S1720&S2700&S3700&S5700&S6700 Series Switches Product Troubleshooting - Preliminary-8 Interface Faults

Latest reply: Sep 26, 2017 11:33:41 778 1 0 0

8  Interface Faults

8.1  An Ethernet Interface Is Physically Down

Fault Description

An Ethernet interface is physically Down.

Possible Causes

  • Devices on both ends are powered off or the cables between the devices are not properly connected.
  • The Ethernet interface is manually shut down.
  • The twisted pair or fiber connected to the interface is too long or the fiber attenuation is high.
  • The local and remote interfaces work at different duplex modes, rates, and negotiation modes.
  • The local and remote interfaces have different training configurations.
  • The local and remote interfaces, interface modules, or devices are faulty.

Troubleshooting Procedure

  1. Check whether the local and remote devices are powered on and whether the cable and interface modules are installed properly.

    Check the cable connection.
    • Check whether the cable is loose or damaged.
    • Check whether any wires in the cable are damaged.
    Ensure that the interface can work properly.
    • Check whether the metal reed of the interface is bent or deviates.
    • Run the loopback internal command in the interface view to configure loopback detection on the interface.

    If the interfaces are still Down after the devices are powered on and connected properly, go to step 2.

  2. Check whether the interfaces have been manually shut down.

    Run the interface interface-type interface-number command in the system view to enter the interface view, and then run the display this command to check the interface configuration. If the interface has been shut down using the shutdown command, run the undo shutdowncommand in the interface view.

    c48d8beb4c7b4fdc9b5ae05191af9ca6 NOTE:

    If a Monitor Link group is configured on the device, all downlink interfaces in the group are shut down when the uplink interface is deleted from the group or becomes Down. If the uplink interface becomes Down, rectify the fault on the uplink interface.

    If the fault persists, go to step 3.

  3. Check whether the two interfaces have the same duplex mode, rate, and negotiation mode.

    Run the display interface command on the two interfaces to check the rates, duplex modes, and negotiation modes of the interfaces.

    Check Item

    Description

    Follow-up Procedure

    NegotiationAuto-negotiation mode of the interface:
    • ENABLE: indicates that the interface works in auto-negotiation mode.
    • DISABLE: indicates that the interface works in non-auto-negotiation mode.

    The two interfaces must work in the same negotiation mode. Run the negotiation auto command in the interface view to enable auto negotiation on the interfaces. If the fault persists, disable auto negotiation and forcibly set the same rate and duplex mode on the interfaces.

    Speed

    Current rate of the interface.

    If the rates of the interfaces are different in non-auto-negotiation mode, run the speed command in the interface view to set the same rate on the two interfaces.

    Duplex

    Duplex mode of the interface.

    If the duplex modes of the interfaces are different in non-auto-negotiation mode, run the duplex command in the interface view to set the same duplex mode on the two interfaces.

    Mdi
    Network cable type supported by the interface:
    • across: indicates that the interface can use a crossover cable.
    • auto: indicates that the interface automatically identifies the network cable type. That is, the interface can connect to a straight-through cable or a crossover cable.
    • normal: indicates that the interface can use a straight-through cable.

    The two interfaces must support the same network cable type. By default, an interface works in auto mode. If the interfaces do not work in this mode, run the mdi command in the interface view to change the mode to auto on the two interfaces.

    If the fault persists, go to step 4.

  4. Check whether the interface modules and the link between the interfaces work properly.

    If the two interfaces are connected by a twisted pair, check the following items.

    Check Item

    Expected Result

    Follow-up Procedure

    Twisted pair working status

    The tester shows that the twisted pair works properly.

    If the twisted pair is faulty, replace it.

    Twisted pair length

    The twisted pair length does not exceed 100 m.

    NOTE:

    The 10/100/1000M electrical interfaces use RJ45 connectors and category-5 or higher twisted pairs. The maximum transmission distance of such cables is 100 m.

    If the twisted pair length exceeds 100 m, perform either of the following operations:
    • Shorten the distance between the two devices.
    • If the distance between the two devices cannot be shortened, deploy a repeater, hub, or switch between the devices.

    Twisted pair type

    Twisted pair cables are classified into straight-through cables and crossover cables. A straight-through cable connects Ethernet interfaces between the following devices:
    • A router and a hub
    • A router and an LAN switch
    • A computer and an LAN switch
    • A computer and a hub

    A crossover cable connects Ethernet interfaces between the following devices:

    • Two routers
    • A router and a computer
    • Two hubs
    • A hub and a switch
    • Two switches
    • Two computers

    If the twisted pair type is incorrect, replace the twisted pair.

    If the two interfaces are connected by fibers, check the following items.

    Check Item

    Expected Result

    Follow-up Procedure

    Types of optical modules and fibers

    The fiber type matches the optical module type. For details about mappings between optical module types and fiber types, see Optical Module in the hardware description.

    Determine whether the fiber type matches the optical module type according to the following information:
    • A multimode fiber can be used together with multimode fiber.
    • A single-mode fiber can only be used with a single-mode optical module. A single-mode fiber is generally yellow, and a multimode fiber is generally orange.
    • Two connected optical modules must have the same wavelength.

    If the fiber type does not match the optical module type, replace the optical modules or fibers.

    Fiber length and maximum transmission distance of optical modules

    The fiber length is shorter than the maximum transmission distance of the optical modules. For the maximum transmission distance supported by different optical modules, see Optical Module in the hardware description.

    If the fiber length exceeds the maximum transmission distance of the optical modules, shorten the distance between the devices or use optical modules with a longer transmission distance.

    Optical signal attenuationThe tester shows that the optical signal attenuation is in the allowed range. For the attenuation range, see Optical Module in the hardware description.If the attenuation is high, replace the fibers. If the fault persists, shorten the distance between the devices and use shorter fibers.

    Fiber working status

    The tester shows that optical signals are sent and received correctly.

    During a loopback test, an interface is Up when both ends of a fiber are connected to the same optical module.

    If optical signals cannot be sent or received, replace the fibers. If the fault persists, replace the optical modules.

    If the fault persists, go to step 5.

  5. Check whether the two interfaces have the same training configuration. If the interfaces are 40GE interfaces, perform the following operations.

    Interface Type

    Check Criterion

    Follow-up Procedure

    40GE optical interface

    If the local and remote devices both run V200R009 or a later version, run the display this command on the interfaces to check whether there are training configurations and whether the training configurations are the same.

    If the training configurations are different, run the training (40GE interface view) command in the interface view to change the training configuration so that the two interfaces have the same training configuration.

    If one device runs a version earlier than V200R009 and the other device runs V200R009 or a later version, run the display this command on the device running V200R009 or a later version to check whether there is the training configuration.

    If the device does not have the training configuration, run the undo training enable or training disablecommand in the interface view to disable the training function.

    If the device has the training disableor undo training enableconfiguration, no action is required.

    If the local and remote devices both run a version earlier than V200R009, no action is required.

    None

    c48d8beb4c7b4fdc9b5ae05191af9ca6 NOTE:

    Only 40GE interfaces on devices running V200R009 and later versions support the training function. The function is enabled by default.

    If the fault persists, go to step 6.

  6. Check whether the local or remote device has a hardware fault.

    Connect the devices using other interfaces. If the fault persists, go to step 7.

  7. Collect the following information and contact technical support personnel:
    • Results of the preceding troubleshooting procedure
    • Configuration file, logs, and alarms of the device

8.2  An Ethernet Interface Frequently Alternates Between Up and Down States

Fault Description

An Ethernet interface frequently alternates between Up and Down states.

Possible Causes

  • The cable is not properly connected to the interface.
  • The twisted pair or fiber connected to the interface is too long or the fiber attenuation is high.
  • The local and remote interfaces work at different duplex modes, speeds, or negotiation modes.
  • The local and remote interfaces, interface modules, or devices are faulty.

Troubleshooting Procedure

  1. Check whether the cable and interface modules are properly installed on the local and remote devices.

    If the fault persists after the cable and interface modules are properly installed, go to step 2.

  2. Check whether the two interfaces have the same duplex mode, rate, and negotiation mode.

    Run the display interface command on the two interfaces to check the rates, duplex modes, and negotiation modes of the interfaces.

    Check Item

    Description

    Follow-up Procedure

    NegotiationAuto-negotiation mode of the interface:
    • ENABLE: indicates that the interface works in auto-negotiation mode.
    • DISABLE: indicates that the interface works in non-auto negotiation mode.

    The two interfaces must work in the same negotiation mode. Run the negotiation auto command in the interface view to enable auto negotiation on the interfaces. If the fault persists, disable auto negotiation and forcibly set the same rate and duplex mode on the interfaces.

    Speed

    Current rate of the interface.

    If the rates of the interfaces are different in non-auto negotiation mode, run the speed command in the interface view to set the same rate on the two interfaces.

    Duplex

    Duplex mode of the interface.

    If the duplex modes of the interfaces are different in non-auto negotiation mode, run the duplex command in the interface view to set the same duplex mode on the two interfaces.

    If the fault persists, go to step 3.

  3. Check whether the interface modules and the link between the interfaces work properly.

    If the two interfaces are connected by a twisted pair, check the following items.

    Check Item

    Expected Result

    Follow-up Procedure

    Twisted pair working status

    The tester shows that the twisted pair works properly.

    If the twisted pair is faulty, replace it.

    Twisted pair length

    The twisted pair length does not exceed 100m.

    NOTE:

    The 10/100/1000M electrical interfaces use RJ45 connectors and category-5 or higher twisted pairs. The maximum transmission distance of such cables is 100m.

    If the twisted pair length exceeds 100m, perform either of the following operations:
    • Shorten the distance between the two devices.
    • If the distance between the two devices cannot be shortened, deploy a repeater, hub, or switch between the devices.

    If the two interfaces are connected by fibers, check the following items.

    Check Item

    Expected Result

    Follow-up Procedure

    Fiber working status

    The tester shows that optical signals are sent and received correctly.

    In a loopback test, the two interfaces are Up.

    If optical signals cannot be sent or received, replace the fibers. If the fault persists, replace the optical modules.

    Types of optical modules and fibers

    The fiber type matches the optical module type. For details about mappings between optical module types and fiber types, see Optical Module in the hardware description.

    If the fiber type does not match the optical module type, replace the optical modules or fibers.

    Fiber length and maximum transmission distance of optical modules

    The fiber length is shorter than the maximum transmission distance of the optical modules. For the maximum transmission distance supported by different optical modules, see Optical Module in the hardware description.

    If the fiber length exceeds the maximum transmission distance of the optical modules, shorten the distance between the devices or use optical modules with a longer transmission distance.

    Optical signal attenuationThe tester shows that the optical signal attenuation is in the allowed range. For the attenuation range, see Optical Module in the hardware description.If the attenuation is high, replace the fibers. If the fault persists, shorten the distance between the devices and use shorter fibers.

    If the fault persists, go to step 4.

  4. Check whether the local or remote device has a hardware fault.

    Connect the twisted pair or fibers to another interface.

    If the remote device is a powered device (PD), check whether the power of the remote device exceeds the maximum power of the interface.

    c48d8beb4c7b4fdc9b5ae05191af9ca6 NOTE:

    When the instant power of the PD exceeds the maximum power of the interface, the local device powers off the PD. After a certain period, the device detects the PD and powers on it again. The PD is frequently powered on and off, so the interface alternates between Up and Down states.

    If the fault persists, go to step 5.

  5. Check the interface Up/Down log to rectify the fault.

    Up/Down Log Information

    Possible Cause

    Follow-up Procedure

    Multiple Up/Down logs are generated on the interface within a short period (60s). The interface may instantly alternate between Up and Down states.

    The remote device is restarting, so the local interface instantly alternates between Up and Down states for multiple times.

    No action is required.

    Wait until the remote device finishes restarting.

    A group of interfaces alternate between Up and Down states simultaneously.

    An active/standby switchover is performed on the remote device. When multiple interfaces of the local device connect to the same remote device, the interfaces alternate between Up and Down states simultaneously if an active/standby switchover occurs on the remote device.

    No action is required.

    Wait until the remote device finishes the active/standby switchover.

    It takes a long period for the interface to change from Down to Up.

    This log is informational. The remote device performs operations on the local interface.

    No action is required.

    The Up/Down logs are generated on the interface at different time. In this period, the interface instantly alternates between Up and Down states at an interval shorter than 1s.

    • The optical module does not match the hardware; the optical module is sensitive to the signal jitter; the receive optical power is too low.
    • The remote or local interface is faulty.

    • Port protection is configured on the remote device.

    • Replace the optical module and check whether the optical module or fiber is properly connected.
    • Connect the local interface to another remote interface.
    • Disable port protection on the remote device.

    If the fault persists, go to step 6.

  6. Collect the following information and contact technical support personnel:
    • Results of the preceding troubleshooting procedure
    • Configuration file, logs, and alarms of the device

8.3  The Auto-Negotiation Rate of an Ethernet Electrical Interface Is Incorrect

Fault Description

The following faults may occur:

  • Local and remote devices connect to each other through two electrical interfaces, and auto-negotiation is enabled on the two interfaces. However, the negotiated rate of the two interfaces is not the maximum supported rate. For example, two GE electrical interfaces negotiate to a rate of 100 Mbit/s or 10 Mbit/s.

  • Local and remote devices connect to each other through two electrical interfaces, and auto-negotiation is enabled on the two interfaces. However, the negotiated rate of the two interfaces does not comply with protocol standards. For example, when a switch 100M electrical interface connects to a 100M electrical interface of a remote device, and auto-negotiation is enabled on the two electrical interfaces, the negotiated rates of the two interfaces are 10 Mbit/s and 100 Mbit/s respectively.

Possible Causes

  • The cable is not properly connected to the interface.
  • The network interface connector is damaged.
  • The configuration of the remote device affects rate negotiation.

Troubleshooting Procedure

c48d8beb4c7b4fdc9b5ae05191af9ca6 NOTE:

Electrical interfaces of Huawei devices must use Huawei-certified cables. Non-Huawei-certified cables may cause link faults.

Half-duplex mode may cause many problems. If the interface works in half-duplex mode, analyze the cause and make it work in full-duplex mode.

Saving the results of each troubleshooting step is recommended. If your troubleshooting fails to correct the fault, you will have a record of your actions to provide technical support personnel.

  1. Check whether the cable is correctly connected to the Ethernet electrical interface.

    Run the virtual-cable-test command in the interface view to test the cable of the Ethernet electrical interface.

    If the cable status is not OK, replace the cable.

    If the fault persists, go to step 2.

  2. Check the configurations of the local and remote devices.

    Check whether the configurations of the two devices affect rate negotiation. If so, modify or delete such configurations. For example, the rate configured using the auto speed command on the local device is too low, causing the interfaces on both ends negotiate to a rate that is smaller than the maximum supported rate.

    If the fault persists, go to step 3.

  3. Configure the two interfaces to perform rate negotiation again.

    If the fault still cannot be located and further operation can be performed, run the shutdownand undo shutdown commands in the interface view to restart one interface or remove and install the cable of the interface to enable the two interfaces to perform rate negotiation again.

    If the fault persists, go to step 4.

  4. Check the network interface connector.

    Check whether the network interface connector is damaged. For example, pins in the connector are bent, cannot rebound, or rust. If so, contact technical support personnel.

    If the fault persists, go to step 5.

  5. Collect the following information and contact technical support personnel:
    • Results of the preceding troubleshooting procedure
    • Configuration file, logs, and alarms of the device

8.4  An Ethernet Electrical Interface Discards Packets or Receives Error Packets

Fault Description

An Ethernet electrical interface discards packets or receives error packets.

Possible Causes

  • The cable is not properly connected to the interface.
  • The local and remote interfaces have different auto-negotiation modes, rates, or duplex modes.

Troubleshooting Procedure

c48d8beb4c7b4fdc9b5ae05191af9ca6 NOTE:

Electrical interfaces of Huawei devices must use Huawei-certified cables. Non-Huawei-certified cables may cause link faults.

Half-duplex mode may cause many problems. If the interface works in half-duplex mode, analyze the cause and make it work in full-duplex mode.

Saving the results of each troubleshooting step is recommended. If your troubleshooting fails to correct the fault, you will have a record of your actions to provide technical support personnel.

  1. Check whether the cable is properly connected to the interface.

    Check the cable connection.
    • Check whether the cable is loose or damaged.
    • Check whether any wires in the cable are damaged.
    Ensure that the interface can work properly.
    • Check whether the metal reed of the interface is bent or deviates.
    • Run the loopback internal command in the interface view to configure loopback detection on the interface.

    If the fault persists, go to step 2.

  2. Check whether the two interfaces have the same duplex mode, rate, and negotiation mode.

    Run the display interface command on the two interfaces to check the rates, duplex modes, and negotiation modes of the interfaces.

    Check Item

    Description

    Follow-up Procedure

    NegotiationAuto-negotiation mode of the interface:
    • ENABLE: indicates that the interface works in auto-negotiation mode.
    • DISABLE: indicates that the interface works in non-auto negotiation mode.

    The two interfaces must work in the same negotiation mode. Run the negotiation auto command in the interface view to enable auto negotiation on the interfaces. If the fault persists, disable auto negotiation and forcibly set the same rate and duplex mode on the interfaces.

    Speed

    Current rate of the interface.

    If the rates of the interfaces are different in non-auto negotiation mode, run the speed command in the interface view to set the same rate on the two interfaces.

    Duplex

    Duplex mode of the interface.

    If the duplex modes of the interfaces are different in non-auto negotiation mode, run the duplex command in the interface view to set the same duplex mode on the two interfaces.

    Mdi
    Network cable type supported by the interface:
    • across: indicates that the interface can use a crossover cable.
    • auto: indicates that the interface automatically identifies the network cable type. That is, the interface can connect to a straight-through cable or a crossover cable.
    • normal: indicates that the interface can use a straight-through cable.

    The two interfaces must support the same network cable type. By default, an interface works in auto mode. If the interfaces do not work in this mode, run the mdi command in the interface view to change the mode to auto on the interfaces.

    If the fault persists, go to step 3.

  3. Collect the following information and contact technical support personnel:
    • Results of the preceding troubleshooting procedure
    • Configuration file, logs, and alarms of the device

8.5  An Ethernet Optical Interface Discards Packets or Receives Error Packets

Fault Description

An Ethernet optical interface discards packets or receives error packets.

Possible Causes

  • The fiber is not properly connected to the interface.
  • The local and remote interfaces have different auto-negotiation modes, or duplex modes.
  • The fiber connected to the interface is too long or the fiber attenuation is high.
  • The type, transmit optical power, and wavelength of the local and remote optical modules are different.

Troubleshooting Procedure

c48d8beb4c7b4fdc9b5ae05191af9ca6 NOTE:

Optical interfaces must use Huawei-certified optical modules.

Saving the results of each troubleshooting step is recommended. If your troubleshooting fails to correct the fault, you will have a record of your actions to provide technical support personnel.

  1. Check whether the fiber is properly connected to the interface.

    Check whether the fiber or optical module is loose and whether the fiber connector is damaged or dirty. If so, replace the fiber.

    If the fault persists, go to step 2.

  2. Check whether the two interfaces have the same duplex mode, rate, and negotiation mode.

    Run the display interface command on the two interfaces to check the rates, duplex modes, and negotiation modes of the interfaces.

    Check Item

    Description

    Follow-up Procedure

    NegotiationAuto-negotiation mode of the interface:
    • ENABLE: indicates that the interface works in auto-negotiation mode.
    • DISABLE: indicates that the interface works in non-auto negotiation mode.

    The two interfaces must work in the same negotiation mode. Run the negotiation auto command in the interface view to enable auto negotiation on the interfaces. If the fault persists, disable auto negotiation and forcibly set the same rate and duplex mode on the interfaces.

    Speed

    Current rate of the interface.

    If the rates of the interfaces are different in non-auto negotiation mode, run the speed command in the interface view to set the same rate on the two interfaces.

    Duplex

    Duplex mode of the interface.

    If the duplex modes of the interfaces are different in non-auto negotiation mode, run the duplex command in the interface view to set the same duplex mode on the two interfaces.

    Mdi
    Network cable type supported by the interface:
    • across: indicates that the interface can use a crossover cable.
    • auto: indicates that the interface automatically identifies the network cable type. That is, the interface can connect to a straight-through cable or a crossover cable.
    • normal: indicates that the interface can use a straight-through cable.

    The two interfaces must support the same network cable type. By default, an interface works in auto mode. If the interfaces do not work in this mode, run the mdi command in the interface view to change the mode to auto on the interfaces.

    If the fault persists, go to step 3.

  3. Check whether the local and remote optical modules have the same wavelength.

    Run the display transceiver [ interface interface-type interface-number | slot slot-id ] [ verbose] command to check optical module information on the interface. The Wavelength(nm) field in the command output indicates the wavelength of an optical module. If the two optical modules have different wavelengths, replace one optical module to ensure that the two optical modules have the same wavelength.

    If the fault persists, go to step 4.

  4. Check the link connection.

    Remove and install the fiber and optical module to ensure that the fiber and optical module are properly connected. Check whether the fiber connector is damaged or dirty. If so, replace the fiber.

    If the fault persists, go to step 5.

  5. Check the fiber length.

    The fiber length must be shorter than the maximum transmission distance of an optical module. For the maximum transmission distance supported by different optical modules, see Optical Module in the hardware description. If the fiber length exceeds the maximum transmission distance of the optical modules, shorten the fiber length or use optical modules with a longer transmission distance.

    If the fault persists, go to step 6.

  6. Check the transmit optical power on the remote device.

    Ensure that the transmit optical power on the remote device exceeds the lower threshold.

    If the fault persists, go to step 7.

  7. Check whether the fiber type matches the optical module.

    Determine whether the fiber type matches the optical module type according to the following information:
    • A multimode fiber can be used together with multimode fiber.
    • A single-mode fiber can only be used with a single-mode optical module. A single-mode fiber is generally yellow, and a multimode fiber is generally orange.
    • Two connected optical modules must have the same wavelength.
    If the fault persists, go to step 8.
  8. Check the optical module type and vendor.

    Check whether the local and remote devices use optical modules of the same type but from different vendors. If the connected optical modules have the same wavelength and provide short-distance transmission but alarms indicating low or high optical power occur, the two optical modules may be from different vendors. Although these optical modules have the same wavelength, optical power alarms occur because different vendors design different optical power indicators for these optical modules. To rectify the fault, use optical modules of the same vendor.

    If the fault persists, go to step 9.

  9. Replace the parts.

    Using a short fiber loopback test. If the fault cannot be located, replace the optical module or fiber.

    If the fault persists, go to step 10.

  10. Collect the following information and contact technical support personnel:
    • Results of the preceding troubleshooting procedure
    • Configuration file, logs, and alarms of the device

8.6  Optical Power Alarms Occur When Two Optical Interfaces Connect to Each Other

Fault Description

Optical power alarms occur when two optical interfaces connect to each other.

Optical Power Alarms

BASETRAP_1.3.6.1.4.1.2011.5.25.129.2.17.1 hwOpticalPowerAbnormal     //An alarm indicating abnormal transmit or receive power of an optical module.
BASETRAP/3/OPTPWRABNORMAL: OID [oid] Optical module power is abnormal. (EntityPhysicalIndex=[INTEGER], BaseTrapSeverity=[INTEGER],
 BaseTrapProbableCause=[INTEGER], BaseTrapEventType=[INTEGER], EntPhysicalContainedIn=[INTEGER], EntPhysicalName="[OCTET]", Relati
veResource="[OCTET]", ReasonDescription="[OCTET]")
ENTITYTRAP_1.3.6.1.4.1.2011.5.25.219.2.4.5 hwOpticalInvalid 136193   //An alarm indicating a high transmit power of an optical module.
ENTITYTRAP_1.3.6.1.4.1.2011.5.25.219.2.4.5 hwOpticalInvalid 136194   //An alarm indicating a low transmit power of an optical module.
ENTITYTRAP_1.3.6.1.4.1.2011.5.25.219.2.4.5 hwOpticalInvalid 136195   //An alarm indicating a high receive power of an optical module.
ENTITYTRAP_1.3.6.1.4.1.2011.5.25.219.2.4.5 hwOpticalInvalid 136196   //An alarm indicating a low receive power of an optical module.
ENTITYTRAP/3/OPTICALINVALID:OID [oid] Optical Module is invalid.(Index=[INTEGER], EntityPhysicalIndex=[INTEGER], PhysicalName=\"
[OCTET]\", EntityTrapFaultID=[INTEGER])

Possible Causes

  • The local and remote optical modules have different types and wavelengths.
  • The optical module is incorrectly installed or the optical fiber fails.
  • The fiber connected to the interface is too long or the fiber attenuation is high.
  • The remote transmit power is not within the allowed range.
  • The optical module fails.

Troubleshooting Procedure

c48d8beb4c7b4fdc9b5ae05191af9ca6 NOTE:

Saving the results of each troubleshooting step is recommended. If your troubleshooting fails to correct the fault, you will have a record of your actions to provide technical support personnel.

  1. Check whether the local and remote optical modules have the same wavelength.

    Run the display transceiver [ interface interface-type interface-number | slot slot-id ] [ verbose] command to check optical module information on the interface. The Wavelength(nm) field in the command output indicates the wavelength of an optical module. If the two optical modules have different wavelengths, replace one optical module to ensure that the two optical modules have the same wavelength.

    If the fault persists, go to step 2.

  2. Check the link connection.

    Remove and install the fiber and optical module to ensure that the fiber and optical module are properly connected. Check whether the fiber connector is damaged or dirty. If so, replace the fiber.

    If the fault persists, go to step 3.

  3. Check the fiber length.

    The fiber length must be shorter than the maximum transmission distance of an optical module. For the maximum transmission distance supported by different optical modules, see Optical Module in the hardware description. If the fiber length exceeds the maximum transmission distance of the optical modules, shorten the fiber length or use optical modules with a longer transmission distance.

    If the fault persists, go to step 4.

  4. Check the transmit optical power on the remote device.

    Ensure that the transmit optical power on the remote device exceeds the lower threshold.

    If the fault persists, go to step 5.

  5. Check whether the fiber type matches the optical module.

    Determine whether the fiber type matches the optical module type according to the following information:
    • A multimode fiber can be used together with multimode fiber.
    • A single-mode fiber can only be used with a single-mode optical module. A single-mode fiber is generally yellow, and a multimode fiber is generally orange.
    • Two connected optical modules must have the same wavelength.
    If the fault persists, go to step 6.
  6. Check the optical module type and vendor.

    Check whether the local and remote devices use optical modules of the same type but from different vendors. If the connected optical modules have the same wavelength and provide short-distance transmission but alarms indicating low or high optical power occur, the two optical modules may be from different vendors. Although these optical modules have the same wavelength, optical power alarms occur because different vendors design different optical power indicators for these optical modules. To rectify the fault, use optical modules of the same vendor.

    If the fault persists, go to step 7.

  7. Replace the parts.

    Using a short fiber loopback test. If the fault cannot be located, replace the optical module or fiber.

    If the fault persists, go to step 8.

  8. Collect the following information and contact technical support personnel:
    • Results of the preceding troubleshooting procedure
    • Configuration file, logs, and alarms of the device
From group: Switch
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Created Sep 26, 2017 11:33:41 Helpful(0) Helpful(0)

S1720&S2700&S3700&S5700&S6700 Series Switches Product Troubleshooting - Preliminary-8 Interface Faults
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