H3C S7500X Series User manual

H3C S7500X Switch Series
Interface Configuration Guide
New H3C Technologies Co., Ltd.
http://www.h3c.com
Software version: Release 7585P05 and later versions
Document version: 6W100-20200529

Copyright © 2020, New H3C Technologies Co., Ltd. and its licensors
All rights reserved
No part of this manual may be reproduced or transmitted in any form or by any means without prior written
consent of New H3C Technologies Co., Ltd.
Trademarks
Except for the trademarks of New H3C Technologies Co., Ltd., any trademarks that may be mentioned in this
document are the property of their respective owners.
Notice
The information in this document is subject to change without notice. All contents in this document, including
statements, information, and recommendations, are believed to be accurate, but they are presented without
warranty of any kind, express or implied. H3C shall not be liable for technical or editorial errors or omissions
contained herein.

Preface
This configuration guide covers the configuration of various interfaces.
This preface includes the following topics about the documentation:
•
Audience.
•
Conventions.
•
Documentation feedback.
Audience
This documentation is intended for:
•
Network planners.
•
Field technical support and servicing engineers.
•
Network administrators working with the S7500E switch series.
Conventions
The following information describes the conventions used in the documentation.
Command conventions
Convention
Description
Boldface Bold text represents commands and keywords that you enter literally as shown.
Italic Italic text represents arguments that you replace with actual values.
[ ] Square brackets enclose syntax choices (keywords or arguments) that are optional.
{ x | y | ... }
Braces enclose a set of required syntax choices separated by vertical bars, from which
you select one.
[ x | y | ... ]
Square brackets enclose a set of optional syntax choices separated by vertical bars,
from which you select one or none.
{ x | y | ... } *
Asterisk marked braces enclose a set of required syntax choices separated by vertical
bars, from which you select a minimum of one.
[ x | y | ... ] *
Asterisk marked square brackets enclose optional syntax choices separated by vertical
bars, from which you select one choice, multiple choices, or none.
&<1-n> The argument or keyword and argument combination before the ampersand (&) sign
can be entered 1 to n times.
# A line that starts with a pound (#) sign is comments.
GUI conventions
Convention
Description
Boldface Window names, button names, field names, and menu items are in Boldface. For
example, the New User window opens; click OK.
> Multi-level menus are separated by angle brackets. For example, File > Create >
Folder.

Symbols
Convention
Description
WARNING! An alert that calls attention to important information that if not understood or followed
can result in personal injury.
CAUTION:
An alert that calls attention to important information that if not understood or followed
can result in data loss, data corruption, or damage to hardware or software.
IMPORTANT:
An alert that calls attention to essential information.
NOTE:
An alert that contains additional or supplementary information.
TIP:
An alert that provides helpful information.
Network topology icons
Convention
Description
Represents a generic network device, such as a router, switch, or firewall.
Represents a routing-capable device, such as a router or Layer 3 switch.
Represents a generic switch, such as a Layer 2 or Layer 3 switch, or a router that
supports Layer 2 forwarding and other Layer 2 features.
Represents an access controller, a unified wired-WLAN module, or the access
controller engine on a unified wired-WLAN switch.
Represents an access point.
Represents a wireless terminator unit.
Represents a wireless terminator.
Represents a mesh access point.
Represents omnidirectional signals.
Represents directional signals.
Represents a security product, such as a firewall, UTM, multiservice security
gateway, or load balancing device.
Represents a security module, such as a firewall, load balancing, NetStream, SSL
VPN, IPS, or ACG module.
Examples provided in this document
Examples in this document might use devices that differ from your device in hardware model,
configuration, or software version. It is normal that the port numbers, sample output, screenshots,
and other information in the examples differ from what you have on your device.
T
T
T
T

Documentation feedback
You can e-mail your comments about product documentation to [e-mail].
We appreciate your comments.

i
Contents
Bulk configuring interfaces·············································································1
Configuration restrictions and guidelines···········································································································1
Configuration procedure·····································································································································1
Displaying and maintaining bulk interface configuration····················································································2

1
Bulk configuring interfaces
You can enter interface range view to bulk configure multiple interfaces with the same feature
instead of configuring them one by one. For example, you can execute the shutdown command in
interface range view to shut down a range of interfaces.
Configuration restrictions and guidelines
When you bulk configure interfaces in interface range view, follow these restrictions and guidelines:
•
In interface range view, only the commands supported by the first interface are available. The
first interface is specified with the interface range command.
•
Before you configure an interface as the first interface in an interface range, make sure you can
enter the view of the interface by using the interface interface-type { interface-number |
interface-number.subnumber } command.
•
Do not assign both an aggregate interface and any of its member interfaces to an interface
range. Some commands, after being executed on both an aggregate interface and its member
interfaces, can break up the aggregation.
•
No limit is set on the maximum number of interfaces in an interface range. The more interfaces
in an interface range, the longer the command execution time.
•
The maximum number of interface range names is limited only by the system resources. To
guarantee bulk interface configuration performance, configure fewer than 1000 interface range
names.
•
After a command is executed in interface range view, one of the following situations might
occur:
The system displays an error message and stays in interface range view. It means that the
execution failed on member interfaces in the interface range.
−If the execution failed on the first member interface in the interface range, the command
is not executed on any member interfaces.
−If the execution failed on non-first member interfaces, the command takes effect on the
other member interfaces.
The system returns to system view. It means that:
−The command is supported in both system view and interface view.
−The execution failed on a member interface in interface range view and succeeded in
system view.
−The command is not executed on the subsequent member interfaces.
You can use the display this command to verify the configuration in interface view of each
member interface. In addition, if the configuration in system view is not needed, use the
undo form of the command to remove the configuration.
Configuration procedure
Step Command Remarks
1. Enter system view. system-view N/A

2
Step Command Remarks
2. Enter interface range
view.
•interface range
{ interface-type
interface-number [ to
interface-type
interface-number ] } &<1-24>
•interface range name name
[ interface { interface-type
interface-number [ to
interface-type
interface-number ] }
&<1-24> ]
By using the interface range name
command, you assign a name to an
interface range and can specify this
name rather than the interface range
to enter the interface range view.
3. (Optional.) Display
commands available for
the first interface in the
interface range.
Enter a question mark (?) at the
interface range prompt. N/A
4. Use available
commands to configure
the interfaces. Available commands depend on
the interface. N/A
5. (Optional.) Verify the
configuration. display this N/A
Displaying and maintaining bulk interface
configuration
Execute the display command in any view.
Task Command
Display information about the interface ranges
created by using the interface range name
command. display interface range [name name ]

i
Contents
Configuring Ethernet interfaces ·····································································1
Configuring a management Ethernet interface ··································································································1
Ethernet interface naming conventions··············································································································2
Configuring common Ethernet interface settings·······························································································2
Configuring a combo interface (single combo interface)············································································2
Splitting a 40-GE interface and combining 10-GE breakout interfaces······················································3
Changing the interface type of 100-GE interfaces in batches····································································4
Configuring basic settings of an Ethernet interface or subinterface···························································5
Configuring an Ethernet subinterface·········································································································6
Configuring the link mode of an Ethernet interface····················································································7
Configuring jumbo frame support···············································································································7
Configuring physical state change suppression on an Ethernet interface ·················································8
Configuring dampening on an Ethernet interface·······················································································9
Enabling link flapping protection on an interface······················································································10
Configuring FEC·······································································································································11
Enabling loopback testing on an Ethernet interface·················································································12
Configuring generic flow control on an Ethernet interface ·······································································12
Enabling EEE on an Ethernet interface····································································································13
Setting the statistics polling interval·········································································································14
Forcibly bringing up a fiber port················································································································14
Configuring a Layer 2 Ethernet interface ·········································································································16
Configuring storm suppression ················································································································16
Configuring storm control on an Ethernet interface··················································································17
Setting speed options for autonegotiation on an Ethernet interface ························································18
Setting the MDIX mode of an Ethernet interface······················································································19
Testing the cable connection of an Ethernet interface·············································································20
Enabling bridging on an Ethernet interface······························································································20
Configuring a Layer 3 Ethernet interface or subinterface·················································································21
Setting the MTU for an Ethernet interface or subinterface·······································································21
Displaying and maintaining an Ethernet interface or subinterface···································································21

1
Configuring Ethernet interfaces
The Switch Series supports Ethernet interfaces, management Ethernet interfaces, and Console
interfaces.
Your device supports the following types of Ethernet interfaces:
•
Layer 2 Ethernet interfaces—Physical Ethernet interfaces operating at the data link layer
(Layer 2) to switch packets.
•
Layer 3 Ethernet interfaces—Physical Ethernet interfaces operating at the network layer
(Layer 3) to route packets. You can assign an IP address to a Layer 3 Ethernet interface.
•
Layer-configurable Ethernet interfaces—Physical Ethernet interfaces that can be configured
to operate in bridge mode as Layer 2 Ethernet interfaces or in route mode as Layer 3 Ethernet
interfaces.
•
Layer 3 Ethernet subinterfaces—Logical interfaces operating at the network layer. You can
assign an IP address to a Layer 3 Ethernet subinterface. On a Layer 3 Ethernet interface, you
can create multiple Layer 3 subinterfaces.
This chapter describes how to configure management Ethernet interfaces and Ethernet interfaces.
Configuring a management Ethernet interface
About management Ethernet interface
A management Ethernet interface uses an RJ-45/LC connector. You can connect the interface to a
PC for software loading and system debugging, or connect it to a remote NMS for remote system
management.
Restrictions and guidelines
The management Ethernet interface can be a copper port or fiber port.
•
By default, the duplex mode is auto for a copper port and full for a fiber port. The duplex
command cannot modify the duplex mode to any value other than the default for the copper port
or fiber port.
•
By default, the speed is auto for a copper port and 1000 Mbps for a fiber port. The speed
command cannot modify the speed to any value other than the default for the copper port or
fiber port.
In standalone mode, when the switch has multiple management Ethernet interfaces, only the
management Ethernet interface on the active MPU processes management traffic.
In IRF mode, when an IRF system has multiple management Ethernet interfaces, only the
management Ethernet interface on the global active MPU processes management traffic.
Configuration procedure
Step
Command
Remarks
1. Enter system view. system-view N/A
2. Enter management
Ethernet interface view. interface
M-GigabitEthernet
interface-number N/A
3. (Optional.) Set the
interface description.description text The default setting is
M-GigabitEthernet0/0/0 Interface.
4. (Optional.) Shut down
the interface. shutdown By default, the management Ethernet
interface is up.

2
Ethernet interface naming conventions
When the switches operate in standalone mode, the Ethernet interfaces are named in the format of
interface-type A/B/C, where the following definitions apply:
•
A—Represents the slot number of a card.
•
B—Represents the number of a subcard on a card. If the card has no subcards, this value is 0.
•
C—Represents the number of an interface.
When the switches operate in IRF mode, the Ethernet interfaces are named in the format of
interface-type A/B/C/D, where the following definitions apply:
•
A—Represents the member ID of an IRF member switch. This value is 1 or 2.
•
B—Represents the slot number of the card.
•
C—Represents the number of a subcard on a card. If the card has no subcards, this value is 0.
•
D—Represents the number of an interface.
Configuring common Ethernet interface settings
This section describes the settings common to Layer 2 Ethernet interfaces, Layer 3 Ethernet
interfaces, and Layer 3 Ethernet subinterfaces. For more information about the settings specific to
Layer 2 Ethernet interfaces or subinterfaces, see "Configuring a Layer 2 Ethernet interface." For
more information about the settings specific to Layer 3 Ethernet interfaces or subinterfaces, see
"Configuring a Layer 3 Ethernet interface or subinterface."
Configuring a combo interface (single combo interface)
A combo interface is a logical interface that physically comprises one fiber combo port and one
copper combo port. The two ports share one forwarding channel and one interface view. As a result,
they cannot work simultaneously. When you activate one port, the other port is automatically
disabled. In the interface view, you can activate the fiber or copper combo port, and configure other
port attributes such as the interface rate and duplex mode.
Configuration prerequisites
Before you configure combo interfaces, complete the following tasks:
•
Determine the combo interfaces on your device. Identify the two physical interfaces that belong
to each combo interface according to the marks on the device panel.
•
Use the display interface command to determine which port (fiber or copper) of each combo
interface is active:
If the copper port is active, the output includes "Media type is twisted pair."
If the fiber port is active, the output does not include this information.
Changing the active port of a combo interface
Step
Command
Remarks
1. Enter system view. system-view N/A
2. Enter Ethernet interface
view. interface interface-type
interface-number N/A
3. Activate the copper combo
port or fiber combo port. combo enable {copper |fiber } By default, the fiber combo port is
active.

3
Splitting a 40-GE interface and combining 10-GE breakout
interfaces
Restrictions and guidelines
This feature is not supported on non-default MDCs.
On an LSQM1QGS24RSG0 interface module, this feature is supported on interfaces 1 through 16.
Splitting a 40-GE interface into four 10-GE breakout interfaces
IMPORTANT:
For this configuration to survive a reboot, save the configuration before rebooting the switch.
You can use a 40-GE interface as a single interface. To improve port density, reduce costs, and
improve network flexibility, you can also split a 40-GE interface into four 10-GE breakout interfaces.
The 10-GE breakout interfaces support the same configuration and attributes as common 10-GE
interfaces, except that they are numbered differently.
For example, you can split 40-GE interface FortyGigE 1/0/1 into four 10-GE breakout interfaces
Ten-GigabitEthernet 1/0/1:1 through Ten-GigabitEthernet 1/0/1:4.
A 40-GE interface split into four 10-GE breakout interfaces must use a dedicated 1-to-4 cable. For
more information about the cable, see the installation guide.
After you configure this feature on a 40-GE interface on an interface card, reboot the interface card to
make the configuration take effect. Do not assign the changed interfaces to any non-default MDC
before rebooting the interface card.
To split a 40-GE interface into four 10-GE breakout interfaces:
Step
Command
Remarks
1. Enter system view. system-view N/A
2. Enter 40-GE interface view. interface interface-type
interface-number N/A
3. Split the 40-GE interface into
four 10-GE breakout
interfaces. using tengige By default, a 40-GE interface is not
split and operates as a single
interface.
Combining four 10-GE breakout interfaces into a 40-GE interface
IMPORTANT:
For this configuration to survive a reboot, save the configuration before rebooting the switch.
If you need higher bandwidth on a single interface, you can combine the four 10-GE breakout
interfaces into a 40-GE interface.
After you combine the four 10-GE breakout interfaces, replace the dedicated 1-to-4 cable with a
dedicated 1-to-1 cable or a 40-GE transceiver module. For more information about the cable or
transceiver module, see the installation guide.
After you configure this feature on a 10-GE breakout interface on an interface card, reboot the
interface card to make the configuration take effect. Do not assign the changed interfaces to any
non-default MDC before rebooting the interface card.
To combine four 10-GE breakout interfaces into a 40-GE interface:

4
Step
Command
Remarks
1. Enter system view.
system-view
N/A
2. Enter the view of any 10-GE
breakout interface. interface interface-type
interface-number N/A
3. Combine the four 10-GE
breakout interfaces into a
40-GE interface. using fortygige By default, a 40-GE interface is
not split and operates as a single
interface.
Changing the interface type of 100-GE interfaces in batches
IMPORTANT:
•
This feature is not supported on non-default MDCs.
•The interfaces to be changed in batches must be on the same card.
Restrictions and guidelines
This feature is supported only on the LSQM1CQGS12SG0, and LSQM1TGS24QSFD0 interface
modules.
On the LSQM1CQGS12SG0 interface modules, after you change each group of 40-GE interfaces to
100-GE interfaces, only interfaces 1, 4, 7, and 10 are available. On the LSQM1TGS24QSFD0
interface modules, after you change each group of 40-GE interfaces to 100-GE interfaces, only
interface 25 is available.
Reboot the interface module after you configure this feature. Do not assign the changed interfaces to
any non-default MDC before rebooting the interface module.
For this configuration to survive a reboot, save the running configuration before rebooting the device.
Changing 100-GE interfaces to 40-GE interfaces in batches
To improve network flexibility, you can change 100-GE interfaces to 40-GE interfaces in batches. For
this configuration to succeed, you must specify the available interface numbers.
To change 100-GE interfaces to 40-GE interfaces in batches:
Step
Command
Remarks
1. Enter system view. system-view N/A
2. Change 100-GEinterfaces to
40-GE interfaces.
using
fortygige-from-hundredgige
interface { interface-type
interface-number [ to
interface-type
interface-number ] } &<1-24>
N/A
Changing 40-GE interfaces to 100-GE interfaces in batches
To improve network flexibility, you can change 40-GE interfaces to 100-GE interfaces in batches. For
this configuration to succeed, make sure all interfaces in one group are specified in this
configuration.
On the LSQM1CQGS12SG0 interface modules, three continuous interfaces starting from 1 are
organized into one group. On the LSQM1TGS24QSFD0 interface modules, two continuous
interfaces starting from 1 are organized into one group.
To change 40-GE interfaces to 100-GE interfaces in batches:

5
Step
Command
Remarks
1. Enter system view.
system-view
N/A
2. Change 40-GE interfaces to
100-GE interfaces.
using
hundredgige-from-fortygige
interface { interface-type
interface-number [ to
interface-type
interface-number ] } &<1-24>
N/A
Configuring basic settings of an Ethernet interface or
subinterface
About basic settings of an Ethernet interface
You can configure an Ethernet interface to operate in one of the following duplex modes:
•
Full-duplex mode—The interface can send and receive packets simultaneously.
•
Half-duplex mode—The interface can only send or receive packets at a given time.
•
Autonegotiation mode—The interface negotiates a duplex mode with its peer.
You can set the speed of an Ethernet interface or enable it to automatically negotiate a speed with its
peer.
Restrictions and guidelines
The internal interfaces of OAP modules do not support the duplex mode and speed configuration.
For more information, see OAA Configuration Guide.
You cannot configure both 10 Mbps and half duplex mode for interfaces with copper port transceiver
modules installed on the following interface modules:
•
FD interface modules
•
SC interface modules: LSQM2GP24TSSC0, LSQM2GP44TSSC0, LSQM2GT24PTSSC0,
LSQM2GT24TSSC0, LSQM2GT48SC0, LSQM3GP44TSSC0, and LSQM4GV48SC0
Set the duplex mode to full and speed to 1000 Mbps for the specified 10GE interfaces with 1-Gbps
transceiver modules installed on the following interface modules:
•
FD interface modules: interfaces 29 through 36 on LSQM1GP40TS8FD0, interfaces 17 through
24 on LSQM1TGS24FD0, and interfaces 13 through 20 on LSQM1XPT12TSFD0
•
FE interface modules: interfaces 17 through 24 on LSQM1TGS48RFE0
The last eight 10-GE interfaces on the LSQM1TGT24FD0 interface module support only the speed
higher than 100 Mbps. The system prompts this interface speed restriction when you configure an
unsupported speed.
Configuration procedure
Step
Command
Remarks
1. Enter system view.
system-view
N/A
2. Enter Ethernet interface
view. interface interface-type
interface-number N/A
3. Set the description for
the Ethernet interface. description text The default setting is interface-name
Interface.
4. Set the duplex mode for
the Ethernet interface. duplex { auto | full | half } Fiber ports do not support the half
keyword.

6
Step
Command
Remarks
By default, the duplex mode is auto for
Ethernet interfaces.
For interfaces at two ends of a physical
link to operate correctly, configure the
same duplex mode for them.
Interfaces that operate in 1000 Mbps or a
higher speed do not support the half
keyword and cannot autonegotiate the
half duplex mode with the peer.
5. Set the speed for the
Ethernet interface. speed { 10 | 100 |1000 | 2500 |
5000 |10000 |40000 |100000
| auto }
By default, an Ethernet interface
autonegotiates the speed with its peer.
Support for the keywords of this command
varies by interface type. For more
information, execute the speed ?
command in interface view.
For interfaces at two ends of a physical
link to operate correctly, configure the
same speed for them.
The speed of a 10-Gbps or faster fiber
port cannot be configured or
autonegotiated as 100 Mbps or lower.
6. Set the expected
bandwidth for the
Ethernet interface. bandwidth bandwidth-value By default, the expected bandwidth (in
kbps) is the interface baud rate divided by
1000.
7. Restore the default
settings for the Ethernet
interface. default N/A
8. Bring up the Ethernet
interface. undo shutdown
B y default, an Ethernet interface is up.
The shutdown, port up-mode, and
loopback commands are mutually
exclusive.
Configuring an Ethernet subinterface
When you configure an Ethernet subinterface, follow these restrictions and guidelines:
•
To transmit packets between a local Ethernet subinterface and a remote Ethernet subinterface,
configure them with the same subinterface number and VLAN ID.
•
Do not use the VLAN whose ID is an Ethernet subinterface number.
To configure an Ethernet subinterface:
Step
Command
Remarks
1. Enter system view. system-view N/A
2. Create an Ethernet
subinterface. interface interface-type
interface-number.subnumber N/A
3. Set the description for the
Ethernet subinterface. description text The default setting is
interface-name Interface.
4. Restore the default settings
for the Ethernet subinterface. default N/A
5. Set the expected bandwidth
for the Ethernet subinterface.
bandwidth bandwidth-value By default, the expected
bandwidth (in kbps) is the

7
Step
Command
Remarks
interface baud rate divided by
1000.
6. Bring up the Ethernet
subinterface. undo shutdown
By default, an Ethernet
subinterface is up.
Do not use the shutdown
command on an interface
configured with the loopback
command.
Configuring the link mode of an Ethernet interface
CAUTION:
After you change th
e link mode of an Ethernet interface, all commands (except the shutdown
and
combo enable
commands) on the Ethernet interface are restored to their defaults in the new link
mode.
The Ethernet interfaces can operate either as Layer 2 or Layer 3 Ethernet interfaces. You can set the
link mode to bridge or route.
In an IRF 3.1 system, Ethernet interfaces on PEXs cannot be configured as Layer 3 Ethernet
interfaces.
The following interfaces do not support the link mode configuration:
•
IRF physical interfaces (see Virtual Technologies Configuration Guide).
•
Reflector ports used in remote source mirroring groups (see Network Management and
Monitoring Configuration Guide).
To configure the link mode of an Ethernet interface:
Step
Command
Remarks
1. Enter system view.
system-view
N/A
2. Enter Ethernet interface
view. interface interface-type
interface-number N/A
3. Configure the link mode of
the Ethernet interface. port link-mode { bridge | route } By default, an Ethernet
interfaces operates in bridge
mode.
Configuring jumbo frame support
An Ethernet interface might receive frames larger than the standard Ethernet frame size during
high-throughput data exchanges, such as file transfers. These frames are called jumbo frames.
The Ethernet interface processes jumbo frames in the following ways:
•
When you configure the Ethernet interface to deny jumbo frames by using the undo
jumboframe enable command, the Ethernet interface discards jumbo frames.
•
When you configure the Ethernet interface with jumbo frame support, the Ethernet interface
performs the following operations:
Processes jumbo frames within the specified length.
Discards jumbo frames that exceed the specified length.
To configure jumbo frame support in interface view:

8
Step
Command
Remarks
1. Enter system view.
system-view
N/A
2. Enter Ethernet interface
view. interface interface-type
interface-number N/A
3. Configure jumbo frame
support. jumboframe enable [ size ]
By default, an Ethernet interface
allows jumbo frames within 9126
bytes to pass through.
If you set the size argument multiple
times, the most recent configuration
takes effect.
Configuring physical state change suppression on an
Ethernet interface
The physical link state of an Ethernet interface is either up or down. Each time the physical link of an
interface comes up or goes down, the interface immediately reports the change to the CPU. The
CPU then performs the following operations:
•
Notifies the upper-layer protocol modules (such as routing and forwarding modules) of the
change for guiding packet forwarding.
•
Automatically generates traps and logs to inform users to take the correct actions.
To prevent frequent physical link flapping from affecting system performance, configure physical
state change suppression. You can configure this feature to suppress only link-down events, only
link-up events, or both. If an event of the specified type still exists when the suppression interval
expires, the system reports the event to the CPU.
Configuration restrictions and guidelines
Do not enable this feature on an interface with RRPP, spanning tree protocols, or Smart Link
enabled.
This command, the dampening command, and the port link-flap protect enable command are
mutually exclusive on an interface.
You can configure different suppression intervals for link-up and link-down events.
If you execute the link-delay command multiple times on an interface, the following rules apply:
•
You can configure the suppression intervals for link-up and link-down events separately.
•
If you configure the suppression interval multiple times for link-up or link-down events, the most
recent configuration takes effect.
Configuration procedure
To configure physical state change suppression on an Ethernet interface:
Step
Command
Remarks
1. Enter system view. system-view N/A
2. Enter Ethernet
interface view. interface interface-type
interface-number N/A
3. Configure physical
state change
suppression.
link-delay {down |up }
[
msec
]
delay-time By default, an Ethernet interface immediately
reports the physical state change to the CPU.

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Configuring dampening on an Ethernet interface
The interface dampening feature uses an exponential decay mechanism to prevent excessive
interface flapping events from adversely affecting routing protocols and routing tables in the network.
Suppressing interface state change events protects the system resources.
If an interface is not dampened, its state changes are reported. For each state change, the system
also generates an SNMP trap and log message.
After a flapping interface is dampened, it does not report its state changes to the CPU. For state
change events, the interface only generates SNMP trap and log messages.
Parameters
•
Penalty—The interface has an initial penalty of 0. When the interface flaps, the penalty
increases by 1000 for each down event until the ceiling is reached. It does not increase for up
events. When the interface stops flapping, the penalty decreases by half each time the half-life
timer expires until the penalty drops to the reuse threshold.
•
Ceiling—The penalty stops increasing when it reaches the ceiling.
•
Suppress-limit—The accumulated penalty that triggers the device to dampen the interface. In
dampened state, the interface does not report its state changes to the CPU. For state change
events, the interface only generates SNMP traps and log messages.
•
Reuse-limit—When the accumulated penalty decreases to this reuse threshold, the interface is
not dampened. Interface state changes are reported to the upper layers. For each state change,
the system also generates an SNMP trap and log message.
•
Decay—The amount of time (in seconds) after which a penalty is decreased.
•
Max-suppress-time—The maximum amount of time the interface can be dampened. If the
penalty is still higher than the reuse threshold when this timer expires, the penalty stops
increasing for down events. The penalty starts to decrease until it drops below the reuse
threshold.
When configuring the dampening command, follow these rules to set the values mentioned above:
•
The ceiling is equal to 2(Max-suppress-time/Decay) × reuse-limit. It is not user configurable.
•
The configured suppress limit is lower than or equal to the ceiling.
•
The ceiling is lower than or equal to the maximum suppress limit supported.
Figure 1 shows the change rule of the penalty value. The lines t0and t2indicate the start time and
end time of the suppression, respectively. The period from t0to t2indicates the suppression period, t0
to t1indicates the max-suppress-time, and t1to t2indicates the complete decay period.

10
Figure 1 Change rule of the penalty value
Configuration restrictions and guidelines
When you configure dampening on an Ethernet interface, follow these restrictions and guidelines:
•
The dampening, link-delay, and port link-flap protect enable commands are mutually
exclusive on an interface.
•
The dampening command does not take effect on the administratively down events. When you
execute the shutdown command, the penalty restores to 0, and the interface reports the down
event to the upper-layer protocols.
•
Do not enable the dampening feature on an interface with RRPP, MSTP, or Smart Link enabled.
Configuration procedure
To configure dampening on an Ethernet interface:
Step
Command
Remarks
1. Enter system view. system-view N/A
2. Enter Ethernet
interface view. interface interface-type
interface-number
N/A
3. Enable dampening on
the interface. dampening [half-life reuse
suppress max-suppress-time ]By default, interface dampening is
disabled on Ethernet interfaces.
Enabling link flapping protection on an interface
Link flapping on an interface changes network topology and increases the system overhead. For
example, in an active/standby link scenario, when interface status on the active link changes
between UP and DOWN, traffic switches between active and standby links. To solve this problem,
configure this feature on the interface.
Not suppressed Not suppressedSuppressed
Penalty
Time
Reuse limit
Suppress limit
Ceiling
t
0 t 1 t
2

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With this feature enabled on an interface, when the interface goes down, the system enables link
flapping detection. During the link flapping detection interval, if the number of detected flaps reaches
or exceeds the link flapping detection threshold, the system shuts down the interface.
Configuration restrictions and guidelines
This feature takes effect only if it is configured in both the system view and interface view.
The dampening, link-delay, and port link-flap protect enable commands are mutually exclusive
on an Ethernet interface.
To bring up an interface that has been shut down by link flapping protection, execute the undo
shutdown command.
In the display interface command output, the Link-Flap DOWN value of the Current state field
indicates that the interface has been shut down by link flapping protection.
Configuration procedure
To enable link flapping protection on an Ethernet interface:
Step
Command
Remarks
1. Enter system view. system-view N/A
2. Enable link flapping
protection globally. link-flap protect enable By default, link flapping protection
is disabled globally.
3. Enter Ethernet interface
view. interface interface-type
interface-number N/A
4. Enable link flapping
protection on the Ethernet
interface.
port link-flap protect enable
[interval interval |threshold
threshold
]
*
By default, link flapping protection
is disabled on an Ethernet
interface.
Configuring FEC
About FEC
The forward error correction (FEC) feature corrects packet errors to improve transmission quality. It
attaches correction information to a packet at the sending end, and corrects error codes generated
during transmission at the receiving end based on the correction information. You can set the FEC
mode as needed.
Restrictions and guidelines
This feature is supported only on 100-GE interfaces.
A 100-GE interface connected through a copper cable or installed with a 40-Gbps transceiver
module does not support FEC. If FEC has been configured on the interface, use the undo port fec
mode command to restore the default.
When the FEC mode is set to auto on an interface, the actual FEC mode of the interface depends on
the model of the transceiver module installed. To view the actual FEC mode, see the FEC mode field
in the display interface command output.
Make sure you set the same FEC mode for both interfaces of a link.
Procedure
Step
Command
Remarks
1. Enter system view. system-view N/A
2. Enter Ethernet interface
view. interface interface-type
interface-number N/A