Configuring Ethernet interfaces· 1

Ethernet interface naming conventions 1

Performing general configurations 1

Configuring basic settings of an Ethernet interface· 1

Shutting down an Ethernet interface· 2

Configuring generic flow control on an Ethernet interface· 2

Configuring physical state change suppression on an Ethernet interface· 3

Configuring loopback testing on an Ethernet interface· 4

Configuring jumbo frame support 5

Enabling auto power-down· 6

Setting a statistics polling interval 6

Configuring a Layer 2 Ethernet interface· 6

Layer 2 Ethernet interface configuration task list 6

Setting speed options for autonegotiation on an Ethernet interface· 7

Configuring storm suppression· 8

Enabling loopback detection on an Ethernet interface· 9

Setting the MDI mode of an Ethernet interface· 11

Enabling bridging on an Ethernet interface· 12

Testing the cable connection of an Ethernet interface· 13

Configuring storm control on an Ethernet interface· 13

Displaying and maintaining an Ethernet interface· 14

 

Ethernet interface naming conventions

The Ethernet interfaces on the WX5540E switching engines are named in the format of interface-type A/B/C, where the following definitions apply:

·          A—1.

·          B—Represents a slot number on the switch, and its value is 0.

·          C—Represents the number of an interface.

Performing general configurations

Configuring basic settings of an Ethernet interface

You can set an Ethernet interface to operate in one of these duplex modes:

·          Full-duplex mode (full)—Interfaces that operate in this mode can send and receive packets simultaneously.

·          Half-duplex mode (half)—Interfaces that operate in this mode cannot send and receive packets simultaneously.

·          Autonegotiation mode (auto)—Interfaces that operate in this mode negotiate a duplex mode with their peers.

You can set the speed of an Ethernet interface or enable it to automatically negotiate a speed with its peer. For a GE Layer 2 interface, you can also set speed options for autonegotiation. The two ends can select a speed only from the available options. For more information, see "Setting speed options for autonegotiation on an Ethernet interface."

Make sure that the fiber port speed matches the speed requirement of the inserted transceiver module. For example, after you insert a 1000-Mbps transceiver module into a fiber port, configure the port speed with the speed 1000 or speed auto command.

To configure 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 interface description.	description text	Optional. By default, the description of an interface is in the format of interface-name Interface. For example, GigabitEthernet1/0/1 Interface.
4.       Set the duplex mode of the interface.	duplex { auto | full | half }	Optional. By default, the duplex mode is auto.
5.       Set the port speed.	speed { 10 | 100 | 1000 | 10000 | auto }	Optional. By default, an Ethernet interface automatically negotiates a speed with the peer. GE fiber ports do not support the 10 or 10000 keyword. 10-GE fiber ports do not support the 10, 100, or 1000 keyword. GE copper ports do not support the 10000 keyword.
6.       Restore the default settings for the interface.	default	Optional.

 

Shutting down an Ethernet interface

CAUTION: Use this command with caution. After you manually shut down an Ethernet interface, the Ethernet interface cannot forward packets even if it is physically connected.

 

You might need to shut down and then bring up an Ethernet interface to activate some configuration changes, for example, the speed or duplex mode changes.

To shut down an Ethernet interface:

 

Step	Command	Remarks
1.       Enter system view.	system-view	N/A
2.       Enter Ethernet interface view or port group view.	·      Enter Ethernet interface view: interface interface-type interface-number ·      Enter port group view: port-group manual port-group-name	To shut down an Ethernet interface , enter Ethernet interface view. To shut down all Ethernet interfaces in a port group, enter port group view.
3.       Shut down the Ethernet interface.	shutdown	By default, Ethernet interfaces are up.

 

Configuring generic flow control on an Ethernet interface

You can avoid packet drops on a link by enabling generic flow control at both ends of the link. The flow control function enables the receiving end to require the sending end to suspend sending packets when congestion occurs.

An interface implements generic flow control by sending and receiving common pause frames. The following generic flow control modes are available:

·          TxRx mode—Enables an interface to both send and receive common pause frames.

·          Rx mode—Enables an interface to receive but not send common pause frames.

In Figure 1, when both Port A and Port B forward packets at 1000 Mbps, Port C is easily congested. To avoid packet loss, enable generic flow control on Port A and Port B.

Figure 1 Generic flow control application

 

Configure Port B to operate in TxRx mode and Port A to operate in Rx mode:

·          When congestion occurs on Port C, Switch B buffers frames. When the amount of buffered frames exceeds a certain value, Switch B sends a common pause frame out of Port B to ask Port A to suspend sending packets. This pause frame also tells Port A for how long it is expected to pause.

·          Upon receiving the common pause frame from Port B, Port A temporarily stops sending packets to Port B.

·          If congestion persists, Port B keeps sending common pause frames to Port A until the congestion condition is removed.

To configure 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 flow control.	·      Enable TxRx mode flow control: flow-control ·      Enable Rx mode flow control: flow-control receive enable	Use either command. By default, generic flow control is disabled on an Ethernet interface.

 

Configuring physical state change suppression on an Ethernet interface

An Ethernet interface has two physical link states: up and down. Each time the physical link of an interface goes up or comes down, the physical layer reports the change to the upper layers, and the upper layers handle the change, resulting in increased overhead.

To prevent physical link flapping from affecting system performance, configure link change suppression to delay the reporting of physical link state changes. When the delay expires, the interface reports any detected change.

Link change suppression does not suppress administrative up or down events. When you shut down or bring up an interface by using the shutdown or undo shutdown command, the interface immediately reports the event to the upper layers.

Link-down event suppression enables an interface to suppress link-down events and start a delay timer each time the physical link goes down. During this delay, the interface does not report the link-down event, and the display interface brief or display interface command displays the interface state as UP. If the physical link is still down when the timer expires, the interface reports the link-down event to the upper layers.

Link-up event suppression enables an interface to suppress link-up events and start a delay timer each time the physical link goes up. During this delay, the interface does not report the link-up event, and the display interface brief or display interface command displays the interface state as DOWN. If the physical link is still up when the timer expires, the interface reports the link-up event to the upper layers.

Configuring link-down event 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.       Set a link-down event suppression interval.	link-delay delay-time	Link-down event suppression is disabled by default. The link-delay command and the link-delay mode up command supersede each other. The last command you configure takes effect.

 

Configuring link-up event 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.       Set a link-up event suppression interval.	link-delay delay-time mode up	Link-up event suppression is disabled by default. The link-delay mode up command and the link-delay command supersede each other. The last command that you configure takes effect.

 

Configuring loopback testing on an Ethernet interface

If an Ethernet interface does not work normally, you can enable loopback testing on it to identify the problem. An Ethernet interface in a loopback test does not forward data traffic.

Loopback testing has the following types:

·          Internal loopback testing—Tests all on-chip functions related to Ethernet interfaces.

·          External loopback testing—Tests hardware of Ethernet interfaces. To perform external loopback testing on an Ethernet interface, connect a loopback plug to the Ethernet interface. The device sends test packets out of the interface, which are expected to loop over the plug and back to the interface. If the interface fails to receive any test packets, the hardware of the interface is faulty.

Configuration restrictions and guidelines

·          On an interface administratively shut down, you cannot perform internal or external loopback testing.

·          The speed, duplex, mdi, and shutdown commands are not available during loopback testing.

·          During loopback testing, the Ethernet interface operates in full duplex mode. When you disable loopback testing, the port returns to its duplex setting.

·          Loopback testing is a one-time operation, and is not recorded in the configuration file.

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, loopback testing is disabled.

 

Configuring jumbo frame support

An Ethernet interface might receive some frames larger than the standard Ethernet frame size (called "jumbo frames") during high-throughput data exchanges such as file transfers. Usually, an Ethernet interface discards jumbo frames. With jumbo frame support enabled, the interface can process frames larger than the standard Ethernet frame size yet within the specified range.

In Ethernet interface view or port group view, you can set the length of jumbo frames that are allowed to pass through Ethernet interfaces, as follows:

·          If you execute the command in Ethernet interface view, the configuration takes effect only on the interface.

·          If you execute the command in port group view, the configuration takes effect on all ports in the port group.

To configure jumbo frame support in interface view or port group view:

 

Step	Command	Remarks
1.       Enter system view.	system-view	N/A
2.       Enter interface view or port group view.	·      Enter Ethernet interface view: interface interface-type interface-number ·      Enter port group view: port-group manual port-group-name	Settings in interface view take effect on the interface. Settings in port group view take effect on all ports in the port group.
3.       Configure jumbo frame support.	jumboframe enable [ value ]	By default, the switch allows jumbo frames within 10000 bytes to pass through all Ethernet interfaces. When you configure the value argument multiple times, the most recent configuration takes effect.

 

Enabling auto power-down

With the auto power-down function, the system automatically stops supplying power to an interface if the interface is in the down state for a certain period of time (which depends on the chip specifications and is not configurable). The interface enters the power save mode. When the interface goes up, the system supplies power to the interface and the interface enters 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 interface view or port group view.	·      Enter Ethernet interface view: interface interface-type interface-number ·      Enter port group view: port-group manual port-group-name	Settings in interface view take effect on the interface. Settings in port group view take effect on all ports in the port group.
3.       Enable auto power-down.	port auto-power-down	By default, auto power-down is disabled.

 

NOTE: When you connect an interface enabled with auto power-down to a device, if the link cannot go up properly, disable auto power-down on the interface and try again.

 

Setting a statistics polling interval

You can configure an interface statistics polling interval. To display the interface statistics collected in the last polling interval, use the display interface or display counters rate command. To clear the interface statistics, use the reset counters interface command.

To set the statistics polling interval:

 

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

 

Configuring a Layer 2 Ethernet interface

Layer 2 Ethernet interface configuration task list

Task	Remarks
Setting speed options for autonegotiation on an Ethernet interface	Optional. Applicable to Layer 2 Ethernet interfaces.
Configuring storm suppression	Optional. Applicable to Layer 2 Ethernet interfaces.
Enabling loopback detection on an Ethernet interface	Optional. Applicable to Layer 2 Ethernet interfaces.
Setting the MDI mode of an Ethernet interface	Optional. Applicable to Layer 2 Ethernet interfaces.
Enabling bridging on an Ethernet interface	Optional. Applicable to Layer 2 Ethernet interfaces.
Testing the cable connection of an Ethernet interface	Optional. Applicable to Layer 2 Ethernet interfaces.
Configuring storm control on an Ethernet interface	Optional. Applicable to Layer 2 Ethernet interfaces.

 

Setting speed options for autonegotiation on an Ethernet interface

Speed autonegotiation enables an Ethernet interface to negotiate with its peer for the highest speed that both ends support by default. You can narrow down the speed option list for negotiation.

Figure 2 Speed autonegotiation application scenario

 

As shown in Figure 2, all ports on Switch A are operating in speed autonegotiation mode, with the highest speed of 1000 Mbps. If the transmission rate of each server in the server cluster is 1000 Mbps, their total transmission rate exceeds the capability of port GigabitEthernet 1/0/4, the port providing access to the Internet for the servers.

To avoid congestion on GigabitEthernet 1/0/4, set 100 Mbps as the only option available for speed negotiation on port GigabitEthernet 1/0/1, GigabitEthernet 1/0/2, and GigabitEthernet 1/0/3. As a result, the transmission rate on each port connected to a server is limited to 100 Mbps.

To set speed options for autonegotiation on an Ethernet interface:

 

Step	Command
1.       Enter system view.	system-view
2.       Enter Ethernet interface view.	interface interface-type interface-number
3.       Set speed options for autonegotiation.	speed auto { 10 | 100 | 1000 } *

 

This function is available only for GE Layer 2 interfaces that support speed autonegotiation.

The speed and speed auto commands supersede each other. The last command that you configure takes effect.

Configuring storm suppression

In interface or port group view, you set the maximum size of broadcast, multicast or unknown unicast traffic allowed to be received on an interface or each interface in a port group. When the broadcast, multicast, or unknown unicast traffic received on the interface exceeds this threshold, the system discards packets until the traffic drops below this threshold.

Configuration restrictions and guidelines

·          The storm suppression thresholds configured for an Ethernet interface may become invalid if you enable the storm control function for the interface. For information about the storm control function, see "Configuring storm control on an Ethernet interface."

·          To configure two or all of broadcast, multicast, and unknown unicast suppression thresholds on the same port, do not use pps together with kbps or ratio.

·          If you set a traffic suppression threshold for an Ethernet interface that belongs to a port group in both Ethernet interface view and port group view, the most recent configuration takes effect.

Configuration procedure

To set storm suppression thresholds on one or multiple Ethernet interfaces:

 

Step	Command	Remarks
1.       Enter system view.	system-view	N/A
2.       Enter Ethernet interface view or port group view.	·      Enter Ethernet interface view: interface interface-type interface-number ·      Enter port group view: port-group manual port-group-name	To configure storm suppression on an Ethernet interface, enter Ethernet interface view. To configure storm suppression on a group of Ethernet interfaces, enter port group view.
3.       Set the broadcast suppression threshold ratio.	broadcast-suppression { ratio | pps max-pps | kbps max-kbps }	Optional. By default, broadcast traffic is allowed to pass through an interface.
4.       Set the multicast suppression threshold ratio.	multicast-suppression { ratio | pps max-pps | kbps max-kbps }	Optional. By default, multicast traffic is allowed to pass through an interface.
5.       Set the unknown unicast suppression threshold ratio.	unicast-suppression { ratio | pps max-pps | kbps max-kbps }	Optional. By default, unknown unicast traffic is allowed to pass through an interface.

 

Enabling loopback detection on an Ethernet interface

If a device receives a packet that it sent, a loop has occurred to the device. Loops might cause broadcast storms, which degrade network performance. You can use this feature to detect whether a loop has occurred.

Depending on whether the receiving interface is the same as the sending interface, loops fall into the following types:

·          Single-port loopback—Single-port loopback occurs when an interface receives a packet that it sent and the receiving interface is the same as the sending interface, as shown in Figure 3.

·          Multi-port loopback—Multi-port loopback occurs when a device receives a packet that it sent but the receiving interface might not be the sending interface, as shown in Figure 4.

Figure 3 Single-port loopback

 

Figure 4 Multi-port loopback

 

You can enable loopback detection to detect loops on an interface and, if the interface supports the loopback-detection action command, configure the protective action to take on the receiving interface when a loop is detected, for example, to shut down the interface. Depending on whether a protective action is configured, the device takes the actions in Table 1 to alleviate the impact of the loop condition.

Table 1 Actions to take upon detection of a loop condition

Port type	Actions
	No protective action is configured	A protective action is configured
Access port	·      Place the receiving interface in controlled mode. The interface discards all incoming packets, but still forwards outgoing packets. ·      Generate traps and log messages. ·      Delete all MAC address entries of the interface.	·      Perform the configured protective action. ·      Generate traps and log messages. ·      Delete all MAC address entries of the interface.
Hybrid or trunk port	·      Generate traps and log messages. ·      If loopback detection control is enabled, place the receiving interface in controlled mode. The interface discards all incoming packets, but still forwards outgoing packets. ·      Delete all MAC address entries of the interface.	·      Generate traps and log messages. ·      If loopback detection control is enabled, take the configured protective action on the interface. ·      Delete all MAC address entries of the interface.

 

Configuration restrictions and guidelines

·          To use loopback detection on an Ethernet interface, you must enable the function both globally and on the interface.

·          To disable loopback detection on all interfaces, run the undo loopback-detection enable command in system view.

·          To enable a hybrid or trunk port to take the administratively specified protective action, you must use the loopback-detection control enable command on the port.

·          When you change the link type of an Ethernet interface by using the port link-type command, the switch removes the protective action configured on the interface. For more information about the port link-type command, see Layer 2—LAN Switching Command Reference.

Configuration procedure

To configure loopback detection:

 

Step	Command	Remarks
1.       Enter system view.	system-view	N/A
2.       Enable global loopback detection.	loopback-detection enable	By default, global loopback detection is disabled.
3.       Enable multi-port loopback detection.	loopback-detection multi-port-mode enable	Optional. By default, multi-port loopback detection is disabled, and the device can only detect single-port loopback.
4.       Set the loopback detection interval.	loopback-detection interval-time time	Optional. The default setting is 30 seconds.
5.       Enter Ethernet interface view or port group view.	·      Enter Ethernet interface view: interface interface-type interface-number ·      Enter port group view: port-group manual port-group-name	Use one of the commands. To configure loopback detection on one interface, enter Ethernet interface view. To configure loopback detection on a group of Ethernet interfaces, enter port group view.
6.       Enable loopback detection on the interface.	loopback-detection enable	By default, loopback detection is disabled.
7.       Enable loopback detection control on a trunk port or a hybrid port.	loopback-detection control enable	Optional. By default, loopback detection control is disabled.
8.       Enable loopback detection in all the VLANs on the trunk or hybrid port.	loopback-detection per-vlan enable	Optional. By default, a trunk or hybrid port performs loopback detection only in its PVID.
9.       Set the protective action to take on the interface when a loop is detected.	loopback-detection action { no-learning | semi-block | shutdown }	Optional. By default, when a loop is detected on an interface, the interface does not receive or send packets, and the system generates traps and log messages and deletes all MAC address entries of the interface. With the shutdown keyword specified, the looped port is automatically shut down and its physical state changes to Loop down. After the loop is removed, use the undo shutdown command on the port to recover its forwarding capability.

 

Setting the MDI mode of an Ethernet interface

IMPORTANT: Fiber ports do not support the MDI mode setting.

 

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 (MDI) modes:

·          Across mode

·          Normal mode

·          Auto mode

A copper Ethernet interface uses an RJ-45 connector, which comprises eight pins, each of which plays a dedicated role. For example, pins 1 and 2 transmit signals, and pins 3 and 6 receive signals. The pin role varies by the MDI modes as follows:

·          In normal mode, pins 1 and 2 are transmit pins, and pins 3 and 6 are receive pins.

·          In across mode, pins 1 and 2 are receive pins, and pins 3 and 6 are transmit pins.

·          In auto mode, the interface negotiates pin roles with its peer.

To enable the interface to communicate with its peer, make sure that its transmit pins are connected to the remote receive pins. If the interface can detect the connection cable type, set the interface in auto MDI mode. If not, set its MDI mode by using the following guidelines:

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

·          When a crossover cable is used, set the interface to operate in the same MDI mode as its peer, or set either end to operate in auto mode.

To set the MDI 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 MDI mode of the Ethernet interface.	mdi { across | auto | normal }	By default, a copper Ethernet interface operates in auto mode to negotiate pin roles with its peer.

 

Enabling bridging on an Ethernet interface

When an incoming packet arrives, the device processes the packet in the following workflow:

·          If the packet is a known packet (such as a unicast or multicast packet), the switch looks up the destination MAC address of the packet in the MAC address table. If an entry is found, but the outgoing interface is the same as the receiving interface, the device discards the packet.

·          If the packet is an unknown packet, the WX5540E switching engine broadcasts the packets to any interface other than the receiving interface.

The process above indicates that the receiving interface of a packet cannot be the outgoing interface of the packet at the same time. To enable the device to forward such packets rather than drop them in this case, enable the bridging function on the Ethernet interface.

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.

 

Testing the cable connection of an Ethernet interface

IMPORTANT: ·      Fiber ports do not support this feature. ·      If the link of an Ethernet port is up, testing its cable connection will cause the link to come down and then go up.

 

You can test the cable connection of an Ethernet interface for a short or open circuit. The device displays cable test results within five seconds. If any fault is detected, the test results include the length of the faulty cable segment.

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.       Test the cable connected to the Ethernet interface.	virtual-cable-test

 

Configuring storm control on an Ethernet interface

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 a higher threshold.

For management purposes, you can configure the interface to send threshold event traps and log messages when monitored traffic exceeds the upper threshold or falls below the lower threshold from the upper threshold.

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

·          Blocks this type of traffic, while forwarding 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 port begins to forward the traffic.

·          Shuts down automatically. The interface shuts down automatically and stops forwarding any traffic. When the blocked traffic is detected dropping below the lower threshold, the port does not forward the traffic. To bring up the interface, use the undo shutdown command or disable the storm control function.

Alternatively, you can configure the storm suppression function to control a specific type of traffic. Do not enable them both on an Ethernet interface at the same time because the storm suppression and storm control functions are mutually exclusive. For example, with an unknown unicast suppression threshold set on an Ethernet interface, do not enable storm control for unknown unicast traffic on the interface. For more information about storm suppression, see "Configuring storm suppression."

Configuration guidelines

·          For network stability, use the default or set a higher traffic polling interval.

·          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.

·          The storm control function allows you to set the upper and lower thresholds for all three types of packets separately on the same interface.

Configuration procedure

To configure storm control on an Ethernet interface:

 

Step	Command	Remarks
1.       Enter system view.	system-view	N/A
2.       Set the traffic polling interval of the storm control module.	storm-constrain interval seconds	Optional. The default setting is 10 seconds.
3.       Enter Ethernet interface view.	interface interface-type interface-number	N/A
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 } 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 }	Optional. No action is taken on an Ethernet interface when a type of traffic exceeds the upper storm control threshold.
6.       Enable the interface to send storm control threshold event traps.	storm-constrain enable trap	Optional. By default, the interface sends traps when monitored traffic exceeds the upper threshold or drops below the lower threshold from the upper threshold.
7.       Enable the interface to log storm control threshold events.	storm-constrain enable log	Optional. By default, the interface outputs log messages when monitored traffic exceeds the upper threshold or falls below the lower threshold from the upper threshold.

 

Displaying and maintaining an Ethernet interface

Task	Command	Remarks
Display Ethernet interface information.	display interface [ interface-type ] brief [ down ] [ | { begin | exclude | include } regular-expression ] display interface interface-type interface-number [ brief ] [ | { begin | exclude | include } regular-expression ]	Available in any view.
Display traffic statistics for the specified interfaces.	display counters { inbound | outbound } interface [ interface-type ] [ | { begin | exclude | include } regular-expression ]	Available in any view.
Display traffic rate statistics over the last sampling interval.	display counters rate { inbound | outbound } interface [ interface-type ] [ | { begin | exclude | include } regular-expression ]	Available in any view.
Display information about discarded packets on the specified interfaces.	display packet-drop interface [ interface-type [ interface-number ] ] [ | { begin | exclude | include } regular-expression ]	Available in any view.
Display summary information about discarded packets on all interfaces.	display packet-drop summary [ | { begin | exclude | include } regular-expression ]	Available in any view.
Display information about the loopback function.	display loopback-detection [ | { begin | exclude | include } regular-expression ]	Available in any view.
Display information about storm control.	display storm-constrain [ broadcast | multicast | unicast ] [ interface interface-type interface-number ] [ | { begin | exclude | include } regular-expression ]	Available in any view.
Clear the interface statistics.	reset counters interface [ interface-type [ interface-number ] ]	Available in user view.
Clear the statistics of discarded packets on the specified interfaces.	reset packet-drop interface [ interface-type [ interface-number ] ]	Available in user view.