The Switch Series supports Ethernet interfaces, management Ethernet interfaces, Console interfaces, and USB interfaces. For the interface types and the number of interfaces supported by a switch model, see the hardware manuals.

This chapter describes how to configure management Ethernet interfaces and Ethernet interfaces.

Configuring a management Ethernet interface

About this task

You can connect a management Ethernet interface to a PC for software loading and system debugging, or connect it to a remote NMS for remote system management.

Procedure

1. Enter system view.

system-view

2. Enter management Ethernet interface view.

interface M-GigabitEthernet interface-number

3. (Optional.) Set the interface description.

description text

The default setting is M-GigabitEthernet0/0/0 Interface.

4. (Optional.) Set the duplex mode for the management Ethernet interface.

duplex { auto | full | half }

By default, the duplex mode is auto for a management Ethernet interface.

5. (Optional.)_Set the speed for the management Ethernet interface.

speed { 10 | 100 | 1000 | auto }

By default, the speed is auto for a management Ethernet interface.

6. (Optional.) Shut down the interface.

shutdown

By default, the management Ethernet interface is up.

CAUTION:

Executing the shutdown command on an interface will disconnect the link of the interface and interrupt communication. Use this command with caution.

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Ethernet interface naming conventions

The Ethernet interfaces are named in the format of interface type A/B/C. The letters that follow the interface type represent the following elements:

· A—Device ID, which is fixed at 1.

· B—Card slot number.

· C—Port index.

Restrictions and guidelines: Ethernet interface configuration

Changing the link type of an Ethernet interface, splitting an interface, or combining breakout interfaces can cause temporary packet loss on the device if the following data buffer configuration exists on the device:

· buffer egress cell queue shared (setting the maximum size of the shared area that the queue can use)

· buffer service-pool shared (setting the size of the shared area that the service pool can use)

For more information about data buffer configuration, see ACL and QoS Configuration Guide.

Configuring common Ethernet interface settings

This section describes the settings common to Layer 2 Ethernet interfaces, Layer 3 Ethernet interfaces, and Layer 3 Ethernet subinterfaces. For more information about the settings specific to Layer 2 Ethernet interfaces, see "Configuring a Layer 2 Ethernet interface." For more information about the settings specific to Layer 3 Ethernet interfaces or subinterfaces, see "Configuring a Layer 3 Ethernet interface or subinterface."

Splitting a 400-GE interface and combining 200-GE breakout interfaces

About this task

You can use a 400-GE interface as a single interface. To improve port density, reduce costs, and improve network flexibility, you can also split a 400-GE interface into two 200-GE breakout interfaces. The 200-GE breakout interfaces support the same configuration and attributes as common 200-GE interfaces, except that they are numbered differently.

For example, you can split 400-GE interface FourHundredGigE 1/0/1 into two 200-GE breakout interfaces TwoHundredGigE 1/0/1:1 and TwoHundredGigE 1/0/1:2.

If you need higher bandwidth on a single interface, you can combine the two 200-GE breakout interfaces into a 400-GE interface.

Restrictions and guidelines for 400-GE interface splitting and 200-GE breakout interface combining

· After configuring this feature, you do not need to reboot the device. To view the breakout interfaces, execute the display interface brief command.

Splitting a 400-GE interface into two 200-GE breakout interfaces

1. Enter system view.

system-view

2. Enter 400-GE interface view.

interface fourhundredgige interface-number

3. Split the 400-GE interface into two 200-GE breakout interfaces.

using twohundredgige

By default, a 400-GE interface is not split and operates as a single interface.

Combining two 200-GE breakout interfaces into a 400-GE interface

1. Enter system view.

system-view

2. Enter the view of any 200-GE breakout interface.

interface twohundredgige interface-number

3. Combine the two 200-GE breakout interfaces into a 400-GE interface.

using fourhundredgige

By default, a 200-GE breakout interface operates as a single interface.

Configuring basic settings of an Ethernet interface

About this task

You can configure an Ethernet interface to operate in one of the following duplex modes:

· Full-duplex mode—The interface can send and receive packets simultaneously.

· Autonegotiation mode—The interface negotiates a duplex mode with its peer.

You can set the speed of an Ethernet interface or enable it to automatically negotiate a speed with its peer.

Restrictions and guidelines

The shutdown, port up-mode, and loopback commands are mutually exclusive.

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, HundredGigE1/1/1 Interface.

4. Set the duplex mode for the Ethernet interface.

duplex { auto | full }

By default, the duplex mode is auto for Ethernet interfaces.

5. Set the speed for the Ethernet interface.

speed { 40000 | 100000 | 200000 | 400000 | auto }

By default, an Ethernet interface negotiates a speed with its peer.

6. Set the expected bandwidth for the Ethernet interface.

bandwidth bandwidth-value

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

7. Bring up the Ethernet interface.

undo shutdown

By default, Ethernet interfaces are in up state.

Configuring basic settings of an Ethernet subinterface

About this task

By default, a Layer 3 Ethernet subinterface processes packets for only the VLAN whose ID is the same as the subinterface number.

Restrictions and guidelines for Ethernet subinterface basic settings

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, HundredGigE1/1/1.1 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, Ethernet subinterfaces are in up state.

Configuring the link mode of an Ethernet interface

About this task

Interfaces on the device can operate either as Layer 2 or Layer 3 Ethernet interfaces. You can use commands to set the link mode to bridge or route.

Restrictions and guidelines

Procedure

1. Enter system view.

system-view

2. Enter Ethernet interface view.

interface interface-type interface-number

3. Configure the link mode of the Ethernet interface.

port link-mode { bridge | route }

By default, all Ethernet interfaces on the device operate in bridge mode.

CAUTION:

After you change the link mode of an Ethernet interface, all commands (except the description, duplex, jumboframe enable, speed, shutdown commands) on the Ethernet interface are restored to their defaults in the new link mode.

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Configuring jumbo frame support

About this task

Jumbo frames are frames larger than 1536 bytes 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 9416 bytes to pass through.

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

Configuring physical state change suppression on an Ethernet interface

About this task

The physical link state of an Ethernet interface is either up or down. Each time the physical link of an interface comes up or goes down, the interface immediately reports the change to the CPU. The CPU then performs the following operations:

· Notifies the upper-layer protocol modules (such as routing and forwarding modules) of the change for guiding packet forwarding.

· Automatically generates traps and logs to inform users to take the correct actions.

To prevent frequent physical link flapping from affecting system performance, configure physical state change suppression. You can configure this feature to suppress only link-down events, only link-up events, or both. If an event of the specified type still exists when the suppression interval expires, the system reports the event to the CPU.

Restrictions and guidelines

Do not enable this feature on an interface that has RRPP, spanning tree protocols, or Smart Link enabled.

You can configure different suppression intervals for link-up and link-down events.

If you execute the link-delay command multiple times on an interface, the following rules apply:

· You can configure the suppression intervals for link-up and link-down events separately.

· If you configure the suppression interval multiple times for link-up or link-down events, the most recent configuration takes effect.

The link-delay, dampening, and port link-flap protect enable commands are mutually exclusive on an Ethernet interface.

Procedure

1. Enter system view.

system-view

2. Enter Ethernet interface view.

interface interface-type interface-number

3. Configure physical state change suppression.

link-delay { down | up } [ msec ] delay-time

By default, each time the physical link of an interface goes up or comes down, the interface immediately reports the change to the CPU.

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

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Restrictions and guidelines

· The dampening, link-delay, and port link-flap protect enable commands are mutually exclusive on an interface.

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

· Do not enable the dampening feature on an interface with RRPP, MSTP, or Smart Link enabled.

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.

Enabling link flapping protection on an interface

About this task

Link flapping on an interface changes network topology and increases the system overhead. For example, in an active/standby link scenario, when interface status on the active link changes between UP and DOWN, traffic switches between active and standby links. To solve this problem, configure this feature on the interface.

With this feature enabled on an interface, when the interface goes down, the system enables link flapping detection. During the link flapping detection interval, if the number of detected flaps reaches or exceeds the link flapping detection threshold, the system shuts down the interface.

Restrictions and guidelines

This feature takes effect only if it is configured in both the system view and interface view.

When you configure this feature on an interface, how link flapping protection is triggered depends on the parameters specified:

· If you specify level-1 link flapping protection parameters but do not specify level-2 parameters, link flapping protection will be triggered and the interface will be shut down when the level-1 link flapping protection conditions are met.

· If you specify both level-1 and level-2 link flapping protection parameters, link flapping protection will be triggered and the interface will be shut down when either of level-1 and level-2 link flapping protection conditions are met.

The dampening, link-delay, and port link-flap protect enable commands are mutually exclusive on an Ethernet interface.

To bring up an interface that has been shut down by link flapping protection, execute the undo shutdown command.

In the display interface command output, the Link-Flap DOWN value of the Current state field indicates that the interface has been shut down by link flapping protection.

Procedure

1. Enter system view.

system-view

2. Enable link flapping protection globally.

link-flap protect enable

By default, link flapping protection is disabled globally.

3. Enter Ethernet interface view.

interface interface-type interface-number

4. Enable link flapping protection on the Ethernet interface.

port link-flap protect enable [ interval interval | threshold threshold ] * [ second-interval second-interval second-threshold second-threshold ]

By default, link flapping protection is disabled on an Ethernet interface.

Configuring FEC

About this task

The forward error correction (FEC) feature corrects packet errors to improve transmission quality. It attaches correction information to a packet at the sending end, and corrects error codes generated during transmission at the receiving end based on the correction information. You can set the FEC mode as needed.

Restrictions and guidelines

This feature is supported only on 100-GE interfaces.

Make sure you set the same FEC mode for both interfaces of a link.

Procedure

1. Enter system view.

system-view

2. Enter Ethernet interface view.

interface interface-type interface-number

3. Set the FEC mode of the Ethernet interface..

port fec mode { auto | none | rs-fec }

By default, the interface's FEC is in autonegotiation mode.

Enabling FEC bypass

About this task

By default, when an interface continuously receives three or more packets that it cannot process, the device will shut down and then bring up the interface to fix the interface. However, there are many possible packet error reasons. If you are sure that the interface is not faulty, you do not need to fix the interface. To avoid service interruption in this case, you can enable this feature on the interface to prevent the device from shutting down and bringing up the interface.

Restrictions and guidelines

This feature is supported only on 25-GE, 40-GE, and 100-GE interfaces.

Procedure

1. Enter system view.

system-view

2. Enter Ethernet interface view.

interface interface-type interface-number

3. Enable FEC bypass.

port fec bypass enable

By default, FEC is disabled.

Configuring generic flow control on an Ethernet interface

About this task

To avoid dropping packets on a link, you can enable generic flow control at both ends of the link. When traffic congestion occurs at the receiving end, the receiving end sends a flow control (Pause) frame to ask the sending end to suspend sending packets. Generic flow control includes the following types:

· TxRx-mode generic flow control—Enabled by using the flow-control command. With TxRx-mode generic flow control enabled, an interface can both send and receive flow control frames:

¡ When congestion occurs, the interface sends a flow control frame to its peer.

¡ When the interface receives a flow control frame from its peer, it suspends sending packets to its peer.

· Rx-mode generic flow control—Enabled by using the flow-control receive enable command. With Rx-mode generic flow control enabled, an interface can receive flow control frames, but it cannot send flow control frames:

¡ When congestion occurs, the interface cannot send flow control frames to its peer.

¡ When the interface receives a flow control frame from its peer, it suspends sending packets to its peer.

To handle unidirectional traffic congestion on a link, configure the flow-control receive enable command at one end and the flow-control command at the other end. To enable both ends of a link to handle traffic congestion, configure the flow-control command at both ends.

Restrictions and guidelines

To implement flow control, configure flow control on each interface that the traffic passes through.

Procedure

1. Enter system view.

system-view

2. Enter Ethernet interface view.

interface interface-type interface-number

3. Enable generic flow control.

¡ Enable TxRx-mode generic flow control.

flow-control

¡ Enable Rx-mode generic flow control.

flow-control receive enable

By default, generic flow control is disabled on an Ethernet interface.

Setting the statistics polling interval

About this task

By setting the statistics polling interval, you can collect statistics of packets and analyze packets at the specified interval. Based on the interface traffic statistics, you can take traffic control measures promptly to avoid network congestion and service interruption.

· When network congestion is detected, you can set the statistics polling interval to be smaller than 300 seconds (30 seconds when congestion deteriorates). Then, check traffic distribution on interfaces within a short period of time. For data packets that cause congestion, take traffic control measures.

· When the network bandwidth is sufficient and services are operating normally, you can set the statistics polling interval to be greater than 300 seconds. Once traffic parameter anomalies occur, modify the statistics polling interval promptly so that you can observe the traffic parameter trend in real time.

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.

Setting the statistics polling interval in Ethernet interface view

1. Enter system view.

system-view

2. Enter Ethernet interface view.

interface interface-type interface-number

3. Set the statistics polling interval for the Ethernet interface.

flow-interval interval

By default, the statistics polling interval is 300 seconds.

Enabling loopback testing on an Ethernet interface

About this task

Perform this task to determine whether an Ethernet link works correctly.

Loopback testing includes the following types:

· Internal loopback testing—Tests the device where the Ethernet interface resides. The Ethernet interface sends outgoing packets back to the local device. If the device fails to receive the packets, the device fails.

· External loopback testing—Tests the hardware function of the Ethernet interface. The Ethernet interface sends outgoing packets to the local device through a self-loop plug. If the device fails to receive the packets, the hardware function of the Ethernet interface fails.

Restrictions and guidelines

· After you enable this feature on an Ethernet interface, the interface does not forward data traffic.

· The shutdown, port up-mode, and loopback commands are mutually exclusive.

· After you enable this feature on an Ethernet interface, the Ethernet interface switches to full duplex mode. After you disable this feature, the Ethernet interface restores to its duplex setting.

Procedure

1. Enter system view.

system-view

2. Enter Ethernet interface view.

interface interface-type interface-number

3. Configure loopback testing on the Ethernet interface.

¡ Enable loopback testing on the Ethernet interface.

loopback{ external | internal }

By default, loopback testing is disabled on an Ethernet interface.

Forcibly bringing up a fiber port

About this task

As shown in Figure 2, a fiber port uses separate fibers for transmitting and receiving packets. The physical state of the fiber port is up only when both transmit and receive fibers are physically connected. If one of the fibers is disconnected, the fiber port does not work.

To enable a fiber port to forward traffic over a single link, you can use the port up-mode command. This command forcibly brings up a fiber port, even when no fiber links or transceiver modules are present for the fiber port. When one fiber link is present and up, the fiber port can forward packets over the link unidirectionally.

Figure 2 Forcibly bring up a fiber port

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Restrictions and guidelines

· The port up-mode, shutdown, and loopback commands are mutually exclusive.

· A fiber port does not support this feature if the port is shut down by a protocol or by using the shutdown command.

· A fiber port forcibly brought up stays physically up whether or not a transceiver module or a fiber link is present for the port.

Procedure

1. Enter system view.

system-view

2. Enter Ethernet interface view.

interface interface-type interface-number

3. Forcibly bring up the fiber port.

port up-mode

By default, a fiber port is not forcibly brought up, and the physical state of a fiber port depends on the physical state of the fibers.

Configuring interface alarm functions

About this task

With the interface alarm functions enabled, when the number of error packets on an interface in normal state within the specified interval exceeds the upper threshold, the interface generates an upper threshold exceeding alarm and enters the alarm state. When the number of error packets on an interface in the alarm state within the specified interval drops below the lower threshold, the interface generates a recovery alarm and restores to the normal state.

Restrictions and guidelines

An interface that is shut down because of error packet alarms cannot automatically recover. To bring up the interface, execute the undo shutdown command on the interface.

Enabling interface alarm functions

1. Enter system view.

system-view

2. Enable alarm functions for the interface monitoring module.

By default, all alarm functions are enabled for interfaces.

Configuring CRC error packet parameters

1. Enter system view.

system-view

2. Configure global CRC error packet alarm parameters.

ifmonitor crc-error slot slot-number high-threshold high-value low-threshold low-value interval interval [ shutdown ]

By default, the upper threshold is 1000, the lower threshold is 100, and the statistics collection and comparison interval is 10 seconds for CRC error packets.

3. Enter Ethernet interface view.

interface interface-type interface-number

4. Configure CRC error packet alarm parameters for the interface.

port ifmonitor crc-error [ ratio ] high-threshold high-value low-threshold low-value interval interval [ shutdown ]

By default, an interface uses the global CRC error packet alarm parameters.

Configuring input error packet alarm parameters

1. Enter system view.

system-view

2. Configure global input error packet alarm parameters.

ifmonitor input-error slot slot-number high-threshold high-value low-threshold low-value interval interval [ shutdown ]

By default, the upper threshold is 1000, the lower threshold is 100, and the statistics collection and comparison interval is 10 seconds for input error packets.

3. Enter Ethernet interface view.

interface interface-type interface-number

4. Configure input error packet alarm parameters for the interface.

port ifmonitor input-error high-threshold high-value low-threshold low-value interval interval [ shutdown ]

By default, an interface uses the global input error packet alarm parameters.

Configuring output error packet alarm parameters

1. Enter system view.

system-view

2. Configure global output error packet alarm parameters.

ifmonitor output-error slot slot-number high-threshold high-value low-threshold low-value interval interval [ shutdown ]

By default, the upper threshold is 1000, the lower threshold is 100, and the statistics collection and comparison interval is 10 seconds for output error packets.

3. Enter Ethernet interface view.

interface interface-type interface-number

4. Configure output error packet alarm parameters.

port ifmonitor output-error high-threshold high-value low-threshold low-value interval interval [ shutdown ]

By default, an interface uses the global output error packet alarm parameters.

Configuring input bandwidth usage alarm parameters

1. Enter system view.

system-view

2. Configure global input bandwidth usage alarm parameters.

ifmonitor input-usage slot slot-number high-threshold high-value low-threshold low-value

By default, the upper threshold is 90 and the lower threshold is 80 for input bandwidth usage alarms.

3. Enter Ethernet interface view.

interface interface-type interface-number

4. Configure input bandwidth usage alarm parameters.

port ifmonitor input-usage high-threshold high-value low-threshold low-value

By default, an interface uses the global input bandwidth usage alarm parameters.

Configuring output bandwidth usage alarm parameters

1. Enter system view.

system-view

2. Configure global output bandwidth usage alarm parameters.

ifmonitor output-usage slot slot-number high-threshold high-value low-threshold low-value

By default, the upper threshold is 90 and the lower threshold is 80 for output bandwidth usage alarms.

3. Enter Ethernet interface view.

interface interface-type interface-number

4. Configure output bandwidth usage alarm parameters.

port ifmonitor output-usage high-threshold high-value low-threshold low-value

By default, an interface uses the global output bandwidth usage alarm parameters.

Configuring received pause frame alarm parameters

1. Enter system view.

system-view

2. Configure global received pause frame alarm parameters.

ifmonitor rx-pause slot slot-number high-threshold high-value low-threshold low-value interval interval

By default, the upper threshold is 500, the lower threshold is 100, and the statistics collection and comparison interval is 10 seconds for received pause frames.

3. Enter Ethernet interface view.

interface interface-type interface-number

4. Configure received pause frame alarm parameters.

port ifmonitor rx-pause high-threshold high-value low-threshold low-value interval interval

By default, an interface uses the global received pause frame alarm parameters.

Configuring sent pause frame alarm parameters

1. Enter system view.

system-view

2. Configure global sent pause frame alarm parameters.

ifmonitor tx-pause slot slot-number high-threshold high-value low-threshold low-value interval interval [ shutdown ]

By default, the upper threshold is 500, the lower threshold is 100, and the statistics collection and comparison interval is 10 seconds for sent pause frames.

3. Enter Ethernet interface view.

interface interface-type interface-number

4. Configure sent pause frame alarm parameters.

port ifmonitor tx-pause high-threshold high-value low-threshold low-value interval interval [ shutdown ]

By default, an interface uses the global sent pause frame alarm parameters.

Shutting down all physical interfaces

About this task

This feature shuts down all physical interfaces except the management Ethernet interfaces on the device. Physical interfaces shut down by using this command are in ADM state.

Restrictions and guidelines

To shut down all physical interfaces or the specified interface, execute the shutdown all-physical-interfaces command in system view or execute the shutdown command in interface view.

To bring up interfaces shut down by using the shutdown all-physical-interfaces command, execute its undo form in system view. To bring up an interface shut down by using the shutdown command, execute its undo form in interface view.

If you execute the shutdown all-physical-interfaces command with the include irf-physical-interface keyword multiple times, this command shuts down all physical interfaces except the management Ethernet interfaces on the device.

This command does not take effect on physical interfaces that have joined a service loopback group.

Procedure

1. Enter system view.

system-view

2. Shut down all physical interfaces except management Ethernet interfaces.

shutdown all-physical-interfaces

By default, physical interfaces are up.

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.

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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 2 Ethernet interface

Configuring storm control on an Ethernet interface

About this task

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 an upper threshold.

Depending on your configuration, when a particular type of traffic exceeds its upper threshold, the interface performs either of the following operations:

· Blocks this type of traffic and forwards 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 interface begins to forward the traffic.

· Goes down automatically—The interface goes down automatically and stops forwarding any traffic. When the blocked traffic drops below the lower threshold, the interface does not automatically come up. To bring up the interface, use the undo shutdown command or disable the storm control feature.

You can configure an Ethernet interface to output threshold event traps and log messages when monitored traffic meets one of the following conditions:

· Exceeds the upper threshold.

· Drops below the lower threshold.

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.

Procedure

1. Enter system view.

system-view

2. (Optional.) Set the statistics polling interval of the storm control module.

storm-constrain interval interval

The default setting is 10 seconds.

For network stability, use the default or set a longer statistics polling interval.

3. Enter Ethernet interface view.

interface interface-type interface-number

4. Enable storm control, and set the lower and upper thresholds for broadcast, multicast, or unknown unicast traffic.

storm-constrain { broadcast | multicast | unicast } { pps | kbps | ratio } upperlimit lowerlimit

By default, storm control is disabled.

5. Set the control action to take when monitored traffic exceeds the upper threshold.

storm-constrain control { block | shutdown }

By default, storm control is disabled.

6. Enable the Ethernet interface to output log messages when it detects storm control threshold events.

storm-constrain enable log

By default, the Ethernet interface outputs log messages when monitored traffic exceeds the upper threshold or drops below the lower threshold from a value above the upper threshold.

7. Enable the Ethernet interface to send storm control threshold event traps.

storm-constrain enable trap

By default, the Ethernet interface sends traps when monitored traffic exceeds the upper threshold or drops below the lower threshold from the upper threshold from a value above the upper threshold.

Enabling bridging on an Ethernet interface

About this task

By default, the device drops packets whose outgoing interface and incoming interface are the same.

To enable the device to forward such packets rather than drop them, enable the bridging feature in Ethernet interface view.

Procedure

1. Enter system view.

system-view

2. Enter Ethernet interface view.

interface interface-type interface-number

3. Enable bridging on the Ethernet interface.

port bridge enable

By default, bridging is disabled on an Ethernet interface.

Configuring a Layer 3 Ethernet interface or subinterface

Setting the MTU for an Ethernet interface or subinterface

About this task

The maximum transmission unit (MTU) determines the maximum number of bytes in a single IP packet that can be sent. The length of an IP packet refers to the number of bytes starting from the IP header to the payload.

When the IP layer receives an IP data packet to be sent, the IP layer determines the local destination interface of the packet and obtains the MTU of the interface. The IP layer compares the MTU with the length of the data packet to be sent. If the length is greater than the MTU, the IP layer fragments the packet. The length of a fragment can be smaller than or equal to the MTU to ensure that big packets are not lost on the network.

As a best practice, use the default MTU. When the packet length or the packet receiver changes, you can adjust the MTU as needed. When configuring the MTU, follow these restrictions and guidelines:

· If the configured MTU is small but the packet length is large, the following events might occur:

¡ Packets will be dropped when they are forwarded by hardware.

¡ Packets will be fragmented into too many fragments when packets are forwarded through the CPUs, which affects normal data transmission.

· If the configured MTU is too large, the MTU will exceed the receiving capabilities of the receiver or a device along the transmission path. As a result, packets will be fragmented or even dropped, which increases the network transmission load and affects data transmission.

Restrictions and guidelines

The 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 MTU for the interface.

mtu size

The default setting is 1500 bytes.

Setting the MAC address of an Ethernet interface or subinterface

About this task

In a network, when the Layer 3 Ethernet interfaces or subinterfaces 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 or subinterfaces.

Procedure

1. Enter system view.

system-view

2. Enter interface view.

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

3. Set the interface MAC address.

mac-address mac-address

By default, no MAC address is set for an Ethernet interface.

As a best practice, do not set a MAC address in the VRRP-reserved MAC address range for a Layer 3 Ethernet subinterface.

Display and maintenance commands for Ethernet interfaces

For more information about the display diagnostic-information command, see device management in Fundamentals Command Reference.

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 operating information for the IFMGR module.	display diagnostic-information ifmgr [ key-info ] [ filename ]
Display the Ethernet module statistics.	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 the operational and status information of interfaces except subinterfaces.	display interface [ interface-type ] [ brief [ description \| down ] ] main
Display information about link flapping protection on interfaces.	display link-flap protection [ interface interface-type [ interface-number ] ]
Display the physical link state change statistics of interfaces.	display link-state-change statistics interface [ interface-type [ interface-number ] ]
Display information about dropped packets on the specified interfaces.	display packet-drop { interface [ interface-type [ interface-number ] ] \| summary }
Display information about storm control on the specified interfaces.	display storm-constrain [ broadcast \| multicast \| unicast ] [ interface interface-type interface-number ]
Clear interface statistics.	reset counters interface [ interface-type [ interface-number \| interface-number.subnumber ] ]
Clear the Ethernet module statistics.	reset ethernet statistics [ slot slot-number ]
Clear the physical link state change statistics of interfaces.	reset link-state-change statistics interface [ interface-type [ interface-number ] ]
Clear the statistics of dropped packets on the specified interfaces.	reset packet-drop interface [ interface-type [ interface-number ] ]

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02-Layer 2-LAN Switching Configuration Guide

Configuring Ethernet interfaces

About Ethernet interface

About this task

Procedure

Restrictions and guidelines: Ethernet interface configuration

About this task

Restrictions and guidelines for 400-GE interface splitting and 200-GE breakout interface combining

Splitting a 400-GE interface into two 200-GE breakout interfaces

Combining two 200-GE breakout interfaces into a 400-GE interface

About this task

Restrictions and guidelines

Procedure

About this task

Restrictions and guidelines for Ethernet subinterface basic settings

Procedure

About this task

Restrictions and guidelines

Procedure

About this task

Procedure

About this task

Restrictions and guidelines

Procedure

About this task

Parameters

Restrictions and guidelines

Procedure

About this task

Restrictions and guidelines

Procedure

About this task

Restrictions and guidelines

Procedure

About this task

Restrictions and guidelines

Procedure

About this task

Restrictions and guidelines

Procedure

Setting the statistics polling interval

About this task

Setting the statistics polling interval in Ethernet interface view

About this task

Restrictions and guidelines

Procedure

About this task

Restrictions and guidelines

Procedure

About this task

Restrictions and guidelines

Enabling interface alarm functions

Configuring CRC error packet parameters

Configuring input error packet alarm parameters

Configuring output error packet alarm parameters

Configuring input bandwidth usage alarm parameters

Configuring received pause frame alarm parameters

Configuring sent pause frame alarm parameters

About this task

Restrictions and guidelines

Procedure

Configuring storm control on an Ethernet interface

About this task

Procedure

Enabling bridging on an Ethernet interface

About this task

Procedure

Configuring a Layer 3 Ethernet interface or subinterface

Setting the MTU for an Ethernet interface or subinterface

About this task

Restrictions and guidelines

Procedure

Setting the MAC address of an Ethernet interface or subinterface

About this task

Procedure

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