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 installation guide.

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

Configuring a management Ethernet interface

About a management interface

A management interface uses an RJ-45 connector. You can connect the interface to a PC for software loading and system debugging, or connect it to a remote NMS for remote system management.

Each member device in an IRF system has a management Ethernet interface. For management link backup, perform the following tasks:

1. Connect your PC to the management Ethernet interface on the master device.

2. Connect the PC to a management Ethernet interface with the same interface number on a subordinate device.

The two management Ethernet interfaces operate as follows:

· When the IRF system has multiple management Ethernet interfaces, only the management Ethernet interface on the master device processes management traffic.

· When the management Ethernet interface on the master device fails, the management Ethernet interface on the subordinate device takes over to process management traffic.

· When the management Ethernet interface on the master device recovers, it takes over to process management traffic again.

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.

duplex { auto | full | half }

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

5. (Optional.) Set the speed.

speed { 10 | 100 | 1000 | auto }

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

6. (Optional.) Shut down the interface.

shutdown

By default, the management Ethernet interface is up.

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—IRF member ID. If the switch is not in an IRF fabric, A is 1 by default.

· B—Card slot number. 0 indicates the interface is a fixed interface of the switch. 1 indicates the interface is on expansion interface-card 1. 2 indicates the interface is on expansion interface-card 2.

· C—Port index.

A 10-GE breakout interface split from a 40-GE interface is named in the format of interface type A/B/C:D. A/B/C is the interface number of the 40-GE interface. D is the number of the 10-GE interface, which is in the range of 1 to 4. For information about splitting a 40-GE interface, see "Splitting a 40-GE interface and combining 10-GE breakout interfaces."

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 40-GE interface and combining 10-GE breakout interfaces

About 40-GE interface splitting and 10-GE breakout interface combining

You can use a 40-GE interface as a single interface. To improve port density, reduce costs, and improve network flexibility, you can also split a 40-GE interface into four 10-GE breakout interfaces. The 10-GE breakout interfaces support the same configuration and attributes as common 10-GE interfaces, except that they are numbered differently.

For example, you can split 40-GE interface FortyGigE 1/0/1 into four 10-GE breakout interfaces Ten-GigabitEthernet 1/0/1:1 through Ten-GigabitEthernet 1/0/1:4.

If you need higher bandwidth on a single interface, you can combine the four 10-GE breakout interfaces into a 40-GE interface.

Restrictions and guidelines for 40-GE interface splitting and 10-GE breakout interface combining

A 40-GE interface split into four 10-GE breakout interfaces must use a dedicated 1-to-4 cable. After you combine the four 10-GE breakout interfaces, replace the dedicated 1-to-4 cable with a dedicated 1-to-1 cable or a 40-GE transceiver module. For more information about the cable or transceiver module, see the installation guides.

Device reboot is not required for the interface type changes to take effect. To view information about the breakout or combined interfaces, execute the display interface brief command.

Splitting a 40-GE interface into four 10-GE breakout interfaces

1. Enter system view.

system-view

2. Enter 40-GE interface view.

interface interface-type interface-number

3. Split the 40-GE interface into four 10-GE breakout interfaces.

using tengige

By default, a 40-GE interface is not split and operates as a single interface.

Combining four 10-GE breakout interfaces into a 40-GE interface

1. Enter system view.

system-view

2. Enter the view of any 10-GE breakout interface.

interface interface-type interface-number

3. Combine the four 10-GE breakout interfaces into a 40-GE interface.

using fortygige

By default, a 10-GE breakout interface operates as a single interface.

Configuring basic settings of an Ethernet interface

About Ethernet interface basic settings

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 and port up-mode commands are mutually exclusive.

The shutdown command cannot be configured on an Ethernet interface in a loopback test.

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, Ten-GigabitEthernet1/0/1 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 { 1000 | 10000 | 40000 | 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

Restrictions and guidelines for Ethernet subinterface basic settings

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

· The shutdown command cannot be executed on an Ethernet interface in a loopback test.

· An Ethernet subinterface transmits packets carrying the VLAN tag numbered the same as the Ethernet subinterface. Do not use the VLAN as a common VLAN.

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, Ten-GigabitEthernet1/0/1.1 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 the link mode of an Ethernet interface

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

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

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.

Configuring jumbo frame support

About jumbo frame

Jumbo frames are frames larger than a fixed 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 9216 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 physical state change suppression

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.

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

On an interface, you can configure different suppression intervals for link-up and link-down events.

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

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

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

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 a port goes up or comes down, the interface immediately reports the change to the CPU.

Configuring dampening on an Ethernet interface

About dampening

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.

IRF system stability might be affected by IRF physical link flapping. For IRF system stability, this feature is enabled by default on IRF physical interfaces and the enabling status of this feature is not affected by the status of global link flapping protection. When the number of flaps detected on an IRF physical interface exceeds the threshold within the detection interval, the device outputs a log rather than shuts down the IRF physical interface.

The 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 ] *

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

Configuring storm suppression

About storm suppression

The storm suppression feature ensures that the size of a particular type of traffic (broadcast, multicast, or unknown unicast traffic) does not exceed the threshold on an interface. When the broadcast, multicast, or unknown unicast traffic on the interface exceeds this threshold, the system discards packets until the traffic drops below this threshold.

Both storm suppression and storm control can suppress storms on an interface. Storm suppression uses the chip to suppress traffic. Storm suppression has less impact on the device performance than storm control, which uses software to suppress traffic.

Restrictions and guidelines

· For the traffic suppression result to be determined, do not configure storm control together with storm suppression for the same type of traffic. For more information about storm control, see "Configuring storm control on an Ethernet interface."

· When you configure the suppression threshold in kbps, the actual suppression threshold might be different from the configured one as follows:

¡ If the configured value is smaller than 64, the value of 64 takes effect.

¡ If the configured value is greater than 64 but not an integer multiple of 64, the integer multiple of 64 that is greater than and closest to the configured value takes effect.

For the suppression threshold that takes effect, see the prompt on the device.

· Set the same type of thresholds for each interface.

Procedure

1. Enter system view.

system-view

2. Enter Ethernet interface view.

interface interface-type interface-number

3. Enable broadcast suppression and set the broadcast suppression threshold.

broadcast-suppression { ratio | pps max-pps | kbps max-kbps }

By default, broadcast suppression is disabled.

4. Enable multicast suppression and set the multicast suppression threshold.

multicast-suppression { ratio | pps max-pps | kbps max-kbps }

By default, multicast suppression is disabled.

5. Enable unknown unicast suppression and set the unknown unicast suppression threshold.

unicast-suppression { ratio | pps max-pps | kbps max-kbps }

By default, unknown unicast suppression is disabled.

Configuring generic flow control on an Ethernet interface

About generic flow control

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

The flow-control, flow-control receive enable, and priority-flow-control no-drop dot1p commands are mutually exclusive.

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.

Configuring PFC on an Ethernet interface

About PFC

When congestion occurs in the network, the local device notifies the peer to stop sending packets carrying the specified 802.1p priority if all of the following conditions exist:

· Both the local end and the remote end have priority-based flow control (PFC) enabled.

· Both the local end and the remote end have the priority-flow-control no-drop dot1p command configured.

· The specified 802.1p priority is in the 802.1p priority list specified by the dot1p-list argument.

· The local end receives a packet carrying the specified 802.1p priority.

Restrictions and guidelines

· For IRF and other protocols to operate correctly, as a best practice, do not enable PFC for 802.1p priorities 0, 6, and 7.

· To perform PFC in an overlay network, execute the qos trust tunnel-dot1p command. For information about the overlay network, see VXLAN Configuration Guide. For information about the qos trust tunnel-dot1p command, see ACL and QoS Command Reference.

· To avoid packet loss, apply the same PFC configuration to all interfaces that the packets pass through.

· If you do not enable PFC on an interface, the interface can receive but cannot process PFC pause frames. To make PFC take effect, you must enable PFC on both ends.

· If you configure the flow control or flow-control receive enable command on a PFC-enabled interface, the following rules apply:

¡ The PFC configuration takes effect.

¡ The configuration of the flow control or flow-control receive enable command is ignored.

¡ The flow control or flow-control receive enable command takes effect on the interface only when PFC is disabled on it.

· The priority-flow-control no-drop, flow-control, and flow-control receive enable commands are mutually exclusive.

Procedure

1. Enter system view.

system-view

2. Enter Ethernet interface view.

interface interface-type interface-number

3. Enable PFC in auto mode or forcibly on the Ethernet interface.

priority-flow-control { auto | enable }

By default, PFC is disabled.

4. Enable PFC for 802.1p priorities.

priority-flow-control no-drop dot1p dot1p-list

By default, PFC is disabled for all 802.1p priorities.

Enabling energy saving features on an Ethernet interface

About energy saving features on an Ethernet interface

This feature contains auto power-down and Energy Efficient Ethernet (EEE) on an Ethernet interface.

When an Ethernet interface with auto power-down enabled has been down for a certain period of time, both of the following events occur:

· The device automatically stops supplying power to the Ethernet interface.

· The Ethernet interface enters the power save mode.

The time period depends on the chip specifications and is not configurable.

When the Ethernet interface comes up, both of the following events occur:

· The device automatically restores power supply to the Ethernet interface.

· The Ethernet interface restores to its normal state.

With Energy Efficient Ethernet (EEE) enabled, a link-up interface enters low power state if it has not received any packet for a period of time. The time period depends on the chip specifications and is not configurable. When a packet arrives later, the device automatically restores power supply to the interface and the interface restores to the normal state.

Restrictions and guidelines

Fiber ports do not support this feature.

Configuring auto power-down on an Ethernet interface:

1. Enter system view.

system-view

2. Enter Ethernet interface view.

interface interface-type interface-number

3. Enable auto power-down on the Ethernet interface.

port auto-power-down

By default, auto power-down is disabled on an Ethernet interface.

Configuring EEE on an Ethernet interface

1. Enter system view.

system-view

2. Enter Ethernet interface view.

interface interface-type interface-number

3. Enable EEE on the Ethernet interface.

eee enable

By default, EEE is disabled on an Ethernet interface.

Setting the statistics polling interval

About statistics polling interval

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 loopback testing

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

· An Ethernet interface in a loopback test cannot correctly forward data packets.

· You cannot perform a loopback test on Ethernet interfaces manually brought down (displayed as in ADM or Administratively DOWN state).

· The speed, duplex, mdix-mode, and shutdown commands cannot be configured on an Ethernet interface in a loopback test.

· 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. Enable loopback testing.

loopback { external | internal }

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

Setting the MDIX mode of an Ethernet interface

IMPORTANT:

Fiber ports do not support the MDIX mode setting.

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About MDIX mode

A physical Ethernet interface has eight pins, each of which plays a dedicated role. For example, pins 1 and 2 transmit signals, and pins 3 and 6 receive signals. 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-Crossover (MDIX) modes:

· MDIX mode—Pins 1 and 2 are receive pins and pins 3 and 6 are transmit pins.

· MDI mode—Pins 1 and 2 are transmit pins and pins 3 and 6 are receive pins.

· AutoMDIX mode—The interface negotiates pin roles with its peer.

NOTE:

This feature does not take effect on pins 4, 5, 7, and 8 of physical Ethernet interfaces.

· Pins 4, 5, 7, and 8 of interfaces operating at 10 Mbps or 100 Mbps do not receive or transmit signals.

· Pins 4, 5, 7, and 8 of interfaces operating at 1000 Mbps or higher rates receive and transmit signals.

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Restrictions and guidelines

To enable a copper Ethernet interface to communicate with its peer, set the MDIX mode of the interface by following these guidelines:

· Typically, set the MDIX mode of the interface to AutoMDIX. Set the MDIX mode of the interface to MDI or MDIX only when the device cannot determine the cable type.

· When a straight-through cable is used, configure the interface to operate in an MDIX mode different than its peer.

· When a crossover cable is used, perform one of the following tasks:

¡ Configure the interface to operate in the same MDIX mode as its peer.

¡ Configure either end to operate in AutoMDIX mode.

Procedure

1. Enter system view.

system-view

2. Enter Ethernet interface view.

interface interface-type interface-number

3. Set the MDIX mode of the Ethernet interface.

mdix-mode { automdix | mdi | mdix }

By default, a copper Ethernet interface operates in auto mode to negotiate pin roles with its peer.

Configuring storm control on an Ethernet interface

About storm control

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.

Restrictions and guidelines

For the traffic suppression result to be determined, do not configure storm control together with storm suppression for the same type of traffic.

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.

Forcibly bringing up a fiber port

About forcibly bringing up a fiber port

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

· Copper ports do not support this feature.

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

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

· A fiber port does not support this feature if the port joins a Layer 2 aggregation group.

· The following operations on a fiber port will cause link-down and link-up events before the port finally stays up:

¡ Configure both the port up-mode command and the speed or duplex command.

¡ Install or remove fibers or transceiver modules after you forcibly bring up the fiber 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.

Testing the cable connection of an Ethernet interface

IMPORTANT:

If the link of an Ethernet interface is up, testing its cable connection will cause the link to go down and then come up.

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NOTE:

Fiber ports do not support this feature.

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About testing the cable connection of an Ethernet interface

This feature tests the cable connection of an Ethernet interface and displays cable test result within 5 seconds. The test result includes the cable's status and some physical parameters. If any fault is detected, the test result shows the length from the local port to the faulty point.

Procedure

1. Enter system view.

system-view

2. Enter Ethernet interface view.

interface interface-type interface-number

3. Perform a test for the cable connected to the Ethernet interface.

virtual-cable-test

Enabling bridging on an Ethernet interface

About enabling bridging on an Ethernet interface

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

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.

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 ] ]
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 ] ]
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 information about link flapping protection on interfaces.	display link-flap protection [ interface interface-type [ interface-number ] ]
Display information about dropped packets on the specified interfaces.	display packet-drop { interface [ interface-type [ interface-number ] ] \| summary }
Display the PFC information for an interface.	display priority-flow-control interface [ interface-type [ interface-number ] ]
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 statistics of dropped packets on the specified interfaces.	reset packet-drop interface [ interface-type [ interface-number ] ]

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03-Layer 2—LAN Switching Configuration Guide

Configuring Ethernet interfaces

About Ethernet interface

About a management interface

Procedure

Configuring common Ethernet interface settings

About 40-GE interface splitting and 10-GE breakout interface combining

Restrictions and guidelines for 40-GE interface splitting and 10-GE breakout interface combining

Splitting a 40-GE interface into four 10-GE breakout interfaces

Combining four 10-GE breakout interfaces into a 40-GE interface

About Ethernet interface basic settings

Restrictions and guidelines

Procedure

Restrictions and guidelines for Ethernet subinterface basic settings

Procedure

About the link mode of an Ethernet interface

Restrictions and guidelines

Procedure

About jumbo frame

Procedure

About physical state change suppression

Restrictions and guidelines

Procedure

About dampening

Parameters

Restrictions and guidelines

Procedure

About this task

Restrictions and guidelines

Procedure

About storm suppression

Restrictions and guidelines

Procedure

About generic flow control

Restrictions and guidelines

Procedure

About PFC

Procedure

Enabling energy saving features on an Ethernet interface

About energy saving features on an Ethernet interface

Restrictions and guidelines

Configuring auto power-down on an Ethernet interface:

Configuring EEE on an Ethernet interface

About statistics polling interval

Setting the statistics polling interval in Ethernet interface view

About loopback testing

Restrictions and guidelines

Procedure

Setting the MDIX mode of an Ethernet interface

About MDIX mode

Restrictions and guidelines

Procedure

About storm control

Restrictions and guidelines

Procedure

Forcibly bringing up a fiber port

About forcibly bringing up a fiber port

Restrictions and guidelines

Procedure

About testing the cable connection of an Ethernet interface

Procedure

Enabling bridging on an Ethernet interface

About enabling bridging on an Ethernet interface

Procedure

Configuring a Layer 3 Ethernet interface or subinterface

Setting the MTU for an Ethernet interface or subinterface

Restrictions and guidelines

Procedure

Display and maintenance commands

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