.
interface-number: Specifies an interface number. If you do not specify an interface number, the
command displays the PFC information for all Ethernet interfaces of the specified type.
Examples
# Display the PFC information for all Ethernet interfaces.
<Sysname> display priority-flow-control interface
Conf -- Configured mode Ne -- Negotiated mode P -- Priority
Interface Conf Ne Dot1pList P Recv Sent
XGE1/0/1 Auto On 0,2-3,5-6 0 178 43
Table 1 Command output
Field
Description
Conf -- Configured mode Locally configured PFC status.
Ne -- Negotiated mode Negotiated PFC status.
P -- Priority 802.1p priority value for which PFC is enabled.
Interface Abbreviated name of the interface.
Conf
Locally configured PFC status:
• Auto—The interface is configured to autonegotiate the PFC status
with the remote end.
• Off—PFC is disabled for the interface.
• On—PFC is enabled for the interface.
Ne Negotiated PFC status:
• Off—PFC is disabled.
• On—PFC is enabled.
Dot1pList 802.1p priorities that are enabled with PFC. 802.1p priority values 0
through 7 are available.
2
Field
Description
P An 802.1p priority is displayed only when the 802.1p priority is enabled
with PFC and the interface has received or sent packets with the 802.1p
priority.
Recv Number of received PFC pause frames.
Sent Number of sent PFC pause frames.
Related commands
priority-flow-control
priority-flow-control no-drop dot1p
priority-flow-control (Ethernet interface view)
Use priority-flow-control to enable PFC on an Ethernet interface.
Use undo priority-flow-control to disable PFC.
Syntax
priority-flow-control { auto | enable }
undo priority-flow-control
Default
PFC is disabled on Ethernet interfaces.
Views
Ethernet interface view
Predefined user roles
network-admin
Parameters
auto: Specifies PFC in auto mode. In this mode, the local end automatically negotiates the PFC
status with the remote end.
enable: Forcibly enables PFC.
Usage guidelines
The local device notifies the remote end to stop sending packets carrying the specified 802.1p
priority if all of the following conditions exist:
•
Both the local end and the remote end have PFC enabled.
•
Both the local end and the remote end have the priority-flow-control no-drop
dot1p dot1p-list command configured.
•
The specified 802.1p priority is in the 802.1p priority list specified by the dot1p-list
argument.
•
The local end receives packets carrying the specified 802.1p priority, and the received packets
cause congestion.
When congestion is eliminated, the local end notifies the remote end to continue to send packets
carrying the specified 802.1p priority. In this way, the local device can forward packets carrying
802.1p priorities in the specified 802.1p priority list without packet drops.
If you execute this command in system view and Ethernet interface view multiple times, the most
recent configuration takes effect.
3
Examples
# Enable PFC on Ten-GigabitEthernet 1/0/1.
<Sysname> system-view
[Sysname] interface ten-gigabitethernet 1/0/1
[Sysname-Ten-GigabitEthernet1/0/1] priority-flow-control enable
Related commands
display priority-flow-control
priority-flow-control (system view)
priority-flow-control no-drop dot1p
priority-flow-control (system view)
Use priority-flow-control to enable PFC on all Ethernet interfaces.
Use undo priority-flow-control to disable PFC on all Ethernet interfaces.
Syntax
priority-flow-control { auto | enable }
undo priority-flow-control
Default
PFC is disabled on Ethernet interfaces.
Views
System view
Predefined user roles
network-admin
Parameters
auto: Specifies PFC in auto mode. In this mode, the local end automatically negotiates the PFC
status with the remote end.
enable: Forcibly enables PFC.
Usage guidelines
The local device notifies the remote end to stop sending packets carrying the specified 802.1p
priority if all of the following conditions exist:
•
Both the local end and the remote end have PFC enabled.
•
Both the local end and the remote end have the priority-flow-control no-drop
dot1p command configured.
•
The specified 802.1p priority is in the 802.1p priority list specified by the dot1p-list
argument.
•
The local end receives packets carrying the specified 802.1p priority, and the received packets
cause congestion.
When congestion is eliminated, the local end notifies the remote end to continue to send packets
carrying the specified 802.1p priority. In this way, the local device can forward packets carrying
802.1p priorities in the specified 802.1p priority list without packet drops.
If you execute this command in system view and Ethernet interface view multiple times, the most
recent configuration takes effect.
4
Examples
# Enable PFC on all Ethernet interfaces.
<Sysname> system-view
[Sysname] priority-flow-control enable
Related commands
display priority-flow-control
priority-flow-control (Ethernet interface view)
priority-flow-control no-drop dot1p
priority-flow-control deadlock auto-recover action
Use priority-flow-control deadlock auto-recover action to configure the action to
take on packets during the delay timer period for PFC deadlock detection automatic recovery.
Use undo priority-flow-control deadlock auto-recover action to restore the
default.
Syntax
priority-flow-control deadlock auto-recover action { discard |
forwarding }
undo priority-flow-control deadlock auto-recover action
Default
The device forwards the received data packets during the delay timer period for PFC deadlock
detection automatic recovery.
Views
System view
Predefined user roles
network-admin
Parameters
discard: Drops the received data packets.
forwarding: Forwards the received data packets.
Usage guidelines
When the device is in the PFC deadlock state, you cannot execute this command.
Examples
# Configure the device to drop received data packets during the delay timer period for PFC deadlock
detection automatic recovery.
<Sysname> system-view
[Sysname] priority-flow-control deadlock auto-recover action discard
Related commands
priority-flow-control deadlock cos
priority-flow-control deadlock enable
5
priority-flow-control deadlock auto-recover cos
Use priority-flow-control deadlock auto-recover cos to configure the delay timer
for PFC deadlock detection automatic recovery.
Use undo priority-flow-control deadlock auto-recover cos to delete the delay
timer for PFC deadlock detection automatic recovery.
Syntax
priority-flow-control deadlock auto-recover cos cos-value delay
delay-interval
undo priority-flow-control deadlock auto-recover cos [ cos-value ]
Default
The delay timer for PFC deadlock detection automatic recovery is not configured.
Views
System view
Predefined user roles
network-admin
Parameters
cos cos-value: Specifies the CoS value of packets, in the range of 0 to 7. Different CoS values
correspond to different 802.1p priority values. To see the CoS-to-802.1p mapping, execute the
display qos map-table dot1p-lp command.
delay delay-interval: Specifies the delay timer for PFC deadlock detection automatic
recovery, in the range of 1 to 15.
Usage guidelines
PFC deadlock detection periodically detects whether deadlock occurs to packets carrying the
specified CoS value. If the device enters the PFC deadlock state and PFC deadlock detection is
recovered in automatic mode, the device automatically recovers PFC deadlock detection after the
delay timer expires. The delay timer is 100 ms + delay-interval * 100 ms.
This command takes effect only in automatic recovery mode. When the device is in the PFC
deadlock state, you cannot execute this command.
The specified CoS value must be within the 802.1p priority values configured by using the
priority-flow-control no-drop dot1p command.
You can set the same delay timer for different CoS values.
If you execute this command multiple times for the same CoS value, the most recent configuration
takes effect.
Examples
# Set the delay timer for PFC deadlock detection automatic recovery to 5 for packets carrying CoS
value 7.
<Sysname> system-view
[Sysname] priority-flow-control deadlock auto-recover cos 7 delay 5
Related commands
display qos map-table dot1p-lp (ACL and QoS Command Reference)
priority-flow-control deadlock precision
priority-flow-control no-drop dot1p
6
priority-flow-control deadlock cos
Use priority-flow-control deadlock cos to set the PFC deadlock detection interval for
the specified CoS value.
Use undo priority-flow-control deadlock cos to delete the PFC deadlock detection
interval for the specified CoS value or all CoS values.
Syntax
priority-flow-control deadlock cos cos-value interval interval
undo priority-flow-control deadlock cos [ cos-value ]
Default
The PFC deadlock detection interval for a CoS value is not set.
Views
System view
Predefined user roles
network-admin
Parameters
cos cos-value: Specifies the CoS value of packets, in the range of 0 to 7.
interval interval: Specifies the PFC deadlock detection interval in the range of 1 to 15.
If you do not specify this keyword, the PFC feature and PFC deadlock detection feature are
automatically recovered on an interface when the detection interval expires, no matter whether the
interface receives PFC pause frames.
Usage guidelines
The PFC deadlock detection feature periodically detects whether deadlock occurs to packets that
carry the specified CoS value. To obtain the length of time for the detection interval, multiply the
detection interval by the precision of the PFC deadlock detection timer.
The PFC deadlock detection interval for a CoS value is the product of the interval argument
configured by using the priority-flow-control deadlock cos interval command and
the precision configured by using the priority-flow-control deadlock precision
command. For example, if you execute the priority-flow-control deadlock cos 5
interval 10 command to set the interval argument to 10 for CoS priority 5 and execute the
priority-flow-control deadlock precision command to set the precision to high
(which represents 10 milliseconds) for CoS priority 5, the PFC deadlock detection interval for CoS
priority 5 is 10*10 =100 milliseconds.
The specified CoS value must be within the 802.1p priority list specified by using the
priority-flow-control no-drop dot1p command. To view the 802.1p priority for each
CoS value, execute the display qos map-table dot1p-lp command.
You can set the same detection interval for different CoS values.
If you execute this command for the same CoS value multiple times, the most recent configuration
takes effect.
You cannot execute this command when the device is in PFC deadlock state.
Examples
# Set the PFC deadlock detection interval to 5 for packets carrying CoS value 7.
<Sysname> system-view
[Sysname] priority-flow-control deadlock cos 7 interval 5
7
Related commands
display qos map-table dot1p-lp (ACL and QoS Command Reference)
priority-flow-control deadlock precision
priority-flow-control no-drop dot1p
priority-flow-control deadlock enable
Use priority-flow-control deadlock enable to enable PFC deadlock detection on an
interface.
Use undo priority-flow-control deadlock enable to disable PFC deadlock detection
on an interface.
Syntax
priority-flow-control deadlock enable
undo priority-flow-control deadlock enable
Default
PFC deadlock detection is disabled on an interface.
Views
Ethernet interface view
Predefined user roles
network-admin
Usage guidelines
The device enters the PFC deadlock state if the following conditions exist on an interface:
•
PFC for 802.1p priorities is enabled by using the priority-flow-control and
priority-flow-control no-drop dot1p commands.
•
Packets carrying the specified 802.1p priority are transmitted in a loop.
•
No packets in the data buffer can be forwarded.
This command enables periodically detecting whether the device is in PFC deadlock state.
When the device is in the PFC deadlock state, you cannot execute this command.
Examples
# Enable PFC deadlock detection on Ten-GigabitEthernet 1/0/1.
<Sysname> system-view
[Sysname] interface ten-gigabitethernet 1/0/1
[Sysname-Ten-GigabitEthernet1/0/1] priority-flow-control deadlock enable
Related commands
priority-flow-control
priority-flow-control deadlock cos
priority-flow-control no-drop dot1p
priority-flow-control deadlock precision
Use priority-flow-control deadlock precision to set the precision for the PFC
deadlock detection timer.
8
Use undo priority-flow-control deadlock precision to restore the default.
Syntax
priority-flow-control deadlock precision { high | low | normal }
undo priority-flow-control deadlock precision
Default
The PFC deadlock detection timer uses normal precision.
Views
System view
Predefined user roles
network-admin
Parameters
high: Specifies the high precision for the PFC deadlock detection timer.
low: Specifies the low precision for the PFC deadlock detection timer.
normal: Specifies the normal precision for the PFC deadlock detection timer.
slot slot-number: Specifies an IRF member device by its member ID.
Usage guidelines
Use this command to adjust the precision for the PFC deadlock detection timer and change the PFC
deadlock detection interval. On this switch series, the high precision means 10 ms, and the normal
precision means 100 ms.
When the device is in the PFC deadlock state, you cannot execute this command.
If you execute this command multiple times, the most recent configuration takes effect.
Examples
# Set the high precision for the PFC deadlock detection timer.
<Sysname> system-view
[Sysname] priority-flow-control deadlock precision high
priority-flow-control deadlock recover
Use priority-flow-control deadlock recover to recover PFC deadlock detection on an
interface.
Syntax
priority-flow-control deadlock recover
Views
Ethernet interface view
Predefined user roles
network-admin
Usage guidelines
Before executing this command, first use the priority-flow-control deadlock
recover-mode command to configure the recovery mode for PFC deadlock detection.
The device can automatically release the deadlock state, but both the PFC deadlock detection and
PFC features are disabled on the interface at the same time. To manually recover PFC deadlock
9
detection on the interface, execute this command after setting the manual recovery mode for PFC
deadlock detection on the interface. The PFC feature is also enabled again when you execute this
command.
When the device is in the PFC deadlock state, you cannot execute this command.
Examples
# Recover PFC deadlock detection on Ten-GigabitEthernet 1/0/1.
<Sysname> system-view
[Sysname] interface ten-gigabitethernet 1/0/1
[Sysname-Ten-GigabitEthernet1/0/1] priority-flow-control deadlock recover
Related commands
priority-flow-control deadlock recover-mode
priority-flow-control deadlock recover-mode
Use priority-flow-control deadlock recover-mode to set the recovery mode for PFC
deadlock detection on an interface.
Use undo priority-flow-control deadlock recover-mode to restore the default.
Syntax
priority-flow-control deadlock recover-mode { auto | manual }
undo priority-flow-control deadlock recover-mode
Default
PFC deadlock detection recovers in automatic mode on an interface.
Views
Ethernet interface view
Predefined user roles
network-admin
Parameters
auto: Specifies the automatic recovery mode.
manual: Specifies the manual recovery mode.
Usage guidelines
When the PFC deadlock state is detected and PFC deadlock detection is recovered in automatic
mode, the device automatically releases the deadlock state and recovers PFC and PFC deadlock
detection after the delay timer expires. Within the delay timer period, the device disables PFC and
PFC deadlock detection on the interface, so that packets can be forwarded properly. PFC deadlock
detection can be recovered in automatic or manual mode on the interface. Recovering this feature
enables the PFC feature again at the same time. Use the automatic recovery mode when no serious
failures occur.
When a packet loop cannot be resolved and the device enters the PFC deadlock state frequently,
manually recover PFC deadlock detection on the interface as follows:
1. Perform troubleshooting and set the manual recovery mode for PFC deadlock detection.
2. Execute the priority-flow-control deadlock recover command to recover the
PFC deadlock detection and PFC features.
When the device is in the PFC deadlock state, you cannot execute this command.
10
Examples
# Set the manual recovery mode for PFC deadlock detection on Ten-GigabitEthernet 1/0/1.
<Sysname> system-view
[Sysname] interface ten-gigabitethernet 1/0/1
[Sysname-Ten-GigabitEthernet1/0/1] priority-flow-control deadlock recover-mode manual
Related commands
priority-flow-control deadlock recover
priority-flow-control deadlock threshold
Use priority-flow-control deadlock threshold to configure the upper threshold for
PFC deadlock times within the specified period.
Use undo priority-flow-control deadlock threshold to restore the default.
Syntax
priority-flow-control deadlock threshold cos cos-value period period
count count [ error-down ]
undo priority-flow-control deadlock threshold cos [ cos-value ]
Default
The upper threshold for PFC deadlock times within the specified period is not configured.
Views
System view
Predefined user roles
network-admin
Parameters
cos cos-value: Specifies the CoS value of packets, in the range of 0 to 7. Different CoS values
correspond to different 802.1p priority values. To see the CoS-to-802.1p mapping, execute the
display qos map-table dot1p-lp command.
period period: Specifies the period for detecting PFC deadlock times, in the range of 1 to 60
seconds.
count count: Specifies the upper threshold for PFC deadlock times within the specified period, in
the range of 1 to 500.
error-down: Shuts down an interface when the number of PFC deadlock times within the
detection period reaches the upper threshold. If you do not specify this keyword, PFC will be
disabled for the corresponding 802.1p priority when the number of PFC deadlock times within the
detection period reaches the upper threshold.
Usage guidelines
With this command executed, when the PFC deadlock times within the specified period exceed the
upper threshold on an interface, the device disables PFC for the corresponding 802.1p priority on the
interface. To recover the PFC feature on the interface in this case, execute the undo
priority-flow-control deadlock threshold command.
The detection period specified in this command must be longer than the PFC deadlock detection
interval configured by using the priority-flow-control deadlock cos command, so that
you can determine whether the device frequently enters the PFC deadlock state.
When the device is in the PFC deadlock state, you cannot execute this command.
11
The specified CoS value must be within the 802.1p priority values configured by using the
priority-flow-control no-drop dot1p command.
You can set the same detection period for different CoS values.
If you execute this command multiple times for the same CoS value, the most recent configuration
takes effect.
Examples
# Set the upper threshold for PFC deadlock times to 100 within the period of 5 seconds.
<Sysname> system-view
[Sysname] priority-flow-control deadlock threshold cos 7 period 5 count 100
Related commands
priority-flow-control deadlock cos
priority-flow-control deadlock threshold action
priority-flow-control no-drop dot1p
priority-flow-control deadlock threshold action
Use priority-flow-control deadlock threshold action to configure the action to take
on an interface when the number of PFC deadlock times within the specified detection period
exceeds the upper threshold.
Use undo priority-flow-control deadlock threshold action to restore the default.
Syntax
priority-flow-control deadlock threshold action { error-down | turn-off }
undo priority-flow-control deadlock threshold action
Default
The action specified by the priority-flow-control deadlock threshold command in
system view takes effect.
Views
Ethernet interface view
Predefined user roles
network-admin
Parameters
error-down: Shuts down an interface when the number of PFC deadlock times within the
specified detection period reaches the upper threshold and stops traffic forwarding on the interface.
turn-off: Disables PFC for the corresponding 802.1p priority when the number of PFC deadlock
times within the specified detection period reaches the upper threshold.
Usage guidelines
The threshold for PFC deadlock times and the detection period are configured by using the
priority-flow-control deadlock threshold command in system view. If the
priority-flow-control deadlock threshold action command is not executed on the
interface, the priority-flow-control deadlock threshold command in system view
takes effect. If the priority-flow-control deadlock threshold action command is
executed on the interface, this command takes effect.
12
If the priority-flow-control deadlock threshold command is not executed in system
view, the priority-flow-control deadlock threshold action command on the
interface does not take effect.
If the turn-off keyword is specified, the device disables PFC for the corresponding 802.1p priority
on the interface when the number of PFC deadlock times within the specified detection period
exceeds the upper threshold. To recover PFC on the interface in this case, first execute the undo
priority-flow-control enable command and then execute the
priority-flow-control enable command. Alternatively, you can execute the undo
priority-flow-control deadlock threshold command to recover PFC on an interface.
However, this command might affect the PFC state on multiple interfaces. Use this command as
needed.
If the error-down keyword is specified, the device shuts down the interface when the number of
PFC deadlock times within the specified detection period exceeds the upper threshold on the
interface. To bring up the interface and recover PFC on the interface in this case, execute the undo
shutdown command on the interface.
Examples
# Configure PFC to shut down the interface when the PFC deadlock times within the specified period
reaches the upper threshold.
<Sysname> system-view
[Sysname] interface gigabitethernet 1/0/1
[Sysname-GigabitEthernet1/0/1] priority-flow-control deadlock threshold action
error-down
Related commands
priority-flow-control deadlock threshold
priority-flow-control dot1p headroom
Use priority-flow-control dot1p headroom to set the headroom buffer threshold.
Use undo priority-flow-control dot1p headroom to restore the default.
Syntax
priority-flow-control dot1p dot1p headroom headroom-number
undo priority-flow-control dot1p dot1p headroom
Default
The headroom buffer threshold is 4000 for 40-GE interfaces and 1000 for 10-GE interfaces.
Views
Ethernet interface view
Predefined user roles
network-admin
Parameters
dot1p: Specifies an 802.1p priority in the range of 0 to 7.
headroom-number: Specifies the headroom buffer threshold. The value range is 1 to 4095.
Usage guidelines
Before executing this command, you must use the priority-flow-control no-drop dot1p
command to enable PFC for the specified 802.1p priority.
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If you execute this command multiple times for the same 802.1p priority, the most recent
configuration takes effect.
If you set the headroom buffer threshold when packets are being forwarded, traffic will be interrupted
and packets will be lost transiently.
Examples
# Set the headroom buffer threshold to 1000 for 802.1p priority 1 on Twenty-FiveGigE 1/0/1.
<sysname> system-view
[Sysname] interface twenty-fivegige 1/0/1
[Sysname-Twenty-FiveGigE1/0/1] priority-flow-control dot1p 1 headroom 1000
Related commands
priority-flow-control no-drop dot1p
priority-flow-control dot1p ingress-buffer dynamic
Use priority-flow-control dot1p ingress-buffer dynamic to set the dynamic back
pressure frame triggering threshold.
Use undo priority-flow-control dot1p ingress-buffer to restore the default.
Syntax
priority-flow-control dot1p dot1p ingress-buffer dynamic ratio
undo priority-flow-control dot1p dot1p ingress-buffer
Default
No dynamic back pressure frame triggering thresholds are set.
Views
Ethernet interface view
Predefined user roles
network-admin
Parameters
dot1p: Specifies an 802.1p priority in the range of 0 to 7.
ratio: Specifies the dynamic back pressure frame triggering threshold in percentage. The value
range for this argument is 1 to 100.
Usage guidelines
Before executing this command, you must use the priority-flow-control no-drop dot1p
command to enable PFC for the specified 802.1p priority.
If you execute this command multiple times for the same 802.1p priority, the most recent
configuration takes effect.
If you set the dynamic back pressure frame triggering threshold when packets are being forwarded,
traffic will be interrupted and packets will be lost transiently.
Examples
# Set the dynamic back pressure frame triggering threshold to 30 for 802.1p priority 1 on
Twenty-FiveGigE 1/0/1.
<sysname> system-view
[Sysname] interface twenty-fivegige 1/0/1
[Sysname-Twenty-FiveGigE1/0/1] priority-flow-control dot1p 1 ingress-buffer dynamic 30
14
Related commands
priority-flow-control no-drop dot1p
priority-flow-control dot1p ingress-buffer static
Use priority-flow-control dot1p ingress-buffer static to set the static back
pressure frame triggering threshold.
Use undo priority-flow-control dot1p ingress-buffer to restore the default.
Syntax
priority-flow-control dot1p dot1p ingress-buffer static threshold
undo priority-flow-control dot1p dot1p ingress-buffer
Default
The static back pressure frame triggering threshold is 1000 for 40-GE interfaces and 250 for 10-GE
interfaces.
Views
Ethernet interface view
Predefined user roles
network-admin
Parameters
dot1p: Specifies an 802.1p priority in the range of 0 to 7.
threshold: Specifies the static back pressure frame triggering threshold in the range of 1 to
79872.
Usage guidelines
Before executing this command, you must use the priority-flow-control no-drop dot1p
command to enable PFC for the specified 802.1p priority.
If you execute this command for the same 802.1p priority multiple times, the most recent
configuration takes effect.
Examples
# Set the static back pressure frame triggering threshold to 1000 for 802.1p priority 1 on
Twenty-FiveGigE 1/0/1.
<sysname> system-view
[Sysname] interface twenty-fivegige 1/0/1
[Sysname-Twenty-FiveGigE1/0/1] priority-flow-control dot1p 1 ingress-buffer static 1000
Related commands
priority-flow-control no-drop dot1p
priority-flow-control dot1p ingress-threshold-offset
Use priority-flow-control dot1p ingress-threshold-offset to set the offset
between the back pressure frame stopping threshold and triggering threshold.
Use undo priority-flow-control dot1p ingress-threshold-offset to restore the
default.
15
Syntax
priority-flow-control dot1p dot1p ingress-threshold-offset
offset-number
undo priority-flow-control dot1p dot1p ingress-threshold-offset
Default
The offset between the back pressure frame stopping threshold and triggering threshold is 204 for
40-GE interfaces and 51 for 10-GE interfaces.
Views
Ethernet interface view
Predefined user roles
network-admin
Parameters
dot1p: Specifies an 802.1p priority in the range of 0 to 7.
offset-number: Specifies the offset between the back pressure frame stopping threshold and
triggering threshold in the range of 1 to 79872.
Usage guidelines
Before executing this command, you must use the priority-flow-control no-drop dot1p
command to enable PFC for the specified 802.1p priority.
If you execute this command multiple times, the most recent configuration takes effect.
If you set the offset between the back pressure frame stopping threshold and triggering threshold
when packets are being forwarded, traffic will be interrupted and packets will be lost transiently.
Examples
# Set the offset between the back pressure frame stopping threshold and triggering threshold to
1000 for 802.1p priority 1 on Twenty-FiveGigE 1/0/1.
<sysname> system-view
[Sysname] interface twenty-fivegige 1/0/1
[Sysname-Twenty-FiveGigE1/0/1] priority-flow-control dot1p 1 ingress-threshold-offset
1000
Related commands
priority-flow-control no-drop dot1p
priority-flow-control dot1p reserved-buffer
Use priority-flow-control dot1p reserved-buffer to set the PFC reserved threshold.
Use undo priority-flow-control dot1p reserved-buffer to restore the default.
Syntax
priority-flow-control dot1p dot1p reserved-buffer reserved-number
undo priority-flow-control dot1p dot1p reserved-buffer
Default
The PFC reserved threshold is 15.
Views
Ethernet interface view
16
Predefined user roles
network-admin
Parameters
dot1p: Specifies an 802.1p priority in the range of 0 to 7.
reserved-number: Specifies the PFC reserved threshold in the range of 1 to 79872.
Usage guidelines
Before executing this command, you must use the priority-flow-control no-drop dot1p
command to enable PFC for the specified 802.1p priority.
If you execute this command multiple times for the same 802.1p priority, the most recent
configuration takes effect.
If you set the PFC reserved threshold when packets are being forwarded, traffic will be interrupted
and packets will be lost transiently.
Examples
# Set the PFC reserved threshold to 1000 for 802.1p priority 1 on Twenty-FiveGigE 1/0/1.
<sysname> system-view
[Sysname] interface twenty-fivegige 1/0/1
[Sysname-Twenty-FiveGigE1/0/1] priority-flow-control dot1p 1 reserved-buffer 1000
Related commands
priority-flow-control no-drop dot1p
priority-flow-control no-drop dot1p (Ethernet interface view)
Use priority-flow-control no-drop dot1p to enable PFC.
Use undo priority-flow-control no-drop dot1p to disable PFC for 802.1p priorities on
an Ethernet interface.
Syntax
priority-flow-control no-drop dot1p dot1p-list
undo priority-flow-control no-drop dot1p
Default
PFC is disabled for all 802.1p priorities on an Ethernet interface.
Views
Ethernet interface view
Predefined user roles
network-admin
Parameters
dot1p-list: Specifies an 802.1p priority (or dot1p priority) list to identify flows that are subject to
PFC (for example: 1,3-5). A hyphen (-) connects two numeric values, which together indicate a
continuous value range. Different values or value ranges are separated with commas (,). You can
configure up to 16 characters for this argument.
Usage guidelines
If you enable PFC and execute this command on both the local and peer devices, the local device
will notify the peer device to stop transmitting packets with the specified 802.1p priority when
congestion occurs. When congestion is removed, the local device notifies the peer device to
17
transmitting the packets again. This prevents packet loss for traffic with the specified priority. For
more information about 802.1p priority, see QoS configuration in ACL and QoS Configuration Guide.
This command is mutually exclusive with the flow-control command or the flow-control
receive enable command.
If you execute this command multiple times in system view and interface view, the most recent
configuration takes effect.
If you enable or disable PFC for the specified 802.1p priority when packets are being forwarded,
traffic will be interrupted, and transient packet loss will occur.
Examples
# Enable PFC in auto mode on Ten-GigabitEthernet 1/0/1, and enable PFC for 802.1p priority 5.
<Sysname> system-view
[Sysname] interface ten-gigabitethernet 1/0/1
[Sysname-Ten-GigabitEthernet1/0/1] priority-flow-control auto
[Sysname-Ten-GigabitEthernet1/0/1] priority-flow-control no-drop dot1p 5
Related commands
display priority-flow-control
flow-control (Interface Command Reference)
flow-control receive enable (Interface Command Reference)
priority-flow-control
priority-flow-control no-drop dot1p (system view)
priority-flow-control no-drop dot1p (system view)
Use priority-flow-control no-drop dot1p to enable PFC for 802.1p priorities on all
Ethernet interfaces.
Use undo priority-flow-control no-drop dot1p to disable PFC for 802.1p priorities on
all Ethernet interfaces.
Syntax
priority-flow-control no-drop dot1p dot1p-list
undo priority-flow-control no-drop dot1p
Default
PFC is disabled for all 802.1p priorities on all Ethernet interfaces.
Views
System view
Predefined user roles
network-admin
Parameters
dot1p-list: Specifies an 802.1p priority (or dot1p priority) list to identify flows that are subject to
PFC (for example: 1,3-5). A hyphen (-) connects two numeric values, which together indicate a
continuous value range. Different values or value ranges are separated with commas (,). You can
configure up to 16 characters for this argument.
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