03-Layer 2—LAN Switching Configuration Guide

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03-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

Restrictions and guidelines for 25-GE interfaces· 2

Configuring common Ethernet interface settings· 2

Splitting a 100-GE interface and combining 10-GE breakout interfaces· 2

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· 5

Configuring jumbo frame support 5

Configuring physical state change suppression on an Ethernet interface· 6

Configuring dampening on an Ethernet interface· 7

Enabling link flapping protection on an interface· 8

Configuring FEC·· 9

Configuring link compensation· 10

Configuring storm suppression· 10

Configuring generic flow control on an Ethernet interface· 11

Configuring PFC·· 12

Setting PFC thresholds· 13

Configuring PFC deadlock detection· 14

Configuring the early warning thresholds for PFC packets· 16

Setting the statistics polling interval 17

Enabling loopback testing on an Ethernet interface· 17

Forcibly bringing up a fiber port 18

Configuring interface alarm functions· 19

Restoring the default settings for an interface· 21

Configuring a Layer 2 Ethernet interface· 21

Configuring storm control on an Ethernet interface· 21

Configuring a Layer 3 Ethernet interface or subinterface· 23

Setting the MTU for an Ethernet interface or subinterface· 23

Setting the MAC address of an Ethernet interface or subinterface· 23

Display and maintenance commands for Ethernet interfaces· 23

 

 


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 a management interface

A management interface uses an RJ-45/LC 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.

Ethernet interface naming conventions

When the device is in an IRF fabric, Ethernet interfaces are named in the format of interface type A/B/C/D. When the device is not in an IRF fabric, 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.

·     B—Card slot number.

·     C—Subcard slot number.

·     D—Port index.

A 10-GE or 25-GE breakout interface split from a 100-GE interface is named in the format of interface type A/B/C:D. A/B/C is the interface number of the 100-GE interface. D is the number of the 10-GE or 25-GE interface, which is in the range of 1 to 4. For information about splitting a 100-GE interface into 10-GE breakout interfaces, see "Splitting a 100-GE interface and combining 10-GE breakout interfaces." For information about splitting a 100-GE interface into 25-GE breakout interfaces, see "Splitting a 100-GE interface and combining 25-GE breakout interfaces."

Restrictions and guidelines for 25-GE interfaces

When you use the using twenty-fivegige command to split a 100-GE interface into four 25-GE breakout interfaces, the four breakout interfaces are organized into one group.

Interfaces in the same group must have the same speed settings. When you modify the speed of an interface in a group, the modification takes effect on all interfaces in the group. When you use the default command to restore the default settings for the interface, the speed will be restored to the default for the interface and the other interfaces in the group.

Configuring common Ethernet interface settings

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

Splitting a 100-GE interface and combining 10-GE breakout interfaces

About 100-GE interface splitting and 10-GE breakout interface combining

You can use a 100-GE interface as a single interface. To improve port density, reduce costs, and improve network flexibility, you can split a 100-GE interface with a split-capable transceiver module installed 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 100-GE interface HundredGigE 1/0/1 into four 10-GE breakout interfaces Ten-GigabitEthernet1/0/1:1 through Ten-GigabitEthernet1/0/1:4.

If you need higher bandwidth on a single interface, you can combine the multiple 10-GE breakout interfaces into a 100-GE interface.

 

Restrictions and guidelines for 100-GE interface splitting and 10-GE breakout interface combining

·     A 100-GE interface split into multiple 10-GE breakout interfaces must use a dedicated cable. After you combine the multiple 10-GE breakout interfaces, replace the dedicated 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.

·     Device reboot is not required for this feature to take effect. You can view the split or combined interface by using the display interface brief command.

·     To view interfaces capable of being spit, execute the display interface split-capable command.

·     When interfaces are being split or combined, you cannot reboot the MPU or perform active/standby MPU switchover.

Splitting a 100-GE interface into four 10-GE breakout interfaces

1.     Enter system view.

system-view

2.     Enter 100-GE interface view.

interface interface-type interface-number

3.     Split the 100-GE interface into four 10-GE breakout interfaces.

using tengige

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

Combining four 10-GE breakout interfaces into a 100-GE interface

1.     Enter system view.

system-view

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

interface interface-type interface-number

3.     Combine the four 10-GE breakout interfaces into a 100-GE interface.

using hundredgige

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

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

About 100-GE interface splitting and 25-GE breakout interface combining

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.

·     Device reboot is not required for this feature to take effect. You can view the combined interface by using the display interface brief command.

·     To view interfaces capable of being spit, execute the display interface split-capable command.

·     When interfaces are being split or combined, you cannot reboot the MPU or perform active/standby MPU switchover.

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

1.     Enter system view.

system-view

2.     Enter 100-GE interface view.

interface interface-type 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 interface-type 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 Ethernet interface basic settings

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

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

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

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

Restrictions and guidelines

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

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

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Set the description for the Ethernet interface.

description text

The default setting is interface-name Interface. For example, HundredGigE1/0/1 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 | 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 down state.

Configuring basic settings of an Ethernet subinterface

Restrictions and guidelines for Ethernet subinterface basic settings

Procedure

1.     Enter system view.

system-view

2.     Create an Ethernet subinterface.

interface interface-type interface-number.subnumber

3.     Set the description for the Ethernet subinterface.

description text

The default setting is interface-name Interface. For example, HundredGigE1/0/1.1 Interface.

4.     Set the expected bandwidth for the Ethernet subinterface.

bandwidth bandwidth-value

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

5.     Bring up the Ethernet subinterface.

undo shutdown

By default, Ethernet subinterfaces are in up state.

Configuring the link mode of an Ethernet interface

About the link mode of an Ethernet interface

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

Restrictions and guidelines

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

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Configure the link mode of the Ethernet interface.

port link-mode { bridge | route }

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

Configuring jumbo frame support

About jumbo frame

Jumbo frames are frames larger than 1536 bytes and are typically received by an Ethernet interface during high-throughput data exchanges, such as file transfers.

The Ethernet interface processes jumbo frames in the following ways:

·     When the Ethernet interface is configured to deny jumbo frames (by using the undo jumboframe enable command), the Ethernet interface discards jumbo frames.

·     When the Ethernet interface is configured with jumbo frame support, the Ethernet interface performs the following operations:

¡     Processes jumbo frames within the specified length.

¡     Discards jumbo frames that exceed the specified length.

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Configure jumbo frame support.

jumboframe enable [ size ]

By default, the device allows jumbo frames within 9416 bytes to pass through.

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

Configuring physical state change suppression on an Ethernet interface

About physical state change suppression

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

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

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

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

Restrictions and guidelines

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

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

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

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

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

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

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Configure physical state change suppression.

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

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

Configuring dampening on an Ethernet interface

About dampening

The interface dampening feature uses an exponential decay mechanism to prevent excessive interface flapping events from adversely affecting routing protocols and routing tables in the network. Suppressing interface state change events protects the system resources.

If an interface is not dampened, its state changes are reported. For each state change, the system also generates an SNMP trap and log message.

After a flapping interface is dampened, it does not report its state changes to the CPU. For state change events, the interface only generates SNMP trap and log messages.

Parameters

·     Penalty—The interface has an initial penalty of 0. When the interface flaps, the penalty increases by 1000 for each down event until the ceiling is reached. It does not increase for up events. When the interface stops flapping, the penalty decreases by half each time the half-life timer expires until the penalty drops to the reuse threshold.

·     Ceiling—The penalty stops increasing when it reaches the ceiling.

·     Suppress-limit—The accumulated penalty that triggers the device to dampen the interface. In dampened state, the interface does not report its state changes to the CPU. For state change events, the interface only generates SNMP traps and log messages.

·     Reuse-limit—When the accumulated penalty decreases to this reuse threshold, the interface is not dampened. Interface state changes are reported to the upper layers. For each state change, the system also generates an SNMP trap and log message.

·     Decay—The amount of time (in seconds) after which a penalty is decreased.

·     Max-suppress-time—The maximum amount of time the interface can be dampened. If the penalty is still higher than the reuse threshold when this timer expires, the penalty stops increasing for down events. The penalty starts to decrease until it drops below the reuse threshold.

When configuring the dampening command, follow these rules to set the values mentioned above:

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

·     The configured suppress limit is lower than or equal to the ceiling.

·     The ceiling is lower than or equal to the maximum suppress limit supported.

Figure 1 shows the change rule of the penalty value. The lines t0 and t2 indicate the start time and end time of the suppression, respectively. The period from t0 to t2 indicates the suppression period, t0 to t1 indicates the max-suppress-time, and t1 to t2 indicates the complete decay period.

Figure 1 Change rule of the penalty value

Restrictions and guidelines

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

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

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

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Enable dampening on the interface.

dampening [ half-life reuse suppress max-suppress-time ]

By default, interface dampening is disabled on Ethernet interfaces.

Enabling link flapping protection on an interface

About link flapping protection

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

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

Restrictions and guidelines

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

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

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

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

Procedure

1.     Enter system view.

system-view

2.     Enable link flapping protection globally.

link-flap protect enable

By default, link flapping protection is disabled globally.

3.     Enter Ethernet interface view.

interface interface-type interface-number

4.     Enable link flapping protection on the Ethernet interface.

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

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

Configuring FEC

About FEC

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

Restrictions and guidelines

On the switch series, 25-GE interfaces and 100-GE interfaces support FEC. However, only 25-GE interfaces support configuring FEC at the CLI.

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

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Set the FEC mode of the Ethernet interface.

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

By default, the FEC mode of an Ethernet interface is autonegotiation.

Configuring link compensation

About link compensation

As the signal transmission rate or frequency increases, high frequency components in signals attenuate more severely. For signal transmission performance, common signal compensation technologies such as pre-emphasis and equalization are introduced. Pre-emphasis amplifies high frequency components but increases the probability of crosstalk. Equalization is introduced to filter out high frequency crosstalk on the receiving end.

Link compensation enables the sending and receiving ends to exchange pre-emphasis and equalization parameters through frames. This feature improves the performance of pre-emphasis and equalization.

Restrictions and guidelines

Only 25-GE Ethernet interfaces connected through copper cables support this command. For 25-GE interfaces connected through copper cables to operate properly, you must enable link compensation.

You must enable or disable link compensation on both interfaces of a link.

Typically, the link compensation status is controlled by the software, and do not adjust the link compensation status as a best practice. Use this command to adjust the link compensation status only when the interface cannot come up.

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Configure link compensation on the interface.

port training { disable | enable }

By default, link compensation is disabled on an interface.

Configuring storm suppression

About storm suppression

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

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

Restrictions and guidelines

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

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

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

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

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

·     Set the same type of thresholds for each interface.

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

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

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

By default, broadcast suppression is disabled.

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

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

By default, multicast suppression is disabled.

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

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

By default, unknown unicast suppression is disabled.

Configuring generic flow control on an Ethernet interface

About generic flow control

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

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

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

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

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

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

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

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

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Enable generic flow control.

¡     Enable TxRx-mode generic flow control.

flow-control

¡     Enable Rx-mode generic flow control.

flow-control receive enable

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

Configuring PFC

About PFC

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

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

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

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

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

Restrictions and guidelines

·     You can configure PFC in both system view and Ethernet interface view. If you configure PFC in system view and Ethernet interface view multiple times, the most recent configuration takes effect.

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

·     To perform PFC on an IRF port, configure PFC on the IRF port and the IRF physical ports that are bound to the IRF port. For information about IRF, see IRF configuration Guide.

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

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

·     If you 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.

Configuring PFC on inner interfaces

1.     Enter system view.

system-view

2.     Enable PFC on inner interfaces.

priority-flow-control inner-port enable

By default, PFC is disabled on inner interfaces.

An inner interface is the inner Ethernet interface through which a card communicates with the device, and is invisible to users.

3.     Enable PFC for 802.1p priorities on inner interfaces.

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

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

Configuring PFC in system view

1.     Enter system view.

system-view

2.     Enable PFC on all Ethernet interfaces.

priority-flow-control enable

By default, PFC is disabled on all Ethernet interfaces.

3.     Enable PFC for 802.1p priorities on all Ethernet interfaces.

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

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

Configuring PFC in Ethernet interface view

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Enable PFC on the Ethernet interface.

priority-flow-control enable

By default, PFC is disabled on an Ethernet interface.

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.

Setting PFC thresholds

About PFC thresholds

The storage spaces for an interface include the following types:

·     Headroom storage space.

·     Shared storage space.

·     Guaranteed storage space.

Setting PFC thresholds enables flexible control over PFC and can make good use of the storage spaces. The device supports the following PFC thresholds:

·     Headroom buffer threshold—Maximum number of cell resources that can be used by packets with a specific 802.1p priority value in a headroom storage space. An interface drops received packets once this threshold is reached.

·     Back pressure frame triggering threshold—Maximum number of cell resources that can be used by packets with a specific 802.1p priority value in a shared storage space. PFC is triggered once this threshold is reached. The back pressure frame triggering threshold includes the following types:

¡     Dynamic back pressure frame triggering threshold—Maximum cell resources set in percentage.

¡     Static back pressure frame triggering threshold—Maximum cell resources set in an absolute value.

·     Offset between the back pressure frame stopping threshold and triggering threshold—When the number of cell resources used by packets with a specific 802.1p priority value decreases by this offset after PFC is triggered, PFC will be stopped.

·     PFC reserved threshold—Number of cell resources reserved for packets with a specific 802.1p priority value in a guaranteed storage space.

Restrictions and guidelines

WARNING

WARNING!

After PFC is enabled for 802.1p priorities, the PFC thresholds use the default values, which are adequate in typical network environments. As a practice, change the thresholds only when necessary.

 

You must enable PFC for 802.1p priorities before setting the PFC thresholds.

If you cancel PFC threshold settings on an interface, the PFC thresholds are restored to the state when only the priority-flow-control no-drop dot1p command is executed.

This feature does not support preprovisioning. For more information about preprovisioning, see Fundamentals Configuration Guide.

Procedure

1.     ‍Enter system view.

system-view

2.     Set the maximum number of cell resources in a headroom storage space.

priority-flow-control poolID pool-number headroom headroom-number

By default, the maximum number of cell resources in a headroom storage space is 12288.

3.     Enter Ethernet interface view.

interface interface-type interface-number

4.     Set the headroom buffer threshold.

priority-flow-control dot1p dot1p headroom headroom-number

By default, the headroom buffer threshold is 8192.

5.     Set the back pressure frame triggering threshold.

¡     Set the dynamic back pressure frame triggering threshold.

priority-flow-control dot1p dot1p ingress-buffer dynamic ratio

By default, no dynamic back pressure frame triggering thresholds are set.

¡     Set the static back pressure frame triggering threshold.

priority-flow-control dot1p dot1p ingress-buffer static threshold

By default, the static back pressure frame triggering threshold is 512.

6.     Set the offset between the back pressure frame stopping threshold and triggering threshold.

priority-flow-control dot1p dot1p ingress-threshold-offset offset-number

By default, the offset between the back pressure frame stopping threshold and triggering threshold is 48.

7.     Set the PFC reserved threshold.

priority-flow-control dot1p dot1p reserved-buffer reserved-number

By default, the PFC reserved threshold is 6.

Configuring PFC deadlock detection

About PFC deadlock detection

When packets carrying the specified 802.1p priority are transmitted in a loop, packets in the data buffer cannot be forwarded and PFC frames are repeatedly transmitted between devices. As a result, the cell resources in the buffer for device interfaces always cannot be released. In this case, the device enters the PFC deadlock state.

This feature periodically detects whether the device is in the PFC deadlock state. If an interface is always in the PFC XOFF state within the PFC deadlock detection interval, the device enters the PFC deadlock state. If PFC deadlock detection is recovered in automatic mode, the device automatically releases the deadlock state and recovers PFC and PFC deadlock detection after the delay timer expires. During the delay timer period, the device disables PFC and PFC deadlock detection on the interface, so that packets can be forwarded properly.

After the PFC deadlock state is released, the PFC deadlock detection feature can be recovered on the interface in automatic or manual mode. Recovering this feature enables the PFC feature again at the same time. Use the automatic recovery mode when no serious failures occur.

When a packet loop cannot be eliminated and the device enters PFC deadlock state frequently, manually recover PFC deadlock detection on the interface as follows:

1.     Perform troubleshooting and set the manual recovery mode for PFC deadlock detection.

2.     Execute the priority-flow-control deadlock recover command to recover the PFC deadlock detection and PFC features.

Restrictions and guidelines

The specified CoS value must be within the 802.1p priority list specified by using the priority-flow-control no-drop dot1p command. To view the 802.1p priority for each CoS value, execute the display qos map-table dot1p-lp command.

Prerequisites

Before you configure PFC deadlock detection on an Ethernet interface, complete the following tasks:

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

·     Enable PFC for 802.1p priorities on the Ethernet interface.

Procedure

1.     Enter system view.

system-view

2.     Set the precision for the PFC deadlock detection timer.

In standalone mode:

priority-flow-control deadlock slot slot-number precision { high | normal | low }

In IRF mode:

priority-flow-control deadlock chassis chassis-number slot slot-number precision { high | normal | low }

By default, the PFC deadlock detection timer uses normal precision.

3.     Set the PFC deadlock detection interval for the specified CoS value.

In standalone mode:

priority-flow-control deadlock slot slot-number cos cos-value interval interval

In IRF mode:

priority-flow-control deadlock chassis chassis-number slot slot-number cos cos-value interval interval

By default, the PFC deadlock detection interval is not set.

4.     Configure the delay timer for PFC deadlock detection automatic recovery.

In standalone mode:

priority-flow-control deadlock auto-recover slot slot-number cos cos-value delay delay-time

In IRF mode:

priority-flow-control deadlock auto-recover chassis chassis-number slot slot-number cos cos-value delay delay-time

By default, the delay timer for PFC deadlock detection automatic recovery is not configured.

5.     Configure the action to take on packets during the delay timer period for PFC deadlock automatic recovery.

priority-flow-control deadlock auto-recover action { discard | forwarding }

By default, the device forwards received data packets during the delay timer period for PFC deadlock detection automatic recovery.

6.     Configure the upper threshold for PFC deadlock times during the specified period.

In standalone mode:

priority-flow-control deadlock threshold slot slot-number cos cos-value period period count count

In IRF mode:

priority-flow-control deadlock threshold chassis chassis-number slot slot-number cos cos-value period period count count

By default, the upper threshold for PFC deadlock times during the specified period is not configured.

7.     Enter Ethernet interface view.

interface interface-type interface-number

8.     Set the recovery mode for PFC deadlock detection on the Ethernet interface.

priority-flow-control deadlock recover-mode { auto | manual }

By default, PFC deadlock detection recovers in automatic mode.

9.     Enable PFC deadlock detection on the Ethernet interface.

priority-flow-control deadlock enable

By default, PFC deadlock detection is disabled.

10.      (Optional.) Recover PFC deadlock detection on the Ethernet interface.

priority-flow-control deadlock recover

You can use only this command to recover PFC deadlock detection if you set the manual recovery mode for PFC deadlock detection on the Ethernet interface.

Configuring the early warning thresholds for PFC packets

About the early warning thresholds for PFC packets

You can configure the early warning threshold for incoming or outgoing PFC packets of an interface as needed. The early warning threshold notifies a situation where the PFC packet transmission rate is still within a normal range but needs attention.

When the rate of PFC packets that an interface sends or receives reaches the early warning threshold, the system generates traps and logs to notify the user. According to the traps and logs, the user can discover some exceptions in the network, for example:

·     The NIC of the peer device fails and continuously sends PFC packets at a high speed. In this case, you can set the early warning threshold for incoming PFC packets.

·     The device fails and continuously sends PFC frames. In this case, you can set the early warning threshold for outgoing PFC packets.

To monitor bidirectional PFC packets, you can set the early warning thresholds for incoming packets and outgoing packets separately.

Restrictions and guidelines

The number of PFC pause frames that an interface sends or receives is counted and the early warning threshold configuration takes effect only when PFC is enabled.

Procedure

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Configure the early warning threshold for incoming PFC packets.

priority-flow-control early-warning dot1p dot1p-list inpps pps-value

By default, no early warning threshold is configured for incoming PFC packets.

4.     Configure the early warning threshold for outgoing PFC packets.

priority-flow-control early-warning dot1p dot1p-list outpps pps-value

By default, no early warning threshold is configured for outgoing PFC packets.

Setting the statistics polling interval

About statistics polling interval

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

Setting the statistics polling interval in Ethernet interface view

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

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

flow-interval interval

By default, the statistics polling interval is 300 seconds.

Enabling loopback testing on an Ethernet interface

About loopback testing

 

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

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.

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 internal

Forcibly bringing up a fiber port

About forcibly bringing up a fiber port

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

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

Figure 2 Forcibly bring up a fiber port

Restrictions and guidelines

·     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.

Configuring interface alarm functions

About interface alarm functions

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

Restrictions and guidelines

You can configure the error packet alarm parameters in system view and interface view.

·     The configuration in system view takes effect on all interfaces. The configuration in interface view takes effect only on the current interface. (Devices that do not support the slot keyword.)

·     The configuration in system view takes effect on all interfaces of the specified slot. The configuration in interface view takes effect only on the current interface. (Devices that support the slot keyword.)

·     For an interface, the configuration in interface view takes priority, and the configuration in system view is used only when no configuration is made in interface view.

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

Enabling interface alarm functions

1.     Enter system view.

system-view

2.     Enable alarm functions for the interface monitoring module.

snmp-agent trap enable ifmonitor { crc-error | input-error | output-error } *

By default, all alarm functions are enabled for interfaces.

Configuring CRC error packet parameters

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

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

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

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

Configuring input error packet alarm parameters

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

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

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

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

Configuring output error packet alarm parameters

1.     Enter system view.

system-view

2.     Enter Ethernet interface view.

interface interface-type interface-number

3.     Configure output error packet alarm parameters.

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

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

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 storm control

Storm control compares broadcast, multicast and unknown unicast traffic regularly with their respective traffic thresholds on an Ethernet interface. For each type of traffic, storm control provides a lower threshold and an upper threshold.

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

·     Blocks this type of traffic and forwards other types of traffic—Even though the interface does not forward the blocked traffic, it still counts the traffic. When the blocked traffic drops below the lower threshold, the interface begins to forward the traffic.

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

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

·     Exceeds the upper threshold.

·     Drops below the lower threshold.

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.

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.

Setting the MAC address of an Ethernet interface or subinterface

About Layer 3 Ethernet interface MAC address

In a network, when the Layer 3 Ethernet interfaces or subinterfaces of different devices have the same MAC address, the devices might fail to communicate correctly. To eliminate the MAC address conflicts, use the mac-address command to modify the MAC addresses of Layer 3 Ethernet interfaces or subinterfaces.

Procedure

1.     Enter system view.

system-view

2.     Enter interface view.

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

3.     Set the interface MAC address.

mac-address mac-address

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

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

Display and maintenance commands for Ethernet interfaces

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.

(In standalone mode.)

display ethernet statistics slot slot-number

(In IRF mode.)

display ethernet statistics chassis chassis-number slot slot-number

Display the operational and status information of the specified interfaces.

display interface [ interface-type [ interface-number | interface-number.subnumber ] ] [ brief [ description | down ] ]

Display the operational and status information of interfaces except subinterfaces.

display interface [ interface-type ] [ brief [ description | down ] ] main

Display the status and packet statistics of interfaces.

display interface link-info [ main ]

Display interfaces capable of being split.

display interface split-capable [ slot slot-number ]

Display information about link flapping protection on interfaces.

display link-flap protection [ interface interface-type [ interface-number ] ]

Display information about dropped packets on the specified interfaces.

display packet-drop { interface [ interface-type [ interface-number ] ] | summary }

Display PFC information on the specified interfaces.

display priority-flow-control interface [ interface-type [ interface-number ] ]

Display information about storm control on the specified interfaces.

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

Clear interface statistics.

reset counters interface [ interface-type [ interface-number ] ]

Clear the Ethernet module statistics.

(In standalone mode.)

reset ethernet statistics [ slot slot-number ]

(In IRF mode.)

reset ethernet statistics [ chassis chassis-number slot slot-number ]

Clear the statistics of dropped packets on the specified interfaces.

reset packet-drop interface [ interface-type [ interface-number ] ]

 

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