H3C S9500E Series User manual

H3C S9500E Series Routing Switches
Interface Configuration Guide
Hangzhou H3C Technologies Co., Ltd.
http://www.h3c.com
Software version: S9500E-CMW520-R1828P04
Document version: 6W182-20140823

Copyright © 2013-2014, Hangzhou 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 Hangzhou H3C Technologies Co., Ltd.
Trademarks
H3C, , H3CS, H3CIE, H3CNE, Aolynk, , H3Care, , IRF, NetPilot, Netflow,
SecEngine, SecPath, SecCenter, SecBlade, Comware, ITCMM and HUASAN are trademarks of
Hangzhou H3C Technologies Co., Ltd.
All other trademarks that may be mentioned in this manual are the property of their respective owners
Notice
The information in this document is subject to change without notice. Every effort has been made in the
preparation of this document to ensure accuracy of the contents, but all statements, information, and
recommendations in this document do not constitute the warranty of any kind, express or implied.

Preface
The H3C S9500E documentation set includes 14 configuration guides, which describe the software
features for the H3C S9500E Series Routing Switches and guide you through the software configuration
procedures. These configuration guides also provide configuration examples to help you apply software
features to different network scenarios.
The Interface Configuration Guide describes the configuration of Ethernet, POS, loopback, and null
interfaces.
This preface includes:
•Audience
•Conventions
•About the H3C S9500E documentation set
•Obtaining documentation
•Technical support
•Documentation feedback
Audience
This documentation is intended for:
•Network planners
•Field technical support and servicing engineers
•Network administrators working with the S9500E series
Conventions
This section describes the conventions used in this documentation set.
Command conventions
Convention Descri
p
tion
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 at least one.
[ x | y | ... ] *
Asterisk marked square brackets enclose optional syntax choices separated by vertical

Convention Descri
p
tion
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 Descri
p
tion
Boldface Window names, button names, field names, and menu items are in Boldface. For
example, the New User window appears; click OK.
> Multi-level menus are separated by angle brackets. For example, File > Create > Folder.
Symbols
Convention Descri
p
tion
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
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 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 card, such as a firewall, load-balancing, NetStream, SSL VPN, IPS,
or ACG card.
Port numbering in examples
The port numbers in this document are for illustration only and might be unavailable on your device.
About the H3C S9500E documentation set
The H3C S9500E documentation set includes:
Cate
g
or
y
Documents Pur
p
oses
Product description and
specifications
Marketing brochures Describe product specifications and benefits.
Technology white papers
Provide an in-depth description of software features
and technologies.
Card datasheets Describe card specifications, features, and
standards.
Hardware specifications
and installation
Regulatory compliance
and safety information
Provides regulatory information and the safety
instructions that must be followed during installation.
Installation guide Provides a complete guide to hardware installation
and hardware specifications.
H3C Pluggable SFP
[SFP+][XFP] Transceiver
Modules Installation
Guide
Guides you through installing SFP/SFP+/XFP
transceiver modules.
Adjustable Slider Rail
Installation Guide
Guides you through installing adjustable slider rails
to a rack.
H3C Transceiver Modules
User Guide
Describes transceiver modules available for the H3C
high-end network products, their external views, and
specifications.
Software configuration
Configuration guides Describe software features and configuration
procedures.
Command references Provide a quick reference to all available
commands.
Operations and
maintenance
System log messages Explains the system log messages.
Trap messages Explains the trap messages.
MIB Companion Describes the MIBs for the software release.
Release notes
Provide information about the product release,
including the version history, hardware and software
compatibility matrix, version upgrade information,
technical support information, and software
upgrading.


Obtaining documentation
Access the most up-to-date H3C product documentation on the World Wide Web
at http://www.h3c.com.
Click the links on the top navigation bar to obtain different categories of product documentation:
[Technical Support & Documents > Technical Documents]—Provides hardware installation, software
upgrading, and software feature configuration and maintenance documentation.
[Products & Solutions]—Provides information about products and technologies, as well as solutions.
[Technical Support & Documents > Software Download]—Provides the documentation released with the
software version.
Technical support
servi[email protected]
http://www.h3c.com
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 guidelines ··················································································································································1
Configuration procedure··················································································································································1
Configuring Ethernet interfaces··································································································································· 3
Ethernet interface types ····················································································································································3
Configuring general Ethernet interfaces and subinterfaces··························································································3
Ethernet interface numbering conventions ·············································································································3
Ethernet interface configuration task list ················································································································4
Configuring a combo interface·······························································································································4
Configuring the operating mode for a 10-GE interface·······················································································5
Switching the link mode of an Ethernet interface between Layer 2 and Layer 3 ··············································6
Configuring basic settings of an Ethernet interface or subinterface ···································································7
Bringing up Ethernet interfaces and subinterfaces································································································8
Configuring flow control on an Ethernet interface································································································9
Setting the statistics polling interval on an Ethernet interface··············································································9
Configuring physical state change suppression on an Ethernet interface······················································· 10
Configuring loopback testing on an Ethernet interface····················································································· 11
Configuring Layer 2 Ethernet interfaces ······················································································································ 11
Layer 2 Ethernet interface configuration task list ······························································································· 11
Configuring a manual port group ······················································································································· 12
Setting speed options for auto negotiation on an Ethernet interface······························································· 12
Configuring storm suppression for an Ethernet interface ·················································································· 14
Configuring jumbo frame support ······················································································································· 14
Setting the MDI mode of an Ethernet interface ·································································································· 15
Forcibly bringing up an Ethernet interface ········································································································· 16
Configuring the connection mode of an Ethernet interface ·············································································· 17
Configuring Layer 3 Ethernet interface and subinterfaces························································································· 17
Setting the MTU for an Ethernet interface or subinterface ················································································ 17
Displaying and maintaining Ethernet interfaces ········································································································· 18
Configuring POS interfaces·······································································································································19
Overview········································································································································································· 19
SONET···································································································································································· 19
SDH········································································································································································· 19
POS········································································································································································· 19
Configuration procedure··············································································································································· 19
Displaying and maintaining POS interfaces ··············································································································· 21
POS interface configuration examples ························································································································ 22
Directly connecting switches through POS interfaces························································································ 22
Connecting switches through POS interfaces across frame relay···································································· 22
Troubleshooting POS interfaces···································································································································· 24
Configuring loopback and null interfaces················································································································25
Configuring a loopback interface ································································································································ 25
Introduction ···························································································································································· 25
Configuration procedure ······································································································································ 25
Configuring a null interface ·········································································································································· 26
Introduction ···························································································································································· 26
Configuration procedure ······································································································································ 26

ii
Displaying and maintaining loopback and null interfaces························································································ 27
Index ···········································································································································································28

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 perform the shutdown command in interface range
view to shut down a range of interfaces.
Failure of applying a command on one member interface does not affect the application of the command
on the other member interfaces. If applying a command on one member interface fails, the system
displays an error message and continues with the next member interface.
Configuration 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.
•Do not assign an aggregate interface and any of its member interfaces to an interface range at the
same time. 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 only limited by the system resources. To
guarantee bulk interface configuration performance, configure interface range names fewer than
1000.
Configuration procedure
To bulk configure interfaces:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter interface range
view.
•Method 1:
interface range { interface-type
interface-number [ to interface-type
interface-number ] } &<1-5>
•Method 2:
interface range name name
[ interface { interface-type
interface-number [ to interface-type
interface-number ] } &<1-5> ]
Use either method.
By using method 2, 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. Display commands
available for the first
interface in the
interface range.
Enter ?at the interface range prompt. Optional.

2
Step Command Remarks
4. Perform available
commands to
configure the
interfaces.
Available commands vary by interface.
N/A
5. Verify the
configuration. display this Optional.

3
Configuring Ethernet interfaces
Ethernet interface types
Ethernet is the most widespread wired LAN technology due to its flexibility, simplicity, and easy
implementation. 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 traffic.
•Layer 3 Ethernet interfaces—Physical Ethernet interfaces operating at the network layer (Layer 3) to
route traffic. 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. By creating subinterfaces on a Layer 3 Ethernet
interface, you enable the interface to carry packets for multiple VLANs.
The switch does not support Layer 3 Ethernet interfaces, Layer 3 Ethernet subinterfaces, Layer 3
aggregate interfaces, and Layer 3 aggregate subinterfaces when it is operating in standard mode. For
more information about system operating modes, see Fundamentals Configuration Guide. For more
information about the models of the Ethernet interface cards, see the installation guide.
On a switch operating in IRF mode and enabled with enhanced IRF mode, you cannot create Layer 3
Ethernet interfaces, Layer 3 Ethernet subinterfaces, Layer 3 aggregate interfaces, or Layer 3 aggregate
subinterfaces.
Configuring general Ethernet interfaces and
subinterfaces
By default, Ethernet interfaces, VLAN interfaces, and aggregate interfaces are in DOWN state. Before
configuring these interfaces, use the undo shutdown command to bring them up.
Ethernet interface numbering conventions
When the switch operates in standalone mode, an Ethernet interface is numbered in the format of
interface type A/B/C, where:
•A is the slot number of the card where the Ethernet interface resides.
•B is the number of the sub-card where the Ethernet interface resides.
If the card does not have any sub-card, B is fixed at 0.
•C is the interface number.
When the switch operates in IRF mode, an Ethernet interface is numbered in the format of interface type
A/B/C/D, where:

4
•A is the ID of the IRF member switch where the Ethernet interface resides.
A can be 1 or 2.
•B is the slot number of the card where the Ethernet interface resides.
•C is the number of the sub-card where the Ethernet interface resides.
If the card does not have any sub-card, C is fixed at 0.
•D is the interface number.
Ethernet interface configuration task list
Task Remarks
Configuring a combo interface Optional.
Configuring the operating mode for a 10-GE interface Optional.
Switching the link mode of an Ethernet interface between Layer 2 and Layer 3 Optional.
Configuring basic settings of an Ethernet interface or subinterface Optional.
Bringing up Ethernet interfaces and subinterfaces Optional.
Configuring flow control on an Ethernet interface Optional.
Setting the statistics polling interval on an Ethernet interface Optional.
Configuring physical state change suppression on an Ethernet interface Optional.
Configuring loopback testing on an Ethernet interface Optional.
Configuring a combo interface
CAUTION:
•When you activate the fiber port of a combo interface, the switch removes the current port settings (such
as rate, duplex mode, and MDI), if the fiber port does not support them.
•You cannot bind a combo interface with an IRF port. For more information about IRF, see
IRF
Configuration Guide
.
A combo interface is a logical interface that comprises one optical (fiber) port and one electrical (copper)
port. The two ports share one forwarding channel, so they cannot work simultaneously. When you
enable one port, the other port is automatically disabled.
The fiber and copper ports of a combo interface share one interface view, in which you activate the fiber
or copper port, and configure other port attributes, such as the interface rate and duplex mode.
Configuration prerequisites
Before configuring a combo interface:
•Determine the combo interfaces on your device by checking the product specifications and identify
the two physical interfaces that compose each combo interface.
•Identify which port of the interface is active by using the display interface command. If the output
includes "Media type is twisted pair, Port hardware type is 1000_BASE_T," the copper port is
active. If the output includes "Media type is not sure, Port hardware type is No connector," the fiber
interface is active.

5
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 or fiber
port of the combo interface. combo enable {copper |fiber }
Optional.
By default, the copper port is
active.
Configuring the operating mode for a 10-GE interface
Introduction to the operating modes
A ten-GigabitEthernet (10-GE) interface operates in LAN or WAN mode:
•In LAN mode, the 10-GE interface transmits Ethernet packets, providing access to an Ethernet
network.
•In WAN mode, the 10-GE interface transmits synchronous digital hierarchy (SDH) packets,
providing access to an SDH network. In this mode, the interface supports only point-to-point
connections.
NOTE:
A
10-GE interface operating in WAN mode cannot communicate with a 10G POS interface. Both kinds
of interfaces encapsulate packets as SDH frames, but the SDH frames have incompatible formats.
Introduction to the J0 and J1 overhead bytes
SDH frames have diversified overhead bytes, which perform the operation and maintenance functions
such as hierarchical management of the transport network. J0 and J1 are used to provide internetworking
support between different countries, regions, or network devices of different manufacturers.
The regenerator section trace byte J0 is usually set to a section access point identifier. The sending end
stays connected with the receiving end by sending this byte.
The path trace byte J1, usually set to a high-order path access point identifier, functions in a similar to
keep the connection with the receiving end of the path.
To ensure smooth communication, the J0 and J1 bytes should be matched at the sending and receiving
ends.
Configuration procedure
To configure the operating mode for a 10-GE interface:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter ten-GigabitEthernet
interface view.
interface ten-gigabitethernet
interface-number N/A

6
Step Command Remarks
3. Set the 10-GE interface to
operate in LAN or WAN
mode.
port-mode {lan | wan }
Optional.
By default, a 10-GE interface
operates in LAN mode.
The port-mode command is not
available on a port where
loopback testing is being
performed.
4. Configure the J0 or J1 byte
when the 10-GE interface is
operating in WAN mode.
flag { j0 | j1 }sdh value
Optional.
By default, the value of the J0 and
J1 bytes is 0.
5. Configure the SD or SF
threshold when the 10-GE
interface is operating in
WAN mode.
threshold {sd | sf } value
Optional.
By default, the value of the SD
threshold is 10e-6 (the value
argument is 6),the value of the SF
threshold is 10e-4 (the value
argument is 4).
6. Set the protective action for
alarms when the 10 GE
interface is operating in
WAN mode.
alarm-detect {rdi |sd |sf } action
link-down
Optional.
By default, no protective action for
alarms is configured.
IMPORTANT:
The flag, threshold, and alarm-detect commands are available only when the 10-GE interface is
operating in WAN mode.
Switching the link mode of an Ethernet interface between Layer
2 and Layer 3
CAUTION:
•The switch supports this command when the operating mode is not the standard mode. The switch
operates in standard mode by default. For more information about system operating modes, see
Fundamentals Configuration Guide .
•After you chan
g
e the operatin
g
mode of an Ethernet interface, all the settin
g
s of the Ethernet interface
will restore to the default configuration in the new mode.
•The Ethernet interface link mode can be configured in either the system view or the Ethernet view and
when the two link modes are different, the one configured last takes effect.
•You cannot configure Layer 3 Ethernet interfaces as physical IRF ports.
Depending on the layer at which the switch processes received data packets, Ethernet interfaces on the
switch can operate either as Layer 2 Ethernet interfaces (in bridge mode), or as Layer 3 Ethernet
interfaces (in route mode). You can set the link mode of an Ethernet interface to bridge or route.
To change the link mode of an Ethernet interface:

7
Step Command Remarks
1. Enter system view. system-view N/A
2. Change the link mode of
Ethernet interfaces.
•(Method 1) In system view:
port link-mode { bridge | route }
interface-list
•(Method 2) In Ethernet interface
view:
a. interface interface-type
interface-number
b. port link-mode { bridge |
route }
Use either method.
By default, Ethernet interfaces
operate in bridge mode.
Configuring basic settings of an Ethernet interface or
subinterface
Configuring an Ethernet interface
CAUTION:
Because a 1000-Mbps interface cannot operate in half duplex mode, you cannot use the duplex half
command together with the following commands: speed 1000 and speed auto 1000 [ 10 | 100 ] *.
You can set an Ethernet interface to operate in one of the following duplex modes:
•Full-duplex mode (full)—Interfaces operating in this mode can send and receive packets
simultaneously.
•Half-duplex mode (half)—Interfaces operating in this mode can either send or receive packets at a
given time.
•Auto-negotiation mode (auto)—Interfaces operating in this mode determine a duplex mode
through auto-negotiation.
You can set the speed of an Ethernet interface or enable it to automatically negotiate a speed with its
peer. For auto-negotiation, you can also set speed options. The two ends can pick a speed only from the
options. For a 100-Mbps or 1000-Mbps Layer 2 Ethernet interface, you can also set speed options for
auto negotiation. The two ends can pick a speed only from the available options. For more information,
see "Setting speed options for auto negotiation on an Ethernet interface."
To configure basic Ethernet interface settings:
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 descriptive information
for the Ethernet interface. description text
Optional.
By default, the descriptive
information is "interface name +
Interface."

8
Step Command Remarks
4. Set the duplex mode. duplex { auto | full | half }
Optional.
The default setting is auto.
A fiber port does not support half
keyword.
10-GE interfaces do not support
this command.
5. Set the transmission rate. speed { 10 | 100 |1000 |auto }
Optional.
The default setting is auto.
6. Restore the default settings. default Optional.
7. Set the intended bandwidth. bandwidth bandwidth-value Optional.
Configuring an Ethernet subinterface
Ste
p
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 interface to
operate in Layer 3 mode. port link-mode route By default, an Ethernet interface
operates in Layer 2 mode.
4. Return to system view. quit N/A
5. Create an Ethernet
subinterface.
interface interface-type
interface-number.subnumber
This command also leads you to
Ethernet subinterface view.
6. Set the interface description. description text
Optional.
By default, the description of an
interface is in the format of
interface-name Interface. For
example, GigabitEthernet3/0/2.1
Interface.
7. Restore the default settings. default Optional.
NOTE:
For the local and remote Ethernet subinterfaces to transmit traffic correctly, confi
g
ure them with the same
subinterface number and VLAN ID.
You can configure IP-related settings on an Ethernet subinterface. For more information, see Layer 3—IP
Services Configuration Guide.
Bringing up Ethernet interfaces and subinterfaces
You can use the commands in this section to bring up a single Ethernet interface in Ethernet interface view,
or to bring up multiple Ethernet interfaces in port group view.
To bring up Ethernet interfaces:

9
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter Ethernet interface or
subinterface view, or port
group view.
•Enter Ethernet interface
view:
interface interface-type
interface-number
•Enter Ethernet
subinterface view:
interface interface-type
interface-number.subnum
ber
•Enter port group view:
port-group manual
port-group-name
Use any command.
To shut down an Ethernet interface or
subinterface, enter Ethernet interface or
subinterface view. To shut down all
Ethernet interfaces in a port group, enter
port group view.
You can enter Ethernet subinterface
view only when the Ethernet interface
operates in Layer 3 mode.
3. Bring up Ethernet interfaces. undo shutdown
Optional.
By default, Ethernet interfaces are in
DOWN state.
Configuring flow control on an Ethernet interface
You can avoid packet drops on a link by enabling flow control at both ends of the link. When traffic
congestion occurs at the receiving end, the receiving end sends a Pause frame to notify the sending end
to suspend sending packets.
To enable flow control 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 flow control. flow-control By default, flow control is disabled.
Setting the statistics polling interval 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. Set the statistics polling
interval. flow-interval interval The default interface statistics
polling interval is 300 seconds.
To display the interface statistics collected in the last polling interval, use the display interface command.

10
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 a port
goes up or comes down, the system immediately reports the change to the upper-layer protocol modules
(such as routing and forwarding modules) for packet transmission, and automatically generates traps
and logs, informing the user to take corresponding actions.
To prevent frequent physical link flapping from affecting system performance, configure physical state
change suppression to suppress the reporting of physical link state changes. The system reports a
physical layer change unless the physical layer state change is not recovered when the suppression
interval expires. If you want to obtain physical layer changes within the suppression interval, enable the
damping function with the link-delay enable trap updown command on the port. When the link-delay
enable trap updown command is configured on an interface, the interface does not report link layer state
changes to upper layer modules, but it generates traps and logs to inform the user to take corresponding
actions.
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 the physical state
change suppression interval. link-delay delay-time
By default, the physical state
change suppression interval on an
Ethernet interface is 1 second.
When the link-delay delay-time
command is configured, the
link-down or link-up event is not
reported to the CPU unless the
interface is still down or up when
the suppression interval
(delay-time) expires.
4. Configure the link-up event
suppression interval. link-delay delay-time mode up
By default, the physical state
change suppression interval on an
Ethernet interface is 1 second.
When the link-delay delay-time
mode up command is configured:
•The link-up event is not reported
to the CPU unless the interface
is still up when the suppression
interval (delay-time) expires.
•The link-down event is
immediately reported.
5. Enable the damping function
on the port. link-delay enable trap updown
Optional.
By default, the damping function is
disabled on a port.

11
Configuring loopback testing on an Ethernet interface
If an Ethernet interface does not operate correctly, you can enable loopback testing on it to identify the
problem.
If an Ethernet interface is in a loopback test, it does not forward data traffic.
Configuration restrictions and guidelines
•The loopback external configuration command is available only on the Ethernet interface that
supports 10-G XFP transceiver modules.
•Internal loopback testing can be enabled on interfaces in DOWN state, but not on those
administratively shut down.
•The speed, duplex, port-mode, mdi, combo enable, and shutdown commands are not available
during a loopback testing.
•During loopback testing, an Ethernet interface operates at its highest speed in full duplex mode.
When you disable loopback testing, the rate and duplex mode of the interface restore.
Configuration procedure
To enable loopback testing 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. Bring up the interface. undo shutdown N/A
4. Enable loopback testing. loopback { external | internal }
Optional.
By default, loopback testing is
disabled.
Configuring Layer 2 Ethernet interfaces
Layer 2 Ethernet interface configuration task list
Task Remarks
Configuring a manual port group Optional
Applicable to Layer 2 Ethernet interfaces
Setting speed options for auto negotiation on an
Ethernet interface
Optional
Applicable to 100-Mbps or 1000-Mbps Layer 2
Ethernet interfaces
Configuring storm suppression for an Ethernet
interface
Optional
Applicable to Layer 2 Ethernet interfaces
Configuring jumbo frame support Optional
Applicable to Layer 2 Ethernet interfaces

12
Task Remarks
Setting the MDI mode of an Ethernet interface Optional
Applicable to Layer 2 Ethernet interfaces
Forcibly bringing up an Ethernet interface Optional
Applicable to Layer 2 Ethernet interfaces
Configuring the connection mode of an Ethernet
interface
Optional
Applicable to Layer 2 Ethernet interfaces
Configuring a manual port group
Some interfaces on your device might use the same set of settings. To configure these interfaces in bulk
rather than one by one, you can assign them to a port group.
You create port groups manually. All settings made for a port group apply to all the member ports of the
group. For example, you can configure a traffic suppression threshold (see Configuring storm
suppression for an Ethernet interface) for multiple interfaces in bulk by assigning these interfaces to a port
group.
Even though the settings are made on the port group, they are saved on an interface basis rather than on
a port group basis. You can only view the settings in the view of each interface by use the display
current-configuration or display this command.
To configure a manual port group:
Step Command Remarks
1. Enter system view. system-view N/A
2. Create a manual port group
and enter manual port group
view.
port-group manual
port-group-name
By default, no manual port group is
created.
3. Assign Ethernet interfaces to
the manual port group. group-member interface-list By default, no Ethernet interface is
in any manual port group.
Setting speed options for auto negotiation on an Ethernet
interface
Speed auto negotiation enables an Ethernet interface to negotiate with its peer for the highest speed
supported by both ends by default. If the highest speed is not desirable, you can narrow down the speed
option list for negotiation.