Contents

Configuring Ethernet interfaces· 1

About Ethernet interface· 1

Configuring common Ethernet interface settings· 1

Configuring basic settings of an Ethernet interface· 1

Configuring basic settings of an Ethernet subinterface· 1

Configuring jumbo frame support 2

Configuring dampening on an Ethernet interface· 2

Setting the statistics polling interval 4

Enabling subinterface rate statistics collection on an Ethernet interface· 4

Restoring the default settings for an interface· 5

Configuring a Layer 3 Ethernet interface or subinterface· 5

Setting the MTU for an Ethernet interface or subinterface· 5

Setting the MAC address of an Ethernet interface· 6

Enabling statistics collection on a Layer 3 Ethernet subinterface· 6

Display and maintenance commands· 6

 

 

Configuring Ethernet interfaces

About Ethernet interface

This chapter describes how to configure Ethernet interfaces.

 

Configuring common Ethernet interface settings

Configuring basic settings of an Ethernet interface

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Set the description for the Ethernet interface.

description text

The default setting is interface-name Interface. For example, GigabitEthernet1/0 Interface.

4.     Set the expected bandwidth for the Ethernet interface.

bandwidth bandwidth-value

By default, the expected bandwidth (in kbps) is the interface baud rate divided by 1000.

5.     Bring up the Ethernet interface.

undo shutdown

By default, an Ethernet interface is up.

Configuring basic settings of an Ethernet subinterface

Restrictions and guidelines for Ethernet subinterface basic settings

·     To transmit and receive packets through an Ethernet subinterface, you must associate it with a VLAN. For more information, see VLAN termination configuration in Layer 2—LAN Switching Configuration Guide.

·     To transmit packets between a local Ethernet subinterface and a remote Ethernet subinterface, configure them with the same subinterface number and VLAN ID.

·     Before creating a Layer 3 Ethernet subinterface, do not reserve a resource for the VLAN interface whose interface number is the subinterface number. After you reserve a VLAN interface resource, do not create a Layer 3 Ethernet subinterface whose subinterface number is the VLAN interface number. A Layer 3 Ethernet subinterface uses the VLAN interface resource in processing tagged packets whose VLAN ID matches the subinterface number. For more information about reserving resources for VLAN interfaces, see Layer 2—LAN Switching Configuration Guide.

Procedure

1.     Enter system view.

system-view

2.     Create an Ethernet subinterface.

interface interface-type interface-number.subnumber

3.     Set the description for the Ethernet subinterface.

description text

The default setting is interface-name Interface. For example, GigabitEthernet1/0.1 Interface.

4.     Set the expected bandwidth for the Ethernet subinterface.

bandwidth bandwidth-value

By default, the expected bandwidth (in kbps) is the interface baud rate divided by 1000.

5.     Bring up the Ethernet subinterface.

undo shutdown

By default, an Ethernet subinterface is up.

Configuring jumbo frame support

About this task

Jumbo frames are frames larger than a device-specific size and are typically received by an Ethernet interface during high-throughput data exchanges, such as file transfers.

The Ethernet interface processes jumbo frames in the following ways:

·     When the Ethernet interface is configured to deny jumbo frames (by using the undo jumboframe enable command), the Ethernet interface discards jumbo frames.

·     When the Ethernet interface is configured with jumbo frame support, the Ethernet interface performs the following operations:

¡     Processes jumbo frames within the specified length.

¡     Discards jumbo frames that exceed the specified length.

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Configure jumbo frame support.

jumboframe enable [ size ]

By default, the device allows jumbo frames within the specified length to pass through. For more information, see Interface Command Reference.

If you set the size argument multiple times, the most recent configuration takes effect.

Configuring dampening on an Ethernet interface

About this task

The interface dampening feature uses an exponential decay mechanism to prevent excessive interface flapping events from adversely affecting routing protocols and routing tables in the network. Suppressing interface state change events protects the system resources.

If an interface is not dampened, its state changes are reported. For each state change, the system also generates an SNMP trap and log message.

After a flapping interface is dampened, it does not report its state changes to the CPU. For state change events, the interface only generates SNMP trap and log messages.

Parameters

·     Penalty—The interface has an initial penalty of 0. When the interface flaps, the penalty increases by 1000 for each down event until the ceiling is reached. It does not increase for up events. When the interface stops flapping, the penalty decreases by half each time the half-life timer expires until the penalty drops to the reuse threshold.

·     Ceiling—The penalty stops increasing when it reaches the ceiling.

·     Suppress-limit—The accumulated penalty that triggers the device to dampen the interface. In dampened state, the interface does not report its state changes to the CPU. For state change events, the interface only generates SNMP traps and log messages.

·     Reuse-limit—When the accumulated penalty decreases to this reuse threshold, the interface is not dampened. Interface state changes are reported to the upper layers. For each state change, the system also generates an SNMP trap and log message.

·     Decay—The amount of time (in seconds) after which a penalty is decreased.

·     Max-suppress-time—The maximum amount of time the interface can be dampened. If the penalty is still higher than the reuse threshold when this timer expires, the penalty stops increasing for down events. The penalty starts to decrease until it drops below the reuse threshold.

When configuring the dampening command, follow these rules to set the values mentioned above:

·     The ceiling is equal to 2(Max-suppress-time/Decay)  × reuse-limit. It is not user configurable.

·     The configured suppress limit is lower than or equal to the ceiling.

·     The ceiling is lower than or equal to the maximum suppress limit supported.

Figure 1 shows the change rule of the penalty value. The lines t0 and t2 indicate the start time and end time of the suppression, respectively. The period from t0 to t2 indicates the suppression period, t0 to t1 indicates the max-suppress-time, and t1 to t2 indicates the complete decay period.

Figure 1 Change rule of the penalty value

‌

Restrictions and guidelines

·     The dampening command does not take effect on the administratively down events. When you execute the shutdown command, the penalty restores to 0, and the interface reports the down event to the upper-layer protocols.

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Enable dampening on the interface.

dampening [ half-life reuse suppress max-suppress-time ]

By default, interface dampening is disabled on Ethernet interfaces.

Setting the statistics polling interval

About this task

To display the interface statistics collected in the last statistics polling interval, use the display interface command. To clear the interface statistics, use the reset counters interface command.

Restrictions and guidelines for setting the statistics polling interval

·     As a best practice, use the default setting when you set the statistics polling interval in system view. A short statistics polling interval might decrease the system performance and result in inaccurate statistics.

Setting the statistics polling interval in system view

1.     Enter system view.

system-view

2.     Set the statistics polling interval.

flow-interval interval

By default, the statistics polling interval is 300 seconds.

Enabling subinterface rate statistics collection on an Ethernet interface

Restrictions and guidelines

This feature is resource intensive. When you use this feature, make sure you fully understand its impact on system performance.

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.

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Enable subinterface rate statistics collection on the Ethernet interface.

sub-interface rate-statistic

By default, subinterface rate statistics collection is disabled on an Ethernet interface.

4.     (Optional.) View the subinterface rate statistics.

display interface

Restoring the default settings for an interface

Restrictions and guidelines

	CAUTION: This feature might interrupt ongoing network services. Make sure you are fully aware of the impacts of this feature when you use it in a live network.

‌

This feature might fail to restore the default settings for some commands because of command dependencies or system restrictions. You can use the display this command in interface view to check for these commands and perform their undo forms or follow the command reference to restore their default settings. If your restoration attempt still fails, follow the error message to resolve the problem.

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view or Ethernet subinterface view.

interface interface-type { interface-number | interface-number.subnumber }

3.     Restore the default settings for the interface.

default

Configuring a Layer 3 Ethernet interface or subinterface

Setting the MTU for an Ethernet interface or subinterface

Restrictions and guidelines

The maximum transmission unit (MTU) of an Ethernet interface affects the fragmentation and reassembly of IP packets on the interface. Typically, you do not need to modify the MTU of an interface.

Procedure

1.     Enter system view.

system-view

2.     Enter interface view.

interface interface-type { interface-number | interface-number.subnumber }

3.     Set the interface MTU.

mtu size

The default setting is 1500 bytes.

Setting the MAC address of an Ethernet interface

About this task

In a network, when the Layer 3 Ethernet interfaces of different devices have the same MAC address, the devices might fail to communicate correctly. To eliminate the MAC address conflicts, use the mac-address command to modify the MAC addresses of Layer 3 Ethernet interfaces.

Procedure

1.     Enter system view.

system-view

2.     Enter interface view.

interface interface-type interface-number

3.     Set the interface MAC address.

mac-address mac-address

By default, no MAC address is set for a Layer 3 Ethernet interface.

Enabling statistics collection on a Layer 3 Ethernet subinterface

About this task

This feature is resource intensive. When you use this feature, make sure you fully understand its impact on system performance.

Procedure

1.     Enter system view.

system-view

2.     Enter Layer 3 Ethernet subinterface view.

interface interface-type interface-number.subnumber

3.     Enable statistics collection on the Layer 3 Ethernet subinterface.

traffic-statistic enable

By default, statistics collection is disabled on a Layer 3 Ethernet subinterface.

4.     (Optional.) Display the subinterface traffic statistics.

display interface

display counters

The Input and Output fields in the display interface command output display the subinterface traffic statistics.

Display and maintenance commands

Execute display commands in any view and reset commands in user view.

 

Task	Command
Display interface traffic statistics.	display counters { inbound | outbound } interface [ interface-type [ interface-number | interface-number.subnumber ] ]
Display traffic rate statistics of interfaces in up state over the last statistics polling interval.	display counters rate { inbound | outbound } interface [ interface-type [ interface-number | interface-number.subnumber ] ]
Display the Ethernet module statistics.	In standalone mode: display ethernet statistics In IRF mode: display ethernet statistics slot slot-number
Display the operational and status information of the specified interfaces.	display interface [ interface-type [ interface-number | interface-number.subnumber ] ] [ brief [ description | down ] ]
Display the status and packet statistics of interfaces.	display interface link-info [ main ]
Display operating status and information of all interfaces except subinterfaces.	display interface [ interface-type ] [ brief [ description | down ] ] main
Clear interface statistics.	reset counters interface [ interface-type [ interface-number | interface-number.subnumber ] ]
Clear the Ethernet module statistics.	In standalone mode: reset ethernet statistics In IRF mode: reset ethernet statistics [ slot slot-number ]

‌