03-Layer 2—LAN Switching Configuration Guide

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01-Ethernet interface configuration
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Contents

Configuring Ethernet interfaces· 1

About Ethernet interface· 1

Configuring a management Ethernet interface· 1

Ethernet interface naming conventions· 1

Configuring common Ethernet interface settings· 2

Configuring the physical type for a combo interface (single combo interface) 2

Splitting a 40-GE interface and combining 10-GE breakout interfaces· 3

Splitting a 100-GE interface and combining 25-GE breakout interfaces· 3

Configuring basic settings of an Ethernet interface· 4

Configuring basic settings of an Ethernet subinterface· 5

Configuring the link mode of an Ethernet interface· 6

Configuring jumbo frame support 6

Configuring physical state change suppression on an Ethernet interface· 7

Configuring dampening on an Ethernet interface· 7

Configuring storm suppression· 9

Configuring generic flow control on an Ethernet interface· 10

Setting the statistics polling interval 10

Enabling loopback testing on an Ethernet interface· 11

Forcibly bringing up a fiber port 11

Restoring the default settings for an interface· 13

Configuring a Layer 2 Ethernet interface· 13

Configuring storm control on an Ethernet interface· 13

Testing the cable connection of an Ethernet interface· 14

Enabling bridging on an Ethernet interface· 15

Configuring Layer 3 forwarding on a Layer 2 Ethernet interface· 15

Configuring a Layer 3 Ethernet interface or subinterface· 16

Setting the MTU for an Ethernet interface or subinterface· 16

Display and maintenance commands for Ethernet interfaces· 16

 

 


Configuring Ethernet interfaces

About Ethernet interface

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 this task

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.

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

CAUTION:

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

 

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.

·     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 into 10-GE breakout interfaces, 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."

Configuring the physical type for a combo interface (single combo interface)

About this task

A combo interface is a logical interface that physically comprises one fiber combo port and one copper combo port. The two ports share one forwarding channel and one interface view. As a result, they cannot work simultaneously. When you activate one port, the other port is automatically disabled. If you execute the combo enable auto command on a combo interface, the interface automatically identifies the media inserted and activates the corresponding combo port. In the interface view, you can activate the fiber or copper combo port, and configure other port attributes such as the interface rate and duplex mode.

Prerequisites

Before you configure combo interfaces, complete the following tasks:

·     Determine the combo interfaces on your device. Identify the two physical interfaces that belong to each combo interface according to the marks on the device panel.

·     Use the display interface command to determine which port (fiber or copper) of each combo interface is active:

¡     If the copper port is active, the output includes "Media type is twisted pair."

¡     If the fiber port is active, the output does not include this information.

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Activate the copper combo port or fiber combo port.

combo enable { auto | copper | fiber }

The default is auto.

Splitting a 40-GE interface and combining 10-GE breakout interfaces

About this task

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 this feature to take effect. To view information about the breakout or combined interfaces, execute the display interface brief command. The 10-GE breakout interfaces cannot act as IRF physical interfaces.

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

1.     Enter system view.

system-view

2.     Enter 40-GE interface view.

interface fortygige 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 ten-gigabitethernet 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.

Splitting a 100-GE interface and combining 25-GE breakout interfaces

About this task

You can use a 100-GE interface as a single interface. To improve port density, reduce costs, and improve network flexibility, you can also split a 100-GE interface into four 25-GE breakout interfaces. The 25-GE breakout interfaces support the same configuration and attributes as common 25-GE interfaces, except that they are numbered differently.

For example, you can split 100-GE interface HundredGigE 1/0/1 into four 25-GE breakout interfaces Twenty-FiveGigE 1/0/1:1 through Twenty-FiveGigE 1/0/1:4.

If you need higher bandwidth on a single interface, you can combine the four 25-GE breakout interfaces into a 100-GE interface.

 

Restrictions and guidelines for 100-GE interface splitting and 25-GE breakout interface combining

·     A 100-GE interface split into four 25-GE breakout interfaces must use a dedicated 1-to-4 cable. After you combine the four 25-GE breakout interfaces, replace the dedicated 1-to-4 cable with a dedicated 1-to-1 cable or a 100-GE transceiver module. For more information about the cable or transceiver module, see the installation guides.

·     This feature is available only on devices that support 100-GE interfaces.

·     Device reboot is not required for this feature to take effect. To view information about the breakout or combined interfaces, execute the display interface brief command. The 25-GE breakout interfaces cannot act as IRF physical interfaces.

Splitting a 100-GE interface into four 25-GE breakout interfaces

1.     Enter system view.

system-view

2.     Enter 100-GE interface view.

interface hundredgige interface-number

3.     Split the 100-GE interface into four 25-GE breakout interfaces.

using twenty-fivegige

By default, a 100-GE interface is not split and operates as a single interface.

Combining four 25-GE breakout interfaces into a 100-GE interface

1.     Enter system view.

system-view

2.     Enter the view of any 25-GE breakout interface.

interface twenty-fivegige interface-number

3.     Combine the four 25-GE breakout interfaces into a 100-GE interface.

using hundredgige

By default, a 25-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 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 { 10 | 100 | 1000 | 2500 | 5000 | 10000 | 25000 | 40000 | 100000 | 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 with the VLAN tag numbered the same as the subinterface number.

Restrictions and guidelines for Ethernet subinterface basic settings

·     The shutdown, port up-mode, and loopback 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.     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 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.

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

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.

 

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 10000 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 and dampening 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

Restrictions and guidelines

·     The dampening and link-delay 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.

Configuring storm suppression

About this task

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.

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 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.

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

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 inter-device link. The Ethernet interface sends incoming packets back to the remote device. If the remote device fails to receive the packets, the inter-device link fails.

Restrictions and guidelines

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

·     You cannot perform a loopback test on the following Ethernet interfaces:

¡     Ethernet interfaces manually brought down (displayed as in ADM or Administratively DOWN state).

¡     Ethernet interfaces configured with the port up-mode command.

·     The speed, duplex, 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 }

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

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 by using the shutdown command.

·     A fiber port does not support this feature if the port joins an aggregation group.

·     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.

Restoring the default settings for an interface

Restrictions and guidelines

CAUTION

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 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.

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. For more information about storm suppression, see "Configuring storm suppression."

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.

Testing the cable connection of an Ethernet interface

IMPORTANT

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.

About this task

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.

Restrictions and guidelines

Fiber ports do not support this feature.

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 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 Layer 3 forwarding on a Layer 2 Ethernet interface

About this task

This feature enables a Layer 2 Ethernet interface to deliver a packet of which the destination MAC address is its own MAC address to the CPU for Layer 3 forwarding. If this feature is disabled, a Layer 2 Ethernet interface floods such a packet in the VLAN to which the packet belongs instead of delivering the packet to the CPU.

On a network where a firewall is attached to the device for transparent packet inspection, disable this feature on Layer 2 Ethernet interfaces on the device. In this way, the device will forward Layer 3 packets to the firewall for packet inspection and the firewall forwards only packets that pass packet inspection back to the device for further forwarding.

Procedure

1.     Enter system view.

system-view

2.     Enter Layer 2 Ethernet interface view.

interface interface-type interface-number

3.     Enable Layer 3 forwarding on the interface.

port ip-forwarding enable

By default, Layer 3 forwarding is enabled on an 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 MTU for the interface.

mtu size

The default setting is 1500 bytes.

Display and maintenance commands for Ethernet interfaces

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 storm control on the specified interfaces.

display storm-constrain [ broadcast | multicast | unicast ] [ interface interface-type interface-number ]

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 ] ]

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