HP FlexNetwork HSR6800 User manual

HP HSR6800 Routers
Interface
Configuration Guide
Part number: 5998-4488
Software version: HSR6800-CMW520-R3103
Document version: 6PW103-20130628

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Contents
Configuring Ethernet interfaces··································································································································· 1
Overview············································································································································································1
Performing general configurations ··································································································································1
Configuring a combo interface·······························································································································1
Configuring the operating mode for a 10-GE interface·······················································································2
Configuring basic settings of an Ethernet interface or subinterface ···································································3
Shutting down an Ethernet interface or subinterface····························································································4
Configuring physical state change suppression on an Ethernet interface··························································5
Configuring loopback testing on an Ethernet interface························································································5
Configuring the link mode of an Ethernet interface······························································································6
Setting a statistics polling interval···························································································································7
Enabling subinterface rate statistics collection on an Ethernet interface ····························································7
Configuring a Layer 2 Ethernet interface ·······················································································································8
Layer 2 Ethernet interface configuration task list ··································································································8
Configuring a port group ········································································································································8
Setting speed options for auto negotiation on an Ethernet interface··································································9
Configuring storm suppression ···························································································································· 10
Configuring jumbo frame support ······················································································································· 11
Enabling loopback detection on an Ethernet interface ····················································································· 11
Setting the MDI mode of an Ethernet interface ·································································································· 14
Testing the cable connection of an Ethernet interface······················································································· 14
Configuring storm control on an Ethernet interface··························································································· 15
Configuring a Layer 3 Ethernet interface or subinterface·························································································· 16
Layer 3 Ethernet interface configuration task list ······························································································· 16
Setting the MTU for an Ethernet interface or subinterface ················································································ 17
Configuring an Ethernet interface to operate in promiscuous mode ······························································· 17
Displaying and maintaining an Ethernet interface or subinterface··········································································· 17
Configuring ATM interfaces ······································································································································19
ATM interface································································································································································· 19
ATM ········································································································································································ 19
ATM interfaces available on the HSR6800 routers··························································································· 19
ATM interface features·········································································································································· 19
IMA·················································································································································································· 20
Configuring an ATM E1/T1 interface················································································································· 20
Troubleshooting ATM E1/T1 interfaces·············································································································· 21
Configuring an ATM OC-3c/STM-1 interface ············································································································ 21
Overview································································································································································ 21
Configuration procedure ······································································································································ 21
Displaying and maintaining ATM interfaces··············································································································· 22
Troubleshooting ATM interfaces ··································································································································· 22
Configuring WAN interfaces····································································································································23
Configuring a synchronous serial interface················································································································· 23
Enabling subinterface rate statistics collection on a serial interface········································································· 25
Displaying and maintaining serial interfaces·············································································································· 25
Configuring a CE1 interface········································································································································· 25
Configuring a CE1 interface in E1 mode ··········································································································· 26
Configuring a CE1 interface in CE1 mode ········································································································ 26
Configuring other CE1 interface parameters ····································································································· 27

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Configuring error packets diffusion restraint ······································································································ 28
Displaying and maintaining CE1 interfaces······································································································· 28
Configuring a CT1 interface········································································································································· 29
Configuring a CT1 interface in CT1 mode········································································································· 29
Configuring other CT1 interface parameters ····································································································· 29
Starting/terminating a BERT test on a CT1 interface························································································· 31
Configuring error packets diffusion restraint ······································································································ 31
Displaying and maintaining CT1 interfaces ······································································································· 32
Configuring an E1-F interface······································································································································· 32
Configuring an E1-F interface in framed mode·································································································· 32
Configuring an E1-F interface in unframed mode ····························································································· 33
Configuring other E1-F interface parameters ····································································································· 33
Configuring error packets diffusion restraint ······································································································ 34
Displaying and maintaining E1-F interfaces······································································································· 35
Configuring a T1-F interface ········································································································································· 35
Starting/terminating a BERT test on a T1-F interface························································································· 37
Configuring error packets diffusion restraint ······································································································ 37
Displaying and maintaining T1-F interfaces ······································································································· 38
Configuring a CE3 interface········································································································································· 38
Configuring a CE3 interface in E3 mode ··········································································································· 39
Configuring a CE3 interface in CE3 mode ········································································································ 39
Configuring other CE3 interface parameters ····································································································· 39
Displaying and maintaining CE3 interfaces······································································································· 40
Configuring a CT3 interface········································································································································· 41
Configuring a CT3 interface in T3 mode············································································································ 42
Configuring a CT3 interface in CT3 mode········································································································· 42
Configuring other CT3 interface parameters ····································································································· 43
Displaying and maintaining CT3 interfaces ······································································································· 45
Configuring POS interfaces·······································································································································47
Overview········································································································································································· 47
SONET···································································································································································· 47
SDH········································································································································································· 47
POS········································································································································································· 47
Configuring a POS interface ········································································································································ 47
Configuration procedure ······································································································································ 47
Enabling sub-interface rate statistics collection for a POS interface ································································ 49
Configuring the working mode of a POS interface card··························································································· 50
Displaying and maintaining POS interfaces ··············································································································· 50
POS interface configuration example·························································································································· 50
Directly connecting routers through POS interfaces ·························································································· 50
Connecting routers through POS interfaces across frame relay······································································· 51
Troubleshooting POS interfaces···································································································································· 52
Configuring CPOS interfaces····································································································································54
Overview········································································································································································· 54
SONET/SDH·························································································································································· 54
CPOS······································································································································································ 54
SDH frame structure ·············································································································································· 54
Terms······································································································································································· 55
Multiplexing E1/T1/E3/T3 channels to form STM-1 ························································································ 55
Calculating E1/T1/E3/T3 channel sequence numbers···················································································· 56
Overhead bytes ····················································································································································· 58
CPOS interface application scenario·················································································································· 58
Configuring a CPOS interface······································································································································ 59

iii
Configuring an E1 channel··········································································································································· 60
Configuring a T1 channel ············································································································································· 61
Configuring an E3 channel··········································································································································· 62
Configuring a T3 channel ············································································································································· 63
Configuring the working mode of an interface card ································································································· 64
Displaying and maintaining CPOS interfaces ············································································································ 64
CPOS interface configuration examples······················································································································ 65
CPOS-E1 interface configuration example ········································································································· 65
CPOS-E3 configuration example ························································································································· 67
Troubleshooting CPOS interfaces································································································································· 68
Interface physical status is UP, link protocol status is down, and loopback is detected ······························· 68
Configuring E-CPOS interfaces ·································································································································69
Overview········································································································································································· 69
SONET···································································································································································· 69
SDH········································································································································································· 69
E-CPOS ··································································································································································· 73
Configuring an E-CPOS interface································································································································· 74
Configuring an E-CPOS interface························································································································ 74
Configuring the operating mode of an E-CPOS interface/channel································································· 75
Displaying and maintaining E-CPOS interfaces ········································································································· 78
E-CPOS interface configuration examples··················································································································· 78
E-CPOS interface configuration example 1········································································································ 78
E-CPOS interface configuration example 2········································································································ 80
Troubleshooting E-CPOS interfaces······························································································································ 81
Symptom································································································································································· 81
Solution··································································································································································· 81
Configuring loopback and null interfaces················································································································84
Configuring a loopback interface ································································································································ 84
Introduction ···························································································································································· 84
Configuration procedure ······································································································································ 84
Configuring the null interface ······································································································································· 85
Introduction ···························································································································································· 85
Configuration procedure ······································································································································ 85
Displaying and maintaining loopback and null interfaces························································································ 85
Support and other resources ·····································································································································87
Contacting HP ································································································································································ 87
Subscription service ·············································································································································· 87
Related information························································································································································ 87
Documents······························································································································································ 87
Websites································································································································································· 87
Conventions ···································································································································································· 88
Index ···········································································································································································90

1
Configuring Ethernet interfaces
All configuration tasks in this chapter are independent and optional. You can perform these
configuration tasks in any order.
Overview
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 forward traffic within a subnet between hosts.
•Layer 3 Ethernet interfaces—Physical Ethernet interfaces operating at the network layer (Layer 3) to
forward traffic between different subnets. 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. For how a Layer 3 Ethernet
subinterface sends and receives VLAN-tagged packets, see Layer 2—LAN Switching Configuration
Guide.
Performing general configurations
This section describes the settings common to Layer 2 and Layer 3 Ethernet interfaces or subinterfaces.
For more information about the settings specific to a type of Ethernet interfaces, see "Configuring a Layer
2 Ethernet interface" and "Configuring a Layer 3 Ethernet interface or subinterface."
Configuring a combo interface
A combo interface is a logical interface that comprises one fiber port and one copper port. The two ports
share one forwarding channel and one interface view, so they cannot work simultaneously. When you
enable one port, the other port is automatically disabled.
The fiber combo port and the copper combo port share one interface view, in which 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 by checking the product specifications and identify
the two physical interfaces that compose each combo interface.
•Use the display interface command to determine whether the fiber port or copper port of the combo
interface is active. If the current port is the copper port, the output includes "Media type is twisted

2
pair." If the current port is the fiber port, the output includes "Media type is optical fiber." You can
use the display this command in combo interface view to determine whether the fiber port or
copper port of the combo interface is active. If the combo enable fiber command exists in the output,
the fiber port is active. Otherwise, the copper port is active.
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 copper combo 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, as follows:
•LAN mode—In LAN mode, the 10-GE interface transmits Ethernet packets, providing access to an
Ethernet network.
•WAN mode—In WAN mode, the 10-GE interface transmits SDH packets, providing access to an
SDH network. In this mode, the interface supports only point-to-point connections.
A 10-GE interface in WAN mode encapsulates Ethernet packets in SDH frames, and a 10G Packet over
SDH (POS) interface encapsulates PPP packets in SDH frames. However, these two types of interfaces
cannot communicate with each other, because the framing formats used by them are different.
Introduction to J0 and J1 overhead bytes
SDH frames have diversified overhead bytes, which accomplish the operation and maintenance
functions such as hierarchical management of the transmission network.
J0 and J1 are used to provide internetworking support between devices of different countries, regions, or
vendors.
The regenerator section trace byte J0 is usually set to a section access point identifier. The sending end
keeps the connection with the receiving end by sending this byte repeatedly.
The path trace byte J1, a byte in the high-order path overhead and usually set to a high-order path access
point identifier, functions in a similar way to keep the connection with the receiving end of the path.
To ensure smooth communication, the J0 and J1 bytes should be matched at, respectively, the sending
and receiving ends. For more information about SDH and SDH overhead bytes, see relevant technical
documentation.
Configuration procedure
To configure a 10-GE interface to operate in LAN or WAN mode:
Step Command Remarks
1. Enter system view. system-view N/A

3
Step Command Remarks
2. Enter 10-GE interface view. interface ten-gigabitethernet
interface-number N/A
3. Configure 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.
4. Configure the J0 or J1 byte
when the 10-GE interface is
operating in WAN mode.
flag { j0 | j1 }sdh flag-value
Optional.
By default, the value of the J0 and
J1 bytes is 0.
The flag command is applicable to 10-GE interfaces operating in WAN mode only.
Configuring basic settings of an Ethernet interface or
subinterface
Configuring an Ethernet interface
You can set an Ethernet interface to operate in one of these duplex modes:
•Full-duplex mode (full)—Interfaces that operate in this mode can send and receive packets
simultaneously.
•Half-duplex mode (half)—Interfaces that operate in this mode cannot send and receive packets
simultaneously.
•Auto-negotiation mode (auto)—Interfaces that operate in this mode negotiate a duplex mode with
their peers.
You can set the speed of an Ethernet interface or enable it to automatically negotiate a speed with its
peer. For a 100-Mbps or 1000-Mbps Layer 2 Ethernet interface, you can also set speed options for auto
negotiation. The two ends can select a speed only from the available options. For more information, see
"Setting speed options for auto negotiation on an Ethernet interface."
To configure 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 interface
description. description text
Optional.
By default, the description of an interface is
in the format of interface-name Interface.
For example, GigabitEthernet 4/0/1
Interface.
4. Set the duplex mode of
the interface. duplex { auto | full | half }
Optional.
By default, the duplex mode is full for
10-GE interfaces, and is auto for other
Ethernet interfaces.
Fiber ports do not support the half
keyword.

4
Step Command Remarks
5. Set the port speed. speed { 10 | 100 |1000 |
auto }
Optional.
The default setting is auto.
Fiber ports do not support the 10 or 100
keyword.
6. Set the intended
bandwidth for the
interface.
bandwidth bandwidth-value Optional.
Configuring an Ethernet subinterface
To configure an Ethernet subinterface:
Ste
p
Command Remarks
1. Enter system view. system-view N/A
2. Create an Ethernet
subinterface.
interface interface-type
interface-number.subnumber
This command also leads you to
Ethernet subinterface view.
3. Set the interface description. description text
Optional.
By default, the description of an
Ethernet subinterface is in the
format of interface-name Interface.
For example,
GigabitEthernet1/0/1.1 Interface.
4. Restore the default settings for
the subinterface. default Optional.
You can configure IP- related settings on an Ethernet subinterface. For more information, see Layer 3—IP
Services Configuration Guide.
To use an Ethernet subinterface to transmit and receive packets, you must associate it with a VLAN. For
more information, see Layer 2—LAN Switching Configuration Guide.
For the local and remote Ethernet subinterfaces to transmit traffic correctly, assign them to the same
VLAN.
Shutting down an Ethernet interface or subinterface
CAUTION:
Use this command with caution. After you manually shut down an Ethernet interface, the Ethernet interface
cannot forward packets even if it is physically connected.
You might need to shut down and then bring up an Ethernet interface or subinterface to activate some
configuration changes, for example, the speed or duplex mode changes.
To shut down an Ethernet interface or subinterface:
Ste
p
Command Remarks
1. Enter system view. system-view N/A

5
Ste
p
Command Remarks
2. Enter Ethernet interface
or subinterface view, or
port group view.
•Enter Ethernet interface view:
interface interface-type
interface-number
•Enter port group view:
port-group manual
port-group-name
•Enter Ethernet subinterface view:
interface interface-type
interface-number.subnumber
Use one of the commands.
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.
3. Shut down the Ethernet
interface or subinterface. shutdown By default, Ethernet interfaces and
subinterfaces are up.
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 physical
layer changes only when the suppression interval expires.
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. Set a physical state change
suppression interval. link-delay delay-time By default, physical state change
suppression is disabled.
Configuring loopback testing on an Ethernet interface
If an Ethernet interface does not work correctly, you can enable loopback testing on it to identify the
problem. An Ethernet interface in a loopback test does not forward data traffic.
Loopback testing has the following types:
•Internal loopback testing—Tests all on-chip functions related to Ethernet interfaces.
•External loopback testing—Tests hardware of Ethernet interfaces. To perform external loopback
testing on an Ethernet interface, connect a loopback plug to the Ethernet interface. The device sends
test packets out of the interface, which are expected to loop over the plug and back to the interface.
If the interface fails to receive any test packets, the hardware of the interface is faulty.

6
Configuration restrictions and guidelines
•On an interface that is physically down, you can only perform internal loopback testing. On an
interface administratively shut down, you cannot perform internal or external loopback testing.
•The speed, duplex, mdi, and shutdown commands are not available during loopback testing.
•During loopback testing, the Ethernet interface operates in full duplex mode. When you disable
loopback testing, the port returns to its duplex setting.
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. Enable loopback testing. loopback { external | internal } By default, loopback testing is
disabled.
Configuring the link mode of an Ethernet interface
This feature is supported on only routers configured with SAP modules.
Depending on the hardware structure of interface cards, for a device, some interfaces can operate only
as Layer 2 Ethernet interfaces (in bridge mode), some can operate only as Layer 3 Ethernet interfaces (in
route mode), but others can operate either as Layer 2 or Layer 3 Ethernet interfaces (you can set the link
mode to bridge or route).
You can configure the link mode in system view or in Ethernet interface view, which produces the same
result. The link mode configuration in system view applies to multiple interfaces, and the link mode
configuration in interface view applies only to the current interface.
Configuration restrictions and guidelines
•Before you change the link mode of an Ethernet interface, make sure the other commands have
been successfully configured. When the link mode of an Ethernet interface is being changed, you
cannot perform any other configuration.
•After you change the link mode of an Ethernet interface, all settings of the Ethernet interface are
restored to their defaults under the new link mode.
•The link mode configuration for an Ethernet interface in system view and in interface view
supersedes each other.
•You can change the link mode of only the active port of a combo interface. To activate the other port,
make sure the active port operates in bridge mode and activate the other port with the undo
shutdown command.
Configuration procedure
To change the link mode of the specified Ethernet interfaces in system view:
Step Command
1. Enter system view. system-view

7
Step Command
2. Change the link mode of the specified
Ethernet interfaces. port link-mode { bridge | route } interface-list
To change the link mode of an Ethernet interface:
Step Command
1. Enter system view. system-view
2. Enter Ethernet interface view. interface interface-type interface-number
3. Change the link mode of the Ethernet
interface. port link-mode { bridge | route }
Setting a statistics polling interval
You can configure an interface statistics polling interval. To display the interface statistics collected in the
last polling interval, use the display interface or display counters rate command. To clear the interface
statistics of an interface, use the reset counters interface command.
To set the statistics polling interval:
Step Command Remarks
1. Enter system view. system-view N/A
2. Set the statistics polling
interval. flow-interval interval
The default setting is 300
seconds.
When a large amount of
logical interfaces are
configured on the router, the
default setting is
recommended.
Enabling subinterface rate statistics collection on an Ethernet
interface
CAUTION:
Use this function with caution, because it might consume a large amount of system resources.
After you enable subinterface rate statistics collection on an Ethernet interface, the device periodically
refreshes the rate statistics on the subinterfaces of this Ethernet interface. You can use the display
interface command to view the rate statistics.
To enable subinterface rate statistics collection on an Ethernet interface:
Step Command Remarks
1. Enter system view. system-view N/A

8
Step Command Remarks
2. Enter Ethernet interface view. interface interface-type
interface-number N/A
3. Enable subinterface rate
statistics collection on the
Ethernet interface.
sub-interface rate-statistic By default, subinterface rate
statistics collection is disabled.
Configuring a Layer 2 Ethernet interface
The features in this section are supported on only SAP modules that are operating in bridge mode.
Layer 2 Ethernet interface configuration task list
You can perform the following configurations on Ethernet interfaces operating in bridge mode.
Task Remarks
Configuring a port group Optional.
Applicable to Layer 2 Ethernet interfaces.
Setting speed options for auto negotiation on an Ethernet
interface
Optional.
Applicable to FE or GE Layer 2 Ethernet
interfaces.
Configuring storm suppression Optional.
Applicable to Layer 2 Ethernet interfaces.
Configuring jumbo frame support Optional.
Applicable to Layer 2 Ethernet interfaces.
Enabling loopback detection on an Ethernet interface Optional.
Applicable to Layer 2 Ethernet interfaces.
Setting the MDI mode of an Ethernet interface Optional.
Applicable to Layer 2 Ethernet interfaces.
Testing the cable connection of an Ethernet interface Optional.
Applicable to Layer 2 Ethernet interfaces.
Configuring storm control on an Ethernet interface Optional.
Applicable to Layer 2 Ethernet interfaces.
Configuring a 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 member ports of the
group. For example, you can configure a traffic suppression threshold (see "Configuring storm
suppression") for multiple interfaces in bulk by assigning these interfaces to a port group.

9
Even though the settings are made on the port group, they are saved on each interface basis rather than
on a port group basis. You can only view the settings in the view of each interface by using 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 N/A
3. Assign Ethernet interfaces
to the manual port group. group-member interface-list
If you use the group-member
interface-type interface-start-number to
interface-type interface-end-number
command to add multiple ports in batch
to the specified port group, make sure all
these ports are of the same type and on
the same interface card, and the
interface-end-number argument must be
greater than the interface-start-number
argument.
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 that
both ends support by default. You can narrow down the speed option list for negotiation.
Figure 1 Speed auto negotiation application scenario
As shown in Figure 1, all ports on the device are operating in speed auto negotiation mode, with the
highest speed of 1000 Mbps. If the transmission rate of each server in the server cluster is 1000 Mbps,
their total transmission rate exceeds the capability of port GigabitEthernet 1/0/4, the port providing
access to the Internet for the servers.
To avoid congestion on GigabitEthernet 1/0/4, set 100 Mbps as the only option available for speed
negotiation on port GigabitEthernet 1/0/1, GigabitEthernet 1/0/2, and GigabitEthernet 1/0/3. As a
result, the transmission rate on each port connected to a server is limited to 100 Mbps.
IP network
Server 1 Server 3Server 2
( Speed 1000 Mbps ) ( Speed 1000 Mbps )
GE1/0/1
GE1/0/2
GE1/0/3
GE1/0/4
( Speed 1000 Mbps )

10
To set speed options for auto negotiation on an Ethernet interface:
Step Command
1. Enter system view. system-view
2. Enter Ethernet interface view. interface interface-type interface-number
3. Set speed options for auto negotiation. speed auto { 10 | 100 | 1000 } *
This function is available only for 100-Mbps or 1000-Mbps Layer 2 Ethernet interfaces that support
speed auto negotiation. Only the copper combo ports support this function.
The speed and speed auto commands supersede each other, and whichever is configured last takes
effect.
Configuring storm suppression
You can use the storm suppression function to limit the size of a particular type of traffic (broadcast,
multicast, or unknown unicast traffic) that can be received on a per-interface basis in Ethernet interface
view.
In interface or port group view, you set the maximum size of broadcast, multicast or unknown unicast
traffic allowed to be received on an interface or each interface in a port group. When the broadcast,
multicast, or unknown unicast traffic received on the interface exceeds this threshold, the system discards
packets until the traffic drops below this threshold.
Configuration restrictions and guidelines
•The storm suppression thresholds configured for an Ethernet interface might become invalid if you
enable the storm control function for the interface. For information about the storm control function,
see "Configuring storm control on an Ethernet interface."
•For an Ethernet interface that belongs to a port group, if you set a traffic suppression threshold for
the interface in both Ethernet interface view and port group view, the threshold configured last takes
effect.
Configuration procedure
To set storm suppression thresholds on one or multiple Ethernet interfaces:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter Ethernet interface view
or port group view.
•Enter Ethernet interface view:
interface interface-type
interface-number
•Enter port group view:
port-group manual
port-group-name
Use one of the commands.
To configure storm suppression on
an Ethernet interface, enter
Ethernet interface view.
To configure storm suppression on
a group of Ethernet interfaces,
enter port group view.
3. Set the broadcast suppression
threshold ratio.
broadcast-suppression { ratio |
pps max-pps | kbps max-kbps }
Optional.
By default, broadcast traffic is
allowed to pass through an
interface.

11
Step Command Remarks
4. Set the multicast suppression
threshold ratio.
multicast-suppression { ratio |pps
max-pps | kbps max-kbps }
Optional.
By default, multicast traffic is
allowed to pass through an
interface.
5. Set the unknown unicast
suppression threshold ratio.
unicast-suppression { ratio |pps
max-pps | kbps max-kbps }
Optional.
By default, unknown unicast traffic
is allowed to pass through an
interface.
Configuring jumbo frame support
An Ethernet interface might receive some frames larger than the standard Ethernet frame size (called
"jumbo frames") during high-throughput data exchanges such as file transfers. Usually, an Ethernet
interface discards jumbo frames. With jumbo frame support enabled, the interface can process frames
larger than the standard Ethernet frame size yet within the specified range.
In interface configuration mode (Ethernet interface view or port group view), you can set the length of
jumbo frames that are allowed to pass through Ethernet interfaces, as follows:
•If you execute the command in Ethernet interface view, the configuration takes effect only on the
interface.
•If you execute the command in port group view, the configuration takes effect on all ports in the port
group.
To configure jumbo frame support in interface view or port group view:
Step Command Remarks
1. Enter system view. system-view N/A
2. Configure jumbo frame
support.
•(Method 1) In port group
view:
a. port-group manual
port-group-name
b. jumboframe enable
[ value ]
•(Method 2) In Ethernet
interface view:
c. interface interface-type
interface-number
d. jumboframe enable
[ value ]
Use one of the methods.
By default, the device allows jumbo
frames within the specified length to
pass through all Layer 2 Ethernet
interfaces.
Enabling loopback detection on an Ethernet interface
If a device receives a packet that it sent, a loop has occurred to the device. Loops might cause broadcast
storms, which degrade network performance. You can use this feature to detect whether a loop has
occurred.
Single-port loopback occurs when an interface receives a packet that it sent and the receiving interface
is the same as the sending interface, as shown in Figure 2.

12
Figure 2 Single-port loopback
Figure 3 Multi-port loopback
You can enable loopback detection to detect loops on an interface and, if the interface supports the
loopback-detection action command, configure the protective action to take on the receiving interface
when a loop is detected, for example, to shut down the interface. Depending on whether a protective
action is configured, the device takes the actions in Table 1 to alleviate the impact of the loop condition.
Table 1 Actions to take upon detection of a loop condition
Port type Actions
No
p
rotective action is confi
g
ured A
p
rotective action is confi
g
ured
Access port
•Place the receiving interface in controlled
mode. The interface discards all incoming
packets, but still forwards outgoing packets.
•Generate traps.
•Delete all MAC address entries of the
interface.
•Perform the configured protective
action.
•Generate traps and log messages.
•Delete all MAC address entries of the
interface.
Hybrid or trunk
port
•Generate traps.
•If loopback detection control is enabled,
place the receiving interface in controlled
mode. The interface discards all incoming
packets, but still forwards outgoing packets.
•Delete all MAC address entries of the
interface.
•Create traps and log messages.
•If loopback detection control is
enabled, take the configured
protective action on the interface.
•Delete all MAC address entries of the
interface.
Configuration restrictions and guidelines
•To use loopback detection on an Ethernet interface, you must enable the function both globally and
on the interface.
•To disable loopback detection on all interfaces, run the undo loopback-detection enable command
in system view.

13
•To enable a hybrid or trunk port to take the administratively specified protective action, you must use
the loopback-detection control enable command on the port.
•When you change the link type of an Ethernet interface by using the port link-type command, the
switch removes the protective action configured on the interface. For more information about the
port link-type command, see Layer 2—LAN Switching Command Reference.
Configuration procedure
To configure loopback detection:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enable global loopback
detection. loopback-detection enable By default, global loopback
detection is disabled.
3. Enable multi-port loopback
detection.
loopback-detection
multi-port-mode enable
Optional.
By default, multi-port loopback
detection is disabled, and the
router can detect only single-port
loops.
4. Set the loopback detection
interval.
loopback-detection interval-time
time
Optional.
The default setting is 30 seconds.
5. Enter Ethernet interface view
or port group view.
•Enter Ethernet interface view:
interface interface-type
interface-number
•Enter port group view:
port-group manual
port-group-name
Use one of the commands.
To configure loopback detection
on one interface, enter Ethernet
interface view.
To configure loopback detection
on a group of Ethernet interfaces,
enter port group view.
6. Enable loopback detection on
the interface. loopback-detection enable By default, loopback detection is
disabled.
7. Enable loopback detection
control on a trunk port or a
hybrid port.
loopback-detection control enable
Optional.
By default, loopback detection
control is disabled.
8. Enable loopback detection in
all VLANs on the trunk or
hybrid port.
loopback-detection per-vlan
enable
Optional.
By default, a trunk or hybrid port
performs loopback detection only
in its PVID.
9. Set the protective action to
take on the interface when a
loop is detected.
loopback-detection action
{ no-learning |semi-block |
shutdown }
Optional.
By default, when a loop is detected
on an interface, the interface does
not forward any data packet.
With the shutdown keyword
specified, the looped port is
automatically shut down and its
physical state changes to Loop
down. After the loop is removed,
use the undo shutdown command
on the port to recover its
forwarding capability.

14
Setting the MDI mode of an Ethernet interface
IMPORTANT:
Fiber ports do not support the MDI mode setting.
You can use both crossover and straight-through Ethernet cables to connect copper Ethernet interfaces.
To accommodate these types of cables, a copper Ethernet interface can operate in one of the following
Medium Dependent Interface (MDI) modes:
•Across mode
•Normal mode
•Auto mode
A copper Ethernet interface uses an RJ-45 connector, which comprises eight pins, each of which plays a
dedicated role. For example, pins 1 and 2 transmit signals, and pins 3 and 6 receive signals. The pin
role varies by the MDI modes as follows:
•In normal mode, pins 1 and 2 are transmit pins, and pins 3 and 6 are receive pins.
•In across mode, pins 1 and 2 are receive pins, and pins 3 and 6 are transmit pins.
•In auto mode, the interface negotiates pin roles with its peer.
To enable the interface to communicate with its peer, make sure its transmit pins are connected to the
remote receive pins. If the interface can detect the connection cable type, set the interface in auto MDI
mode. If not, set its MDI mode by using the following guidelines:
•When a straight-through cable is used, set the interface to operate in the MDI mode different than
its peer.
•When a crossover cable is used, set the interface to operate in the same MDI mode as its peer, or
set either end to operate in auto mode.
To set the MDI mode of an Ethernet interface:
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. Set the MDI mode of the
Ethernet interface. mdi {across |auto |normal }
By default, a copper Ethernet
interface operates in auto mode to
negotiate pin roles with its peer.
Testing the cable connection of an Ethernet interface
IMPORTANT:
•Fiber ports do not support this feature.
•If the link of an Ethernet port is up, testin
g
its cable connection will cause the link to come down and then
go up.

15
You can test the cable connection of an Ethernet interface for a short or open circuit. The device displays
cable test results within 5 seconds. If any fault is detected, the test results include the length of the faulty
cable segment.
To test the cable connection of an Ethernet interface:
Step Command
1. Enter system view. system-view
2. Enter Ethernet interface view. interface interface-type interface-number
3. Test the cable connected to the Ethernet interface.
virtual-cable-test
Configuring storm control on an Ethernet interface
Storm control compares broadcast, multicast, and unknown unicast traffic regularly with their respective
traffic thresholds on an Ethernet interface. For each type of traffic, storm control provides a lower
threshold and a higher threshold.
For management purposes, you can configure the interface to send threshold event traps and log
messages when monitored traffic exceeds the upper threshold or falls below the lower threshold from the
upper threshold.
Depending on your configuration, when a particular type of traffic exceeds its upper threshold, the
interface does either of the following:
•Blocks this type of traffic, while forwarding other types of traffic. Even though the interface does not
forward the blocked traffic, it still counts the traffic. When the blocked traffic drops below the lower
threshold, the port begins to forward the traffic.
•Shuts down automatically. The interface shuts down automatically and stops forwarding any traffic.
When the blocked traffic is detected dropping below the lower threshold, the port does not forward
the traffic. To bring up the interface, use the undo shutdown command or disable the storm control
function.
Alternatively, you can configure the storm suppression function to control a specific type of traffic. Do not
enable them both on an Ethernet interface at the same time because the storm suppression and storm
control functions are mutually exclusive. For example, with an unknown unicast suppression threshold set
on an Ethernet interface, do not enable storm control for unknown unicast traffic on the interface. For
more information about storm suppression, see "Configuring storm suppression."
Configuration guidelines
•For network stability, use the default or set a higher traffic polling interval.
•Storm control uses a complete polling cycle to collect traffic data, and analyzes the data in the next
cycle. An interface takes one to two polling intervals to take a storm control action.
•The storm control function allows you to set the upper and lower thresholds for all three types of
packets separately on the same interface.
Configuration procedure
To configure storm control on an Ethernet interface:
Ste
p
Command Remarks
1. Enter system view. system-view N/A