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ME60 Troubleshooting Guide V1.0 (VRPv8)

This document provides the maintenance guide of the device, including daily maintenance, emergence maintenance, and typical troubleshooting.
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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
IS-IS Troubleshooting

IS-IS Troubleshooting

This chapter describes common IS-IS faults and provides troubleshooting procedures with troubleshooting cases.

For details about IS-IS, refer to HUAWEI ME60 Feature Description - IS-IS.

The IS-IS Neighbor Relationship Cannot Be Established

This section describes how to troubleshoot the IS-IS neighbor relationship establishment failure.

Common Causes

Common causes are as follows:

  • Hello packets cannot be sent or received by IS-IS due to a device or link fault.
  • The same system ID is configured for devices at both ends of the link.
  • The MTUs configured on the interfaces at both ends of the link are different or the MTU of an interface is smaller than the length of a Hello packet to be sent.
  • The IP addresses at both ends of the link are on different network segments.
  • The authentication configurations on the IS-IS interfaces at both ends of the link are inconsistent.
  • The IS-IS levels at both ends of the link are inconsistent.
  • The area addresses of the devices at both ends of the link are inconsistent when the devices establish the IS-IS Level-1 neighbor relationship.
Troubleshooting Flowchart

Figure 4-62 shows the troubleshooting flowchart.

Figure 4-62 Flowchart for troubleshooting the IS-IS neighbor relationship establishment failure

Troubleshooting Procedure

Context

NOTE:

After the commands are configured to troubleshoot the faults, check the configuration validation mode to ensure that the configurations take effect. Unless otherwise specified, this manual defaults to immediate validation mode.

  • In immediate validation mode, the configurations take effect after the commands are entered.
  • In two-phase validation mode, after the commands are configured, the commit command needs to be run to commit the configurations.

Save the results of each troubleshooting step so that if your troubleshooting attempts fail to correct the fault, you will have a record of your actions to present to Huawei.

Procedure

  1. Check the status of the IS-IS interfaces.

    Run the display isis interface command to check the value of IPv4.State or IPv6.State (status of the IS-IS interfaces).

    • If the value is Mtu:Up/Lnk:Dn/IP:Dn, go to Step 2.

    • If the value is Mtu:Dn/Lnk:Up/IP:Up, run the display current-configuration interface interface-type [ interface-number ] command to check the MTUs on the interfaces. Run the display current-configuration configuration isis command to check the lengths of LSPs in an IS-IS process.
      NOTE:

      If the lengths of LSPs are not displayed in the display current-configuration configuration isis command output, the default LSP lengths are used. To check the default LSP lengths, run the display default-parameter isis command. The value of the LSP-Originate-Length field is the maximum length of an originated LSP, and the value of the LSP-Receive-Length field is the maximum length of a received LSP.

      If the MTU is not displayed in the display current-configuration interface interface-type [ interface-number ] command output, the default MTU is used. The default MTU is 1500 bytes on the other interfaces.

      On a P2P interface, the LSP length must not be greater than the MTU on the P2P interface. On a broadcast interface, the value (MTU – LSP length) must be greater than or equal to 3; otherwise, run the lsp-length command in the IS-IS view to change the LSP length, or run the mtu command in the interface view to change the MTU.

      If two Huawei devices need to communicate with each other, check whether the MTUs on the connected interfaces are the same. If a Huawei device needs to communicate with a non-Huawei device, adjust the MTUs on both ends as required.

      If the fault persists, go to Step 4.

    • If the value is Down, run the display current-configuration configuration isis command to check the configuration of the IS-IS process. Check whether the NET is configured in the IS-IS process. If not, configure the network-entity command in the IS-IS process.

      If the fault persists, go to Step 2.

    • If the value is Up, go to Step 4.

  2. Check that the interface is Up.

    Run the display ip interface [ interface-type [ interface-number ] ] command to check the status of specified interfaces.

    • If the value of Line protocol current state in the command output is not Up, troubleshoot the interface fault. For details, see the section "Physical Connection and Interfaces" or "L2 Network".

      If the fault persists, go to Step 3.

    • If the interface is Up, go to Step 3.

  3. Check that the IP addresses at both ends are on the same network segment.
    • If the IP addresses are on different network segments, change the IP addresses to ensure that they are on the same network segment. If the fault persists, go to Step 4.

    • If the IP addresses are on the same network segment, go to Step 4.

  4. Check that the device can receive Hello packets.

    Run the display isis statistics packet [ interface interface-type interface-number ] command to check whether the device has received Hello packets.
    NOTE:

    Run this command at the Hello packet sending interval (10s by default) or a greater interval to check whether the packet statistics (L1 IIH or L2 IIH) increase.

    On a broadcast interface, Hello packets have IS-IS levels. Therefore, you can view the statistics about the Hello packets based on the levels of established neighbor relationships. On a P2P interface, the Hello packets have no IS-IS levels and are recorded as L2 IIH packets.

    • If the device cannot receive Hello packets, go to Step 10.

    • If the device can receive Hello packets, go to Step 5.

  5. Check the statistics about error Hello packets received.

    Run the display isis error interface interface-type interface-number command at the Hello packet sending interval (10s by default) or a greater interval to check the statistics about error Hello packets received.

    Perform one of the following operations based on the command output:
    • If the value of Repeated System ID increases with time, go to Step 6.
    • If the value of Mismatched Level increases with time, go to Step 7.
    • If the value of Bad Area Addr TLV, No Area Addr TLV, or Longer Area Addr increases with time, go to Step 8.
    • If the value of Bad Authentication increases with time, go to Step 9.
    • If the values of any other fields (different from any of the preceding ones) increase with time, go to Step 10.

  6. Check that the devices at both ends are configured with different system IDs.

    Run the display current-configuration configuration isis command to check whether the system IDs are the same.

    • If the system IDs are the same, set different system IDs.

    • If the system IDs are different, go to Step 6.

  7. Check that the IS-IS levels at both ends match.

    Run the display current-configuration configuration isis | include is-level command to check the levels of the IS-IS processes on the two devices. Then, run the display current-configuration interface interface-type interface-number | include isis circuit-level command to check whether the IS-IS levels at both ends match. The IS-IS neighbor relationship can be established only when the IS-IS levels match.

    NOTE:

    If the IS-IS levels of the two interfaces are not displayed in the display current-configuration interface interface-type interface-number | include isis circuit-level command output, the two interfaces use the default IS-IS level. To check the default IS-IS level, run the display default-parameter isis command. The value of the Circuit-Level field is the default IS-IS level.

    The interface levels match as follows:
    • If the level of the local interface is Level-1, the level of the remote interface must be Level-1 or Level-1-2.

    • If the level of the local interface is Level-2, the level of the remote interface must be Level-2 or Level-1-2.

    • If the level of the local interface is Level-1-2, the level of the remote interface can be Level-1, Level-2, or Level-1-2.

    • If the IS-IS levels of the two devices do not match, run the is-level command in the IS-IS view to adjust the IS-IS level, or run the isis circuit-level command in the interface view to change the interface level.

    • If the IS-IS levels match, go to Step 7.

  8. Check that the area addresses at both ends are the same.
    • If the area addresses are different, run the network-entity command in the IS-IS view to set the same area address.

    • If the area addresses are the same, go to Step 8.

    NOTE:

    If you want to establish a Level-1 neighbor relationship between two devices, ensure that the two devices are in the same area. When a Level-2 neighbor relationship is to be established between two devices, the area addresses do not need to match.

  9. Check that the authentication configurations at both ends are the same.

    Run the display current-configuration interface interface-type interface-number | include isis authentication-mode command to check whether the IS-IS authentication configurations of the two interfaces at both ends are the same.

    • If the authentication types are different, run the isis authentication-mode command in the view of each of the two interfaces to set the same authentication type.

    • If the authentication passwords are different, run the isis authentication-mode command in the view of each of the two interfaces to set the same authentication password.

    • If the authentication configurations are the same, go to Step 9.

  10. Please contact technical support personnel and provide the following information:

    • Results of this troubleshooting procedure
    • Configuration, log, and alarm files

Relevant Alarms and Logs

Relevant Alarms

None

Relevant Logs

None

A Device Fails to Learn Specified IS-IS Routes from Its Neighbor

This section describes how to troubleshoot the failure of a device in learning specified IS-IS routes from its neighbor.

Common Causes

Common causes are as follows:

  • The same routes are advertised by another routing protocol with a higher priority than IS-IS.
  • The imported external route is not selected because its priority is not high enough.
  • The IS-IS cost styles are inconsistent.
  • The IS-IS neighbor relationship has not been established between the two devices.
  • The same system ID is configured for the two devices.
  • The authentication configurations at both ends are inconsistent.
  • LSPs are discarded due to a device or link fault.
Troubleshooting Flowchart

The troubleshooting roadmap is as follows:
  • Check that another protocol also advertises the specified routes.
  • Check that IS-IS calculates routes.
  • Check that IS-IS LSDBs are synchronized.
  • Check that the IS-IS configuration is correct.

Figure 4-63 shows the troubleshooting flowchart.

Figure 4-63 Flowchart for troubleshooting the failure of a device in learning specified IS-IS routes from its neighbor

Troubleshooting Procedure

Context

NOTE:

After the commands are configured to troubleshoot the faults, check the configuration validation mode to ensure that the configurations take effect. Unless otherwise specified, this manual defaults to immediate validation mode.

  • In immediate validation mode, the configurations take effect after the commands are entered.
  • In two-phase validation mode, after the commands are configured, the commit command needs to be run to commit the configurations.

Save the results of each troubleshooting step so that if your troubleshooting attempts fail to correct the fault, you will have a record of your actions to present to Huawei.

Procedure

  1. Check that the specified routes exist in the IS-IS routing table.

    Run the display isis route command to view the IS-IS routing table.

    • If the specified routes exist in the IS-IS routing table, run the display ip routing-table ip-address [ mask | mask-length ] verbose command to check whether routes advertised by another routing protocol with a higher priority than IS-IS exist in the IP routing table.
      NOTE:

      If the value of the State field of a route is Active Adv, the route is active. If there are multiple routes that have the same prefix but are advertised by different routing protocols, the route advertised by the routing protocol with the highest priority is active.

      • If such routes exist in the routing table, adjust the configuration based on the network planning.

      • If no such routes exist in the routing table, go to Step 6.

    • If the specified routes do not exist in the IS-IS routing table, go to Step 2.

  2. Check that the specified IS-IS routes are advertised.

    On the device that advertises the specified routes, run the display isis lsdb verbose local command to check whether the specified routes are carried in locally generated LSPs.

    • If the specified routes are not carried in locally generated LSPs, check whether the configurations of the device are correct, for example, whether IS-IS is enabled on the corresponding interface.
      NOTE:

      If the specified routes are imported external routes, run the display ip routing-table protocol protocol verbose command to check whether the external routes are active.

    • If the specified routes are carried in locally generated LSPs, go to Step 3.

  3. Check that IS-IS LSDBs are synchronized.

    On the device that fails to learn the specified IS-IS routes, run the display isis lsdb command to check whether the device has learned LSPs from the device that advertises the specified routes.
    NOTE:

    LSPID identifies an LSP, and Seq Num is the sequence number of an LSP. The greater the sequence number, the newer the LSP.

    • If the LSDB of the device that fails to learn the specified IS-IS routes does not have specified LSPs, check whether a lower-layer or link failure occurs.

    • If the LSDB has specified LSPs, but the Seq Num fields of the LSPs are different from those in the display isis lsdb local verbose command output and the values of the Seq Num fields keep increasing, another device with the same system ID as the device advertises the specified routes on the network. In this case, check the IS-IS configurations on the devices on the network.

    • If the LSDB has specified LSPs, but the Seq Num fields of the LSPs are different from those in the display isis lsdb local verbose command output and the values of the Seq Num fields remain unchanged, the LSPs may be discarded during transmission. In this case, check whether a lower-layer or link failure occurs.

    • If the LSDB has specified LSPs and the Seq Num fields of the LSPs are the same as those in the display isis lsdb local verbose command output, go to Step 4.

  4. Check that the IS-IS cost styles are consistent.

    Run the display current-configuration configuration isis command on the device that advertises the specified routes and the device that fails to learn the specified IS-IS routes to check whether the IS-IS cost styles of the two devices configured using the cost-style command are consistent.

    NOTE:

    Two devices can learn routes from each other only when the IS-IS cost styles match.

    The IS-IS cost styles are classified as follows:
    • Narrow: indicates that the packets with a narrow cost style can be sent and received.

    • Narrow-compatible: indicates that the packets with a narrow or wide cost style can be received but only the packets with a narrow cost style can be sent.

    • Compatible: indicates that the packets with a narrow or wide cost style can be sent and received.

    • Wide-compatible: indicates that the packets with a narrow or wide cost style can be received but only the packets with a wide cost style can be sent.

    • Wide: indicates that the packets with a wide cost style can be sent and received.

    If the cost style of one device is narrow and the cost style of the other device is wide or wide-compatible, or the cost style of one device is Narrow-compatible and the cost style of the other device is wide, the two devices cannot interwork.

    • If the IS-IS cost styles on the two devices are inconsistent, run the cost-style command to change the cost style of either end so that both ends have the same IS-IS cost style.

    • If the IS-IS cost styles on the two devices are consistent, go to Step 5.

  5. Check that the IS-IS neighbor relationship has been established.

    Run the display isis peer command on every device on the path to check whether the IS-IS neighbor relationship has been established.

  6. Please contact technical support personnel and provide the following information:

    • Results of this troubleshooting procedure
    • Configuration, log, and alarm files

Relevant Alarms and Logs

Relevant Alarms

None

Relevant Logs

None

IS-IS Routes Flap

This section describes how to troubleshoot IS-IS route flapping.

Common Causes

Common causes are as follows:

  • The IS-IS neighbor relationship flaps.
  • The MPLS LSP flaps.
  • The same external routes are imported to IS-IS by the two devices, but the priorities of the imported external routes are lower than those of IS-IS routes.
  • The same system ID is configured for the two devices.
Troubleshooting Flowchart

The troubleshooting roadmap is as follows:
  • Check the details about route flapping to identify the changed route attributes.

Figure 4-64 shows the troubleshooting flowchart.

Figure 4-64 Flowchart for troubleshooting IS-IS route flapping

Troubleshooting Procedure

Context

NOTE:

After the commands are configured to troubleshoot the faults, check the configuration validation mode to ensure that the configurations take effect. Unless otherwise specified, this manual defaults to immediate validation mode.

  • In immediate validation mode, the configurations take effect after the commands are entered.
  • In two-phase validation mode, after the commands are configured, the commit command needs to be run to commit the configurations.

Save the results of each troubleshooting step so that if your troubleshooting attempts fail to correct the fault, you will have a record of your actions to present to Huawei.

Procedure

  1. Check the details about route flapping.

    Run the display ip routing-table ip-address verbose command to check the details about route flapping, such as, the routing protocol from which active routes are learned and the changed route attributes during route flapping.

    • If the value of the TunnelID field changes after route flapping, run the display mpls lsp command to check whether the LDP LSP is Up only for a short time. If the LDP LSP is Up only for a short time, the LDP LSP flaps. If the MPLS LSP flaps, see LDP LSP Flapping or TE Tunnel Goes Down Suddenly.

    • If the Cost or Interface field of a route changes, check whether the IS-IS neighbor relationship established between devices on the path flaps. If the IS-IS neighbor relationship flaps, see ISIS_1.3.6.1.3.37.2.0.17 isisAdjacencyChange.

    • If a route appears intermittently in the routing table (the value of the Age field changes), run the display isis lsdb verbose command to identify the LSP that carries the route. Then, run the display isis lsdb verbose lsp-id command to check the updates of the LSP.
      • If the LSP always carries the specified route, check whether the IS-IS neighbor relationship established between devices on the path flaps.

      • If the value of the Seq Num field of the LSP constantly increases and the contents of the LSP change dramatically after the update, check whether the same system ID is configured for the two devices. To check the system ID, run the display isis brief command.

      • If the value of the Seq Num field of the LSP constantly increases and the route appears intermittently before and after the LSP is updated, perform 2 on the device that generates the LSP.

    • If the value of the Protocol field of the route changes, go to 2.

  2. Check the external routes imported by IS-IS.

    If the specified routes are external routes imported by IS-IS, run the display ip routing-table ip-address verbose command on the device where IS-IS imports the external routes to view details about route flapping.

    • If the active routes in the routing table are IS-IS routes rather than the external routes to be imported by IS-IS, other IS-IS devices advertise the same routes. In this case, modify the priorities of routing protocols based on network planning, or configure a route filtering policy in the IS-IS view to control the routes to be added to the IP routing table.

    • In all other cases, go to 3.

  3. Please contact technical support personnel and provide the following information:

    • Results of this troubleshooting procedure
    • Configuration, log, and alarm files

Relevant Alarms and Logs

Relevant Alarms

None

Relevant Logs

None

The Routing Information of the IS-IS Multicast Topology Is Incorrect

This section describes how to troubleshoot incorrect routing information of the IS-IS multicast topology.

Common Causes

Common causes are as follows:

  • Multicast configurations on an IS-IS interface are incorrect, causing incorrect multicast topology status of IS-IS neighbors.
  • PIM-SM is not enabled on the interface. As a result, the route to the network segment where the interface resides is not advertised to the IS-IS multicast topology.
  • The IS-IS multicast topology is not used by multicast due to improper configurations.
Troubleshooting Flowchart

The troubleshooting roadmap is as follows:
  • Check that the IS-IS interface is added to the multicast topology.
  • Check that the multicast status of the IS-IS interface is Up.
  • Check that the multicast status of neighbors is Up.
  • Check that the routes for the IS-IS multicast topology are correct.

Figure 4-65 shows the troubleshooting flowchart.

Figure 4-65 Flowchart for troubleshooting incorrect routing information of the IS-IS multicast topology

Troubleshooting Procedure

Context

NOTE:

Save the results of each troubleshooting step. If the fault persists after following this procedure, Huawei will need these results for further troubleshooting.

Procedure

  1. Check that the IS-IS interface is added to a multicast topology.

    Run the display isis interface verbose command to check whether the IS-IS interface is added to a multicast topology.

    • If IPv4 MT 3 is not displayed in the command output, the interface is not added to the multicast topology. To add the interface to the multicast topology, run the isis topology multicast command in the interface view.
      NOTE:
      Before adding the interface to the multicast topology, perform the following configurations:
      • Run the ip topology multicast command in the system view to create a multicast topology.

      • Run the cost-style wide or cost-style wide-compatible command in the IS-IS view to change the cost style of IS-IS.

      • Run the topology multicast topology-id 3 command in the IS-IS view to configure an IPv4 IS-IS multicast topology.

      • Run the ip topology multicast enable command in the interface view to add the interface to the multicast topology.

      • Run the isis topology multicast command in the interface view to add the IS-IS interface to the IS-IS multicast topology.

    • If IPv4 MT 3 is displayed in the command output, the interface has been added to the multicast topology. Then, go to Step 2.

  2. Check that the multicast topology status of the IS-IS interface is Up.

    Run the display isis interface verbose command to check whether the multicast topology status of the IS-IS interface is Up.

    NOTE:

    If multicast is displayed in the IPv4 MT 3 field in the command output, the multicast topology status of the IS-IS interface is Up; if multicast (NO PIM) is displayed in the IPv4 MT 3 field in the command output, the multicast topology status of the IS-IS interface is not Up.

    • If the multicast topology status of the IS-IS interface is not Up, run the pim sm command in the interface view to enable PIM-SM.

    • If the multicast topology interface is Up, go to Step 3.

  3. Check that the multicast topology status of the neighbor is Up.

    Run the display isis peer verbose command to check whether the multicast topology status of the neighbor is Up.
    NOTE:

    If the displayed MT IDs supported field in the command output is 3(UP), in which 3 is the ID of the IPv4 IS-IS multicast topology, the multicast topology status of the IS-IS neighbor is Up; otherwise, the multicast topology status of the IS-IS neighbor is not Up.

    • If the multicast topology status of the IS-IS neighbor is not Up, perform Step 1 and Step 2 on the remote device to ensure that all devices and their interfaces in the multicast topology are correctly configured and that the interface that originates the source route is added to the IS-IS multicast topology. Then, run the pim sm command to enable PIM-SM.

    • If the multicast topology status of the IS-IS neighbor is Up, go to 4.

  4. Check that the routes for the IS-IS multicast topology are correct.

    Run the display isis route topology multicast command to check whether the routes for the IS-IS multicast topology are correct.

    • If the routes for the IS-IS multicast topology are correct, the fault is rectified.

    • If the routes for the IS-IS multicast topology are incorrect, go to 5.

  5. Please contact technical support personnel and provide the following information:

    • Results of this troubleshooting procedure
    • Configuration, log, and alarm files

Relevant Alarms and Logs

Relevant Alarms

None

Relevant Logs

None

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Updated: 2019-06-11

Document ID: EDOC1000175918

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