Usage Scenario

The am isolate command isolates interfaces unidirectionally. For example, if interface A is isolated from interface B unidirectionally, packets sent from interface A cannot reach interface B, but packets sent from interface B can reach interface A. Unidirectional isolation needs to be configured in the following scenarios:

• When multiple hosts connect to different interfaces of a device and a host sends many broadcast packets to the other hosts, isolate the interface connected to the host from other interfaces unidirectionally. Then the other hosts do not receive packets from the host.
• Interfaces in a port isolation group are isolated from each other, but interfaces in different port isolation groups can communicate. To isolate interfaces in different port isolation groups, configure unidirectional isolation between these interfaces.

By default, only Layer 2 packets of the current interface are isolated from a specified interface, but Layer 3 packets are not isolated. To isolate both Layer 2 and Layer 3 packets on interfaces unidirectionally, run the port-isolate mode all command.

Precautions

An interface can be unidirectionally isolated from another type of interface. However, an interface cannot be unidirectionally isolated from itself or from the management interface. In addition, an Eth-Trunk cannot be unidirectionally isolated from its member interfaces.

An interface on the 4GE-2S, 9ES2, 4ES2G-S or 4ES2GP-S card cannot be unidirectionally isolated from an interface on other cards.

An interface on the AR100&AR120&AR150&AR160 can be isolated from a maximum of 4 interfaces unidirectionally.

An interface on the AR200, AR1200, AR2200, AR3200 and AR3600 can be isolated from a maximum of 32 interfaces unidirectionally.

Usage Scenario

In auto-negotiation mode, interfaces on both ends of a link negotiate their duplex mode. If the negotiated duplex mode is not the required one, you can run the auto duplex command to set the required duplex mode in auto-negotiation mode. For example, two interfaces on both ends support full-duplex mode and half-duplex mode. If the two interfaces negotiate to work in half-duplex mode, but they are required to work in full-duplex mode, you can run the auto duplex full command to set the full-duplex mode for the two interfaces.

Prerequisites

The Ethernet interface works in auto-negotiation mode.

Precautions

• By default, an Ethernet interface works in auto-negotiation mode, which is recommended. If the negotiation succeeds, the two interfaces work at the same duplex mode and speed. The settings of the SPEED and DUPLEX parameters and auto-negotiation mode must be the same at the local and peer ends. Otherwise, negotiation may fail. The interface auto-negotiation mode, duplex mode and speed support depend on the device.

• In auto-negotiation mode, an FE electrical interface negotiates the duplex mode with the peer device on the link.

• In auto-negotiation mode, a GE electrical interface that works at a rate of 1000 Mbit/s supports the full-duplex mode. If the duplex mode is changed to half-duplex, the GE electrical interface works at a maximum rate of 100 Mbit/s.

Usage Scenario

In auto-negotiation mode, interfaces on both ends of a link negotiate their rate. If the negotiated rate is not the required one, run the auto speed command to set the auto-negotiation rate range to limit the negotiated rate. For example, if two interfaces negotiate to work at a rate of 1000 Mbit/s, but they are required to work at a rate of 100 Mbit/s, you can run the auto speed 100 command to set the rate of the interfaces to 100 Mbit/s.

By default, an Ethernet interface works in auto-negotiation mode, which is recommended. If the negotiation succeeds, the two interfaces work at the same duplex mode and speed. The settings of the SPEED and DUPLEX parameters and auto-negotiation mode must be the same at the local and peer ends. Otherwise, negotiation may fail. The interface auto-negotiation mode, duplex mode and speed support depend on the device.

Prerequisites

The Ethernet interface works in auto-negotiation mode. For details, see negotiation auto.

Usage Scenario

A combo interface on a router is connected to an Ethernet interface that supports the clock function on the peer end. To exchange data successfully, interfaces on the two communicating parties must work in clock synchronization state.

A combo interface works in either of the following clock modes:

• Master: uses clock signals provided by the interface card.
• Slave: uses line clock signals.

When a router is connected to an Ethernet interface on the peer end and both the connected interfaces support the clock function, you must configure the interfaces to work in master and slave clock modes respectively.

• When you manually specify the clock modes of the two interfaces, you must configure one interface to work in master clock mode and the other in slave clock mode.
• When you manually specify the clock mode of an interface and configure the other interface to automatically select the clock mode, the other interface will automatically select the clock mode opposite to the specified the clock mode of the peer interface.
• When you configure both the interfaces to automatically select the clock mode, the interfaces will select different clock modes.

Precautions

• When the peer Ethernet interface does not support the clock function, you do not need to configure the clock mode for the combo interface.

Usage Scenario

Combo interfaces are logic interfaces. One combo interface can work as a GE electrical interface or a GE optical interface. Each combo interface has only one internal forwarding interface. When the electrical interface is enabled, the optical interface is disabled. When the optical interface is enabled, the electrical interface is disabled. Set the working mode of combo interfaces according to network requirements. The electrical and optical interfaces of a combo interface use the same interface view. You can enable the electrical or optical interface, and configure interface attributes such as the rate and duplex mode in the same interface view.

Precautions

This command takes effect only on combo interfaces.

If a combo interface is configured to work in a different mode from the remote interface, the two interfaces cannot communicate.

When a combo interface works in auto mode, to modify the configuration of the electrical or optical interface, you must forcibly configure the combo interface to work in electrical or optical mode.

If you have specified the interface attributes (such as auto-negotiation mode, rate, and duplex mode) on a combo interface, the system may automatically generate the port media type fiber and port media type copper configurations to determine whether an interface configuration item belongs to the optical interface or electrical interface. If the combo interface works in one mode (such as the electrical mode), the configuration for the other mode (such as the optical mode) will not be lost.

When the combo interface of the AR531 series works in optical mode, the interface supports only the non-auto-negotiation mode, and the peer interface must also be configured to work in non-auto-negotiation mode.

For example, after you run the display this command on a combo interface, the interface configuration is as follows:

#  
interface GigabitEthernet0/0/0
 ip address 192.168.1.10 255.255.255.0
 port media type fiber        
  undo negotiation auto        
  speed 100                    
 port media type copper          
  undo negotiation auto        
 combo-port fiber
#    

The command output shows that there are two configuration items undo negotiation auto and speed 100 when the combo interface works as an optical interface and one configuration item undo negotiation auto when the combo interface works as an electrical interface.

Usage Scenario

The auto recovery function is configured and the delay for the an interface to change from Down to Up is set using the error-down auto-recovery command. If the interface is in the error-down state, you can run the display error-down recovery command to view the remaining time for the Up event.

Prerequisites

The auto recovery function has been configured on an interface using the error-down auto-recovery command.

Precautions

If interface is not specified in this command, the system displays information about all interfaces in error-down state.

Usage Scenario

You can use the display interface ethernet brief command to view brief information about Ethernet interfaces, including the physical status, auto-negotiation mode, duplex mode, bandwidth, and average inbound and outbound bandwidth usages within the last period of time. This information helps you locate and rectify faults.

Precautions

To clear statistics on an interface, run the reset counters interface command.

The port isolation feature isolates interfaces in a VLAN. By adding interfaces to a port isolation group, you can implement Layer 2 isolation between these interfaces. To view the configuration of the port isolation group, run the display port-isolate group command.

Usage Scenario

The Simple Network Management Protocol (SNMP) is a network management standard widely used on the TCP/IP network. It uses a central computer (a network management station) that runs network management software to manage network elements. The SNMP agent reports trap messages to the network management station so that the network management station can obtain the network status in a timely manner, and the network administrator can take measures accordingly.

Prerequisites

SNMP has been enabled. See snmp-agent.

Usage Scenario

Prerequisites

The interface works in non-auto negotiation mode.

Precautions

A GE electrical interface that works at 1000 Mbit/s supports only the full-duplex mode. A GE electrical interface and its peer interface do not need to negotiate the duplex mode.

By default, an Ethernet interface works in auto-negotiation mode, which is recommended. If the negotiation succeeds, the two interfaces work at the same duplex mode and speed. The settings of the SPEED and DUPLEX parameters and auto-negotiation mode must be the same at the local and peer ends. Otherwise, negotiation may fail. The interface auto-negotiation mode, duplex mode and speed support depend on the device.

Usage Scenario

You can run the encapsulation priority-tagged dot1p priority-value command to configure the outbound interface to add a VLAN tag of VLAN 0 to packets and sets the 802.1p priority of protocol packets.

In the bridge scenario, you can run the encapsulation priority-tagged dot1p-transmit priority-value command to configure the outbound interface to add a VLAN tag of VLAN 0 to packets and sets the 802.1p priority of data packets.

Prerequisites

Run the undo ip soft-forward enhance enable command in the system view to disable the enhanced forwarding function for control packets generated by the device.

Precautions

The encapsulation priority-tagged dot1p priority-value command can be used only on Layer 3 Ethernet interfaces, GE interfaces, XGE interfaces, VE interfaces.

The encapsulation priority-tagged dot1p-transmit priority-value command can be used only on Layer 3 Ethernet interfaces, GE interfaces, XGE interfaces.

The encapsulation priority-tagged dot1p-transmit priority-value command takes effect only in bridge scenarios.

Usage Scenario

By default, an interface can only be resumed by a network administrator after being shut down. To configure the interface to restore to the Up state automatically, run the error-down auto-recovery command to set an auto recovery delay. After the delay, the interface goes Up automatically.

The restored interface is shut down again if the interface receives BPDUs again or the link is considered unavailable in a specified time.

Precautions

The error-down auto-recovery command is invalid for the interface that has been in error-down state. It takes effect for only the interface that enters the error-down state after the error-down auto-recovery command is executed.

BPDU protection has been enabled using the stp bpdu-protection command in the system view.

A threshold crossing event has been associated with an interface using the efm threshold-event trigger error-down command in the interface view. An error event has been associated with an interface using the efm trigger error-down command in the interface view.

Usage Scenario

When an Ethernet interface that has the backup link configured receives error packets, packet loss occurs. To ensure that services are running properly, the interface transits to the error-down state and services are switched to the backup link when the number of error packets received on the interface reaches the alarm threshold.

Follow-up Procedure

By default, an interface that transits to the error-down state can only be restored manually using the undo shutdown command. To configure the interface to restore to the Up state automatically, run the error-down auto-recovery cause error-statistics command in the system view to set a recovery delay. After the delay, the interface goes Up automatically.

Usage Scenario

Network congestion causes packet loss. Flow control is a method to prevent packet loss. If network congestion occurs on the local device, the local device sends a message to the remote device, instructing the remote device to reduce the packet sending rate. After receiving the message, the remote device reduces its packet sending rate, which prevents congestion.

Precautions

• If flow control is enabled on an interface, it must also be enabled on the peer interface.

• If the flow-control negotiation command has been executed on an Ethernet interface to enable flow control auto-negotiation, running the flow-control command on the interface will fail.

Usage Scenario

Network congestion causes packet loss. Flow control can prevent packet loss. If congestion occurs on a device, the device sends a message to request the peer device to stop sending packets, which prevents packet loss. Flow control auto-negotiation enables a device to determine whether to enable flow control by negotiating with the peer device.

Prerequisites

The Ethernet interface works in auto-negotiation mode.

Precautions

• If flow control auto-negotiation is enabled on an interface, it must also be enabled on the peer interface.

• If flow control has been enabled on an Ethernet interface using the flow-control command, run the undo flow-control command to disable flow control before running the flow-control negotiation command. Otherwise, the flow-control negotiation command fails to be executed.

Usage Scenario

To perform the same configuration on multiple Ethernet interfaces, add these Ethernet interfaces to a port group and run commands in the port group view to configure the Ethernet interfaces in batches.

Prerequisites

A permanent port group has been created using the port-group command in the system view.

Precautions

• The E1-F and CE1/PRI interfaces cannot be added to the same permanent port group.

• A maximum of 32 permanent port groups are supported by the system, and a maximum of 48 interfaces can be added to a permanent port group.

• This command has the same function as the port-group group-member command that is used in the system view. You can also run the port-group group-member command to add interfaces to a temporary port group to configure the interfaces in batches.

• When you specify the keyword to in the group-member command:

  • The interfaces specified before and after the keyword to must reside on the same interface card. To add consecutive interfaces on different interface cards to the same port group, run the group-member command or use to multiple times.
  • The interfaces specified before and after the keyword to must be of the same type such as Ethernet interfaces.
  • The interfaces specified before and after the keyword to must have the same attribute. For example, both of them are main interfaces or sub-interfaces. If they are sub-interfaces, they must belong to the same main interface.
  • If to is not used, these limitations do not apply.

After enter the specified Ethernet interface view, you can set attributes for the Ethernet interface.

You can run the display device command to view the slot ID of a card to determine the value range of interface-number. Only Layer 3 Ethernet interfaces support sub-interfaces.

Usage Scenario

Generally, a device has many Ethernet interfaces and most of them have the same configuration. Configuring these Ethernet interfaces one by one increases the configuration workload and may result in incorrect configurations. Therefore, you can add the Ethernet interfaces to be configured with the same command to a port group. After a command is run in this port group, the system executes the command on all the member interfaces. This process allows Ethernet interfaces to be configured in batches.

Precautions

• The interface range and port-group group-member commands have the same functions. Therefore, use either of the commands for configuration.

• After exiting from the temporary port group view, the system deletes the temporary port group.

• The interface range command is equivalent to the group-member command executed in the permanent port group view. Multiple interfaces can be added to a permanent port group in batches using the group-member command.

• E1-F and CE1/PRI interfaces cannot be added to the same temporary port group.

• The system supports a maximum of 32 temporary port groups. If more than 32 users log in to the device through Telnet simultaneously, only 32 users can create temporary port groups.

• A temporary port group supports a maximum of 48 member interfaces.

• When you specify the keyword to in the interface range command:

  • The interfaces specified by interface-number1 and interface-number2 must reside on the same LPU. To add contiguous interfaces on different LPUs to the same port group, run this command several times or use the keyword to several times.
  • The interfaces specified by interface-number1 and interface-number2 must be of the same type, for example, both of the interfaces are Ethernet interfaces.
  • The interfaces specified before and after the keyword to must have the same attribute. For example, both of them are main interfaces or sub-interfaces. If they are sub-interfaces, they must belong to the same main interface.
  • If to is not specified, the preceding limitations do not apply.

Usage Scenario

The IFG is used to differentiate two data packets. The ifg command configures the IFG to adjust data packet forwarding efficiency.

The packet forwarding rate, also called the throughput, is the data forwarding capability on an interface, expressed in packets per second. The packet forwarding rate is calculated based on the number of 64-byte data packets sent in a certain period. The payload of the frame header and IFG affects the packet forwarding rate.

Precautions

Changing the IFG on an interface is not recommended because this may cause packet loss on the interface.

Monitoring bandwidth usage helps you learn about current device load. If the bandwidth usage exceeds a configured threshold, a log or an alarm is generated, indicating that bandwidth resources become insufficient and need an increase. For example, if bandwidth usage exceeds 95% of total bandwidth, an alarm is generated, indicating that bandwidth is exhausted. Some services may be interrupted before the bandwidth increases. To help prevent service interruption, setting two bandwidth usage thresholds, one for generating a log and the other for generating an alarm helps you increase bandwidth in time.

Outbound bandwidth usage = (Outbound interface rate/Outbound physical interface bandwidth) x 100

Inbound bandwidth usage = (Inbound interface rate/Inbound physical interface bandwidth) x 100

If the offset between the value of bandwidth-in-use and the value of resume-threshold is too small, log information may be frequently displayed.

Usage Scenario

Loopback detection can be enabled to test some special functions, for example, locating faults on the Ethernet. After loopback detection is enabled, the Ethernet interface works in full-duplex mode. After loopback detection is disabled, the original duplex mode of the Ethernet interface is restored.

After loopback detection is enabled on an interface, packets sent from the interface are sent back to this interface.

Follow-up Procedure

Run the display interface command to check whether the current status of the interface configured with internal loopback is Up. If the current status of the interface is Up, the internal forwarding function works well; otherwise, a fault occurs during internal forwarding.

Precautions

Loopback detection interrupts the operation of Ethernet interfaces and links. After loopback detection is performed, run the undo loopback command to disable loopback detection immediately.

Usage Scenario

The MAC address of an Ethernet interface is the system MAC address and may conflict with the MAC address of another interface. If the MAC address of an Ethernet interface conflicts with that of another interface, a loop may occur or traffic may fail to be forwarded.

You can run the mac-address command to change the MAC address of the Ethernet interface to ensure that service data flows are properly forwarded.

Configuration Impact

After the MAC address of an Ethernet interface is changed, the device proactively sends gratuitous ARP packets to update ARP entries on the remote device.

Precautions

This command can be configured only on Layer 3 Ethernet interfaces.

Usage Scenario

You can run the management-plane isolate enable command on the device so that the service port will discard the packets whose destination address is the management port address. This improves network security and prevents attacks between the management port through the service ports. However, the device can access the IP address of service ports from the management port.

Precautions

The management-port isolate enable and management-plane isolate enable command functions are different. The management-port isolate enable command isolates traffic between the management port and service ports by marking the network segment routes with the outbound interface being the management port as the blackhole routes, whereas the management-plane isolate enable command isolates service ports from the management port by marking the host and broadcast routes with the outbound interface being the management port as the blackhole routes.

Usage Scenario

You can run the management-port isolate enable command on the device to restrict packet traffic between the management port and service ports. That is, the packets received on the management port will not be forwarded from service ports; similarly, the packets received on service ports will not be forwarded from the management port. This improves network security and prevents attacks on the management port from service ports.

Precautions

The management-port isolate enable and management-plane isolate enable command functions are different. The management-port isolate enable command isolates traffic between the management port and service ports by marking the network segment routes with the outbound interface being the management port as the blackhole routes, whereas the management-plane isolate enable command isolates service ports from the management port by marking the host and broadcast routes with the outbound interface being the management port as the blackhole routes.

An Ethernet interface consists of eight pins. Each pin has its functions. For example, pins 1 and 2 send signals, and pins 3 and 6 receive signals. By setting the MDI mode for an interface, you can change the roles of pins in communication so that the interface adapts to the actual network cable type.

Setting the MDI mode to auto is recommended because the auto mode applies to most scenarios. When the network cable type parameters cannot be obtained, set the MDI mode to across or normal manually.

The methods to set the MDI mode manually are as follows:

• When straight-through network cables are used, the MDI modes of the interfaces on the local and peer devices must be different. For example, you can set the MDI mode of the interface on the local device to across and the MDI mode of the interface on the peer device to normal.
• When crossover network cables are used, the MDI modes of the interfaces on the local and peer devices must be the same. For example, you can set the MDI modes of the interfaces on the local and peer devices to across or normal. Alternatively, the MDI type of the interface on a device is auto and the MDI type of the interface on the other device can be set to across or normal.

Usage Scenario

Precautions

• If you run the mtu command multiple times in the same Ethernet interface view, only the latest configuration takes effect.

• This command can only be used on Layer 3 Ethernet interfaces.

Usage Scenario

Earlier Ethernet worked in 10M half-duplex mode and required mechanisms such as Carrier Sense Multiple Access (CSMA)/Collision Detection (CD) to ensure system stability. As Ethernet technology develops, full-duplex Ethernet and 100 Mbit/s Ethernet emerge. This greatly improves Ethernet performance. Auto-negotiation technology allows new Ethernet to be compatible with earlier Ethernet. In auto-negotiation mode, interfaces on both ends of a link negotiate their operating parameters, including the duplex mode and rate. If the negotiation succeeds, the two interfaces work at the same operating parameters.

Precautions

• By default, an Ethernet interface works in auto-negotiation mode, which is recommended. If the negotiation succeeds, the two interfaces work at the same duplex mode and speed. The settings of the SPEED and DUPLEX parameters and auto-negotiation mode must be the same at the local and peer ends. Otherwise, negotiation may fail. The interface auto-negotiation mode, duplex mode and speed support depend on the device.

• By default, GE interfaces do not support flow control auto-negotiation. You can run the flow-control negotiation command to configure flow control auto-negotiation.
• GE optical interfaces do not support auto-negotiation function after FE optical modules are installed on the interfaces.

When an interface becomes Down, services on the interface are interrupted even if this interface becomes Up soon. To prevent services from being interrupted, set the delay in reporting a Down event on the interface so that the system still considers that this interface is in Up state within the delay time.

Usage Scenario

Generally, a device has many interfaces and most of them have the same configuration. Configuring these interfaces one by one increases the configuration workload and may result in incorrect configurations. You can add the interfaces to be configured with the same commands to a permanent port group. After a command is run in this port group, the system executes the command on all the member interfaces. This process allows interfaces to be configured in batches.

Follow-up Procedure

Run the group-member command to add Ethernet interfaces to the created permanent port group.

Precautions

• The port-group-name parameter cannot be set to all.

• The system supports a maximum of 32 permanent port groups and each port group supports a maximum of 48 member interfaces.

Usage Scenario

Generally, a device has many Ethernet interfaces and most of them have the same configuration. Configuring these Ethernet interfaces one by one increases the configuration workload and may result in incorrect configurations. Therefore, you can add the Ethernet interfaces to be configured with the same command to a port group. After a command is run in this port group, the system executes the command on all the member interfaces. This process allows Ethernet interfaces to be configured in batches.

Precautions

• After exiting from the temporary port group view, the system deletes the temporary port group.

• The port-group group-member command is equivalent to the group-member command executed in the permanent port group view. Multiple interfaces can be added to a permanent port group in batches using the group-member command.

• E1-F and CE1/PRI interfaces cannot be added to the same temporary port group.

• The system supports a maximum of 32 temporary port groups. If more than 32 users log in to the device through Telnet simultaneously, only 32 users can create temporary port groups.

• A temporary port group supports a maximum of 48 member interfaces.

• When you specify the keyword to in the port-group group-member command:

  • The interfaces specified by interface-number1 and interface-number2 must reside on the same LPU. To add contiguous interfaces on different LPUs to the same port group, run this command several times or use the keyword to several times.
  • The interfaces specified by interface-number1 and interface-number2 must be of the same type, for example, both of the interfaces are Ethernet interfaces.
  • The interfaces specified before and after the keyword to must have the same attribute. For example, both of them are main interfaces or sub-interfaces. If they are sub-interfaces, they must belong to the same main interface.
  • If to is not specified, the preceding limitations do not apply.

Usage Scenario

To implement Layer 2 isolation between interfaces, add different interfaces to different VLANs. This, however, wastes VLAN resources. To save VLAN resources, enable port isolation to isolate interfaces in a VLAN. That is, you can add interfaces to a port isolation group to implement Layer 2 isolation between these interfaces. Port isolation provides secure and flexible networking schemes for customers.

Precautions

• After port isolation is configured, ports are isolated at Layer 2 but can communicate at Layer 3 by default. To configure both Layer 2 isolation and Layer 3 isolation, run the port-isolate mode all command.

• Interfaces in a port isolation group are isolated from each other, but interfaces in different port isolation groups can communicate. If group-id is not specified, interfaces are added to port isolation group 1 by default.

• Inter-board port isolation is not supported on the interfaces of the 4GE-2S, 9ES2, 4ES2G-S or 4ES2GP-S interface card.

• The AR100&AR120&AR150&AR160&AR200 series, AR1200 series, AR2220E, AR2201-48FE, AR2202-48FE, AR2204-51GE-P, AR2204-51GE-R, AR2204-27GE-P, AR2204-27GE, AR2204E, AR2204E-D, and AR2204 only support isolation at Layer 2 and interworking at Layer 3. GE0/0/3 to GE0/0/26 on the AR2204-51GE-P and AR2204-51GE-R cannot be isolated from GE0/0/27 to GE0/0/50.

Usage Scenario

To disable members in a port isolation group from communicating at Layer 2 but allow them to access public resources, such as printer and server, run the port-isolate mode command to set the port isolation mode to l2.

To disable members in a port isolation group from communicating at both Layer 2 and Layer 3, run the port-isolate mode command to set the port isolation mode to all.

Precautions

• To isolate ports at both Layer 2 and Layer 3, run the port-isolate mode all command.

• To isolate ports at Layer 2 but allow them to communicate at Layer 3, run the port-isolate mode l2 command.

Usage Scenario

By default, an Ethernet interface on the device works in Layer 2 mode. To enable Layer 3 functions on the interface, run the undo portswitch command on the interface.

Precautions

The minimum interval between running the portswitch and undo portswitch commands must be 30s.

Usage Scenario

The QoS function counts the inter-frame gap when calculating the traffic rate on an interface, but the traffic statistics on the interface do not contain the inter-frame gap. Therefore, the traffic statistics collected on an interface are different from the traffic statistics of rate limit on the interface. To solve this problem, configure the traffic statistics on an interface to contain the inter-frame gap.

Precautions

The device counts bytes in the inter-frame gap when collecting traffic statistics on a sub-interface. By default, the device does not count bytes in the inter-frame gap when collecting traffic statistics on a main interface. Therefore, traffic statistics on a main interface differ from those on its sub-interface. You can run the set flow-statistics include-interframe command on the main interface to configure the device to count bytes in the inter-frame gap and preamble when collecting traffic statistics on the main interface.

You can specify trap-name to enable the trap function for one or more events of the errordown module.

Usage Scenario

In non-auto negotiation mode, if interfaces on two connected devices work at different rates, use the speed command to change the rates of the interfaces to be the same so that the two devices can communicate.

By default, an Ethernet interface works in auto-negotiation mode, which is recommended. If the negotiation succeeds, the two interfaces work at the same duplex mode and speed. The settings of the SPEED and DUPLEX parameters and auto-negotiation mode must be the same at the local and peer ends. Otherwise, negotiation may fail. The interface auto-negotiation mode, duplex mode and speed support depend on the device.

If the remote interface does not support the auto negotiation mode, run the undo negotiation auto command on the local interface to configure the interface to work in non-auto negotiation mode. You can then change the rate of the local interface to be the same as the rate of the remote interface to ensure proper communication.

Usage Scenario

The bandwidth usage represents the load on a device. If the bandwidth usage exceeds the threshold, bandwidth of the device is insufficient for services and needs expansion. For example, if the bandwidth usage exceeds 95%, an alarm is generated to indicate that bandwidth resources are used up. Services may be interrupted before system expansion. You can set the upper and lower thresholds for bandwidth usage. When the bandwidth usage exceeds the lower threshold, the system generates a log. When the bandwidth usage exceeds the upper threshold, the system triggers an alarm.

Outbound bandwidth usage = (Outbound interface rate/Outbound physical interface bandwidth) x 100

Inbound bandwidth usage = (Inbound interface rate/Inbound physical interface bandwidth) x 100

The interface rate and bandwidth are expressed in bits per second.

The interval for collecting statistics on the traffic rate on an interface is the value configured using the set flow-stat interval command on the interface.

To set a lower threshold, run the log-threshold command.

Precautions

• When the bandwidth usage exceeds the threshold for generating a trap, the system generates a trap. When the bandwidth usage falls below the threshold for clearing a trap, the system clears the trap.

• If the offset between the value of bandwidth-in-use and the value of resume-threshold is too small, trap information may be frequently displayed.

• The log threshold must be lower than the trap threshold, providing efficient protection for services. For example, when the inbound bandwidth usage reaches 80%, a log is generated. If the inbound bandwidth usage continues to increase and reaches 95%, a trap is generated. This ensures that a log is generated for inbound bandwidth usage of 80%, and a trap is generated for inbound bandwidth usage of 95%. Either the log or the trap prompts for a bandwidth increase, preventing service interruption.

The system generates an alarm when the number of error packets received by an interface within an alarm interval exceeds the alarm threshold. If the number of received error packets is 0 in the next alarm interval, the system displays an alarm clearance message.

Usage Scenario

Precautions

• The distance error generated during VCT detection is about 10 m. The test result is only for reference and may be inaccurate for cables of some vendors.
• Running the virtual-cable-test command may affect services on the interface in a short period of time.
• Combo electrical interfaces support cable tests.
• Before performing a cable test, shut down the remote interface or remove the network cable from the remote interface. Otherwise, signals from the remote interface may make the test result inaccurate.