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.

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.

Configuring a management Ethernet 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.

To configure a management Ethernet interface:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter management Ethernet interface view.	interface M-GigabitEthernet interface-number	N/A
3. (Optional.) Set the interface description.	description text	The default setting is M-GigabitEthernet0/0/0 Interface.
4. (Optional.) Shut down the interface.	shutdown	By default, the management Ethernet interface is up.

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 or subinterfaces, 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 a combo interface (single combo interface)

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.

Configuration 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.

Changing the active port of a combo interface

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Activate the copper combo port or fiber combo port.	combo enable { auto \| copper \| fiber }	By default, the combo interface automatically identifies the media inserted and activates the corresponding combo port.

Configuring basic settings of an Ethernet interface or subinterface

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.

· Half-duplex mode—The interface can only send or receive packets at a given time.

· 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.

Configuring an Ethernet interface

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Set the description for the Ethernet interface.	description text	The default setting is interface-name Interface. For example, GigabitEthernet1/0/1 Interface.
4. Set the duplex mode for the Ethernet interface.	duplex { auto \| full \| half }	By default, the duplex mode is auto for Ethernet interfaces. Copper ports operating at 1000 Mbps or 10 Gbps and fiber ports do not support the half keyword.
5. Set the speed for the Ethernet interface.	speed { 10 \| 100 \| 1000 \| 10000 \| 20000 \| auto }	The default setting is auto for Ethernet interfaces. Support for the keywords depends on the interface type. For more information, use the speed ? command in interface view.
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. Restore the default settings for the Ethernet interface.	default	N/A
8. Bring up the Ethernet interface.	undo shutdown	By default, Ethernet interfaces are in up state. The shutdown and port up-mode commands are mutually exclusive. The shutdown command cannot be configured on an interface in a loopback test.

Configuring an Ethernet subinterface

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Create an Ethernet subinterface.	interface interface-type interface-number.subnumber	N/A
3. Set the description for the Ethernet subinterface.	description text	The default setting is interface-name Interface. For example, GigabitEthernet1/0/1.1 Interface.
4. Restore the default settings for the Ethernet subinterface.	default	N/A
5. 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.
6. Bring up the Ethernet subinterface.	undo shutdown	By default, Ethernet subinterfaces are in up state. The shutdown and port up-mode commands are mutually exclusive. The shutdown command cannot be configured on an interface in a loopback test.

Configuring the link mode of an Ethernet interface

CAUTION:

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

The interfaces on this Switch Series can operate either as Layer 2 or Layer 3 Ethernet interfaces.

You can set the link mode to bridge or route.

To configure the link mode of an Ethernet interface:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Configure the link mode of the Ethernet interface.	port link-mode { bridge \| route }	By default, Ethernet interfaces operate in bridge mode.

Configuring jumbo frame support

An Ethernet interface might receive frames larger than the standard Ethernet frame size during high-throughput data exchanges, such as file transfers. These frames are called jumbo frames.

The Ethernet interface processes jumbo frames in the following ways:

· When the Ethernet interface is configured to deny jumbo frames, 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.

To configure jumbo frame support in interface view:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Configure jumbo frame support.	jumboframe enable [ size ]	By default, the switch allows jumbo frames within 12288 bytes to pass through all Ethernet interfaces.

Configuring physical state change suppression on an Ethernet interface

IMPORTANT:

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

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.

When you configure this feature, follow these guidelines:

· To suppress only link-down events, configure the link-delay [ msec ] delay-time command.

· To suppress only link-up events, configure the link-delay [ msec ] delay-time mode up command.

· To suppress both link-down and link-up events, configure the link-delay [ msec ] delay-time mode updown command.

To configure physical state change suppression on an Ethernet interface:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Configure physical state change suppression.	link-delay [ msec ] delay-time [ mode { up \| updown } ]	By default, the link-down or link-up event is immediately reported to the CPU. If you configure this command multiple times on an Ethernet interface, the most recent configuration takes effect.

Configuring dampening on an Ethernet interface

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.

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

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

Configuration restrictions and guidelines

When you configure dampening on an Ethernet interface, follow these restrictions and guidelines:

· The dampening command and the link-delay command cannot be configured together 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.

Configuration procedure

To configure dampening on an Ethernet interface:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Enable dampening on the interface.	dampening [ half-life reuse suppress max-suppress-time ]	By default, interface dampening is disabled on Ethernet interfaces.

Enabling loopback testing on an Ethernet interface

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.

Configuration restrictions and guidelines

· On an administratively shut down Ethernet interface (displayed as in ADM or Administratively DOWN state), you cannot perform an internal or external loopback test.

· The speed, duplex, mdix-mode, and shutdown commands are unavailable during a loopback test.

· A loopback test cannot be performed on an interface configured with the port up-mode command.

· During a loopback test, the Ethernet interface operates in full duplex mode. When a loopback test is complete, the port returns to its duplex setting.

Configuration procedure

To enable loopback testing on an Ethernet interface:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Enable loopback testing.	loopback { external \| internal }	By default, no loopback test is performed.

Configuring generic flow control on an Ethernet interface

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.

To enable generic flow control on an Ethernet interface:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Enable 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

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 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.

The state of the PFC feature is determined by the PFC configuration on the local end and on the peer end. In Table 1:

· The first row lists the PFC configuration on the local interface.

· The first column lists the PFC configuration on the peer.

· The Enabled and Disabled fields in other cells are possible negotiation results.

Make sure all interfaces that a data flow passes through have the same PFC configuration.

Table 1 PFC configurations and negotiation results

Local (right) Peer (below)	enable	auto	Default
enable	Enabled	Enabled.	Disabled
auto	Enabled	· Enabled if negotiation succeeds. · Disabled if negotiation fails.	Disabled
Default	Disabled	Disabled.	Disabled

Configuration restrictions and guidelines

When you configure PFC, follow these 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 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.

Configuration procedure

To configure PFC on an Ethernet interface:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Enable 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

IMPORTANT:

Fiber ports do not support these features.

Enabling auto power-down 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.

To enable auto power-down on an Ethernet interface:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Enable auto power-down on the Ethernet interface.	port auto-power-down	By default, auto power-down is disabled on an Ethernet interface.

Enabling EEE on an Ethernet interface

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.

To enable EEE on an Ethernet interface:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Enable EEE on the Ethernet interface.	eee enable	By default, EEE is disabled on an Ethernet interface.

Setting the statistics polling interval

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Set the statistics polling interval for the Ethernet interface.	flow-interval interval	By default, the statistics polling interval is 300 seconds.

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

Enabling automatic negotiation for speed downgrading

Perform this task to enable interfaces at two ends of a link to automatically negotiate about downgrading their speed when the following conditions exist:

· The interfaces automatically negotiate a speed of 1000 Mbps.

· The interfaces cannot operate at 1000 Mbps because of link restrictions.

To enable automatic negotiation for speed downgrading:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Enable automatic negotiation for speed downgrading.	speed auto downgrade	By default, automatic negotiation for speed downgrading is enabled.

Configuring a Layer 2 Ethernet interface

Configuring 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.

Configuration restrictions and guidelines

When you configure storm suppression, follow these 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."

· If two or more types of the broadcast, multicast, and unknown unicast suppression thresholds are set on an interface, make sure they are set in the same unit.

· 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.

Configuration procedure

To set storm suppression thresholds on an Ethernet interface:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Enable 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 } [ unknown ]	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 storm control on an Ethernet interface

About storm control

Storm control compares broadcast, known unicast, 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.

Configuration 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 suppression, see "Configuring storm suppression."

Configuration procedure

To configure storm control on an Ethernet interface:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
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	N/A
4. (Optional.) Enable storm control, and set the lower and upper thresholds for broadcast, multicast, or unknown unicast traffic.	storm-constrain { broadcast \| known-unicast \| multicast \| unicast } { pps \| kbps \| ratio } max-pps-values min-pps-values	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. (Optional.) 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.
7. (Optional.) 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.

‌

Forcibly bringing up a fiber port

IMPORTANT:

Copper ports do not support this feature.

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

Configuration restrictions and guidelines

When you forcibly bring up a fiber port, follow these restrictions and guidelines:

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

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

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

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

· A GE fiber port forcibly brought up cannot correctly forward traffic if it is installed with a fiber-to-copper converter, 100/1000-Mbps transceiver module, or 100-Mbps transceiver module. To solve the problem, use the undo port up-mode command on the fiber port.

Configuration procedure

To forcibly bring up a fiber port:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
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.

Setting the MDIX mode of an Ethernet interface

IMPORTANT:

Fiber ports do not support the MDIX mode setting.

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.

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.

To set the MDIX mode of an Ethernet interface:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Set the 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. 10-GE interfaces support only the automdix mode.

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.

NOTE:

Fiber ports do not support this feature.

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.

To test the cable connection of an Ethernet interface:

Step	Command
1. Enter system view.	system-view
2. Enter Ethernet interface view.	interface interface-type interface-number
3. Perform a test for the cable connected to the Ethernet interface.	virtual-cable-test

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.

To enable bridging on an Ethernet interface:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface view.	interface interface-type interface-number	N/A
3. Enable 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

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.

To set the MTU for an Ethernet interface or subinterface:

Step	Command	Remarks
1. Enter system view.	system-view	N/A
2. Enter Ethernet interface or subinterface view.	interface interface-type { interface-number \| interface-number.subnumber }	N/A
3. Set the MTU of the Ethernet interface or subinterface.	mtu size	The default setting is 1500 bytes.

Displaying and maintaining an Ethernet interface or subinterface

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 operational and status information of the specified interfaces.	display interface [ interface-type [ interface-number \| interface-number.subnumber ] ] [ brief [ description \| down ] ]
Display information about dropped packets on the specified interfaces.	display packet-drop { interface [ interface-type [ interface-number \| interface-number.subnumber ] ] \| 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 \| known-unicast \| multicast \| unicast ] [ interface interface-type interface-number ]
Display the Ethernet module statistics.	display ethernet statistics slot slot-number
Clear interface or subinterface statistics.	reset counters interface [ interface-type [ interface-number \| interface-number.subnumber ] ]
Clear the statistics of dropped packets on the specified interfaces.	reset packet-drop interface [ interface-type [ interface-number \| interface-number.subnumber ] ]
Clear the Ethernet module statistics.	reset ethernet statistics [ slot slot-number ]

03-Layer 2—LAN Switching Configuration Guide

Configuring Ethernet interfaces

Configuring common Ethernet interface settings

Configuring a combo interface (single combo interface)

Configuration prerequisites

Changing the active port of a combo interface

Configuring an Ethernet interface

Configuring an Ethernet subinterface

Parameters

Configuration restrictions and guidelines

Configuration procedure

Configuration restrictions and guidelines

Configuration procedure

Configuration restrictions and guidelines

Configuration procedure

Enabling auto power-down on an Ethernet interface

Enabling EEE on an Ethernet interface

Configuring storm suppression

Configuration restrictions and guidelines

Configuration procedure

About storm control

Configuration restrictions and guidelines

Configuration procedure

Forcibly bringing up a fiber port

Configuration restrictions and guidelines

Configuration procedure

Enabling bridging on an Ethernet interface

Configuring a Layer 3 Ethernet interface or subinterface

Setting the MTU for an Ethernet interface or subinterface

Displaying and maintaining an Ethernet interface or subinterface

Intelligent Terminal Products

Product Support Services

Technical Service Solutions

Resource Center

Policy

Online Help

Become a Partner

Partner Policy & Program

Global Learning

Partner Sales Resources

Service Business

News & Events

Contact Us