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ME60 V800R010C10SPC500 Configuration Guide - IP Routing 01

This is ME60 V800R010C10SPC500 Configuration Guide - IP Routing
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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).
Configuring OSPF Multi-Area Adjacency

Configuring OSPF Multi-Area Adjacency

OSPF multi-area adjacency allows one link to be shared by multiple OSPF areas.

Usage Scenario

In OSPF, intra-area links take precedence over inter-area links. Therefore, even if a high-speed link exists between two areas, a low-speed intra-network link rather than the high-speed link is used to transmit inter-area traffic. To address this problem, run the ospf enable multi-area command to enable OSPF on a multi-area adjacency interface so that a link can be shared by multiple areas.

Among the OSPF features supported by an OSPF multi-area adjacency interface, some can be inherited from the main interface, whereas others need to be configured independently. For details, see Table 5-4.

Table 5-4 OSPF features supported by OSPF multi-area adjacency interfaces

OSPF Feature

Description

Related Configuration Links

BFD for OSPF

BFD for OSPF can be inherited from main interfaces, except for the configuration that disables BFD from an interface. This configuration needs to be configured independently for OSPF multi-area adjacency interfaces.

Disabling an OSPF Multi-Area Adjacency Interface from Creating BFD Sessions

OSPF fast convergence

OSPF multi-area adjacency interfaces support OSPF fast convergence which needs to be configured independently for these interfaces and cannot be inherited from their main interfaces.

Configuring Fast Convergence for a Multi-Area Adjacency Interface

IGP-LDP synchronization

OSPF multi-area adjacency interfaces support IGP-LDP synchronization which needs to be configured independently for these interfaces and cannot be inherited from their main interfaces.

Configuring LDP-IGP Synchronization

OSPF IP FRR

OSPF multi-area adjacency interfaces support OSPF IP FRR. OSPF IP FRR can be inherited from main interfaces, except for the configuration that disables FRR from a specified OSPF interface. This configuration needs to be configured independently for OSPF multi-area adjacency interfaces.

Disabling OSPF IP FRR on an OSPF Multi-Area Adjacency Interface

OSPF neighbor relationship flapping suppression

OSPF multi-area adjacency interfaces support OSPF neighbor relationship flapping suppression which needs to be configured independently for these interfaces and cannot be inherited from their main interfaces.

Configuring Neighbor Relationship Flapping Suppression on an OSPF Multi-Area Adjacency Interface

OSPF flush LSA source tracing

OSPF multi-area adjacency interfaces support OSPF flush LSA source tracing which can be inherited from their main interfaces.

Configuring OSPF Flush LSA Source Tracing

OSPF TE

OSPF multi-area adjacency interfaces inherit TE information from their main interfaces.

Configuring IGP TE (OSPF or IS-IS)

Pre-configuration Tasks

Before configuring OSPF multi-area adjacency, complete the following tasks:

  • Configure a link layer protocol.

  • Assign an IP address to each interface to ensure reachability between neighboring nodes at the network layer.

  • Configure basic OSPF functions.

Configuration Procedures

Figure 5-9 Flowchart for configuring OSPF multi-area adjacency

Enabling OSPF on a Multi-Area Adjacency Interface

Enabling OSPF on a multi-area adjacency interface is the prerequisite for configuring basic multi-area adjacency functions.

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run ospf [ process-id | router-id router-id ] *

    An OSPF process is started, and the OSPF view is displayed.

  3. Run area area-id

    The OSPF area view is displayed.

  4. Enable OSPF on an interface.
    1. Run twice quit

      The system view is displayed.

    2. Run interface interface-type interface-number

      The interface view is displayed.

    3. Run ospf enable [ process-id ] area area-id

      OSPF is enabled on the interface.

  5. Run ospf enable multi-area area-id

    OSPF is enabled on the multi-area adjacency interface.

  6. (Optional) Run ospf mtu-enable multi-area area-id

    The multi-area adjacency interface is configured to add its MTU to the DD packets to be sent and check whether the MTU in each received DD packet exceeds the local interface MTU.

    The default MTU may vary with the device manufacturer. To keep consistency, prevent the interface from adding its MTU to the DD packets to be sent.

    If the MTU in DD packets is changed, neighbor relationships will be reestablished.

  7. Run commit

    The configuration is committed.

Configuring a Cost for a Multi-Area Adjacency Interface

Configuring a cost for a multi-area adjacency interface can control route selection.

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run interface interface-type interface-number

    The interface view is displayed.

  3. Run ospf enable [ process-id ] area area-id

    OSPF is enabled on the interface.

  4. Run ospf enable multi-area area-id

    OSPF is enabled on the multi-area adjacency interface.

  5. Run ospf cost cost multi-area area-id

    A cost is configured for the multi-area adjacency interface.

  6. Run commit

    The configuration is committed.

Configuring an Authentication Mode for a Multi-Area Adjacency Interface

Configuring an authentication mode for a multi-area adjacency interface improves OSPF network security.

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run interface interface-type interface-number

    The interface view is displayed.

  3. Run ospf enable [ process-id ] area area-id

    OSPF is enabled on the interface.

  4. Run ospf enable multi-area area-id

    OSPF is enabled on the multi-area adjacency interface.

  5. Run either of the following commands:

    • Run the ospf authentication-mode simple [ plain plain-text | [ cipher ] cipher-text ] multi-area area-id command to configure simple authentication for the multi-area adjacency interface.

    • Run the ospf authentication-mode { md5 | hmac-md5 | hmac-sha256 } [ key-id { plain plain-text | [ cipher ] cipher-text } ] multi-area area-id command to configure ciphertext authentication for the multi-area adjacency interface.

    • Run the ospf authentication-mode keychain keychain-name multi-area area-id command to configure keychain authentication for the multi-area adjacency interface.

    • Run the ospf authentication-mode null multi-area area-id command to configure null authentication for the multi-area adjacency interface.

  6. Run commit

    The configuration is committed.

Configuring Fast Convergence for a Multi-Area Adjacency Interface

Configuring fast convergence for a multi-area adjacency interface improves network performance.

Procedure

  • Configure the interval at which a multi-area adjacency interface sends Hello packets.
    1. Run system-view

      The system view is displayed.

    2. Run interface interface-type interface-number

      The interface view is displayed.

    3. Run ospf enable [ process-id ] area area-id

      OSPF is enabled on the interface.

    4. Run ospf enable multi-area area-id

      OSPF is enabled on the multi-area adjacency interface.

    5. Run ospf timer hello interval multi-area area-id

      The interval at which Hello packets are sent is configured on the multi-area adjacency interface.

    6. Run commit

      The configuration is committed.

  • Configure the dead interval of OSPF neighbor relationships for a multi-area adjacency interface.
    1. Run system-view

      The system view is displayed.

    2. Run interface interface-type interface-number

      The interface view is displayed.

    3. Run ospf enable [ process-id ] area area-id

      OSPF is enabled on the interface.

    4. Run ospf enable multi-area area-id

      OSPF is enabled on the multi-area adjacency interface.

    5. Run ospf timer dead interval multi-area area-id

      The dead interval of OSPF neighbor relationships is configured for the multi-area adjacency interface.

    6. Run commit

      The configuration is committed.

  • Configure an LSA retransmission interval on a multi-area adjacency interface.
    1. Run system-view

      The system view is displayed.

    2. Run interface interface-type interface-number

      The interface view is displayed.

    3. Run ospf enable [ process-id ] area area-id

      OSPF is enabled on the interface.

    4. Run ospf enable multi-area area-id

      OSPF is enabled on the multi-area adjacency interface.

    5. Run ospf timer retransmit interval multi-area area-id

      An LSA retransmission interval is configured on the multi-area adjacency interface.

    6. Run commit

      The configuration is committed.

  • Configure an LSA transmission delay on a multi-area adjacency interface.
    1. Run system-view

      The system view is displayed.

    2. Run interface interface-type interface-number

      The interface view is displayed.

    3. Run ospf enable [ process-id ] area area-id

      OSPF is enabled on the interface.

    4. Run ospf enable multi-area area-id

      OSPF is enabled on the multi-area adjacency interface.

    5. Run ospf trans-delay interval multi-area area-id

      An LSA transmission delay is configured on the multi-area adjacency interface.

    6. Run commit

      The configuration is committed.

  • Configure smart-discover on a multi-area adjacency interface.
    1. Run system-view

      The system view is displayed.

    2. Run interface interface-type interface-number

      The interface view is displayed.

    3. Run ospf enable [ process-id ] area area-id

      OSPF is enabled on the interface.

    4. Run ospf enable multi-area area-id

      OSPF is enabled on the multi-area adjacency interface.

    5. Run ospf smart-discover multi-area area-id

      Smart-discover is enabled on the multi-area adjacency interface.

      Without smart-discover, if the neighbor status of a device on a P2P network changes or the DR or BDR on a multi-access network (broadcast or NBMA network) changes, Hello packets are not sent to neighbors until the Hello timer expires. This slows down the establishment of neighbor relationships. With smart-discover, Hello packets are sent to neighbors immediately in this case, regardless of the Hello timer. This speeds up neighbor relationship establishment and network convergence.

    6. Run commit

      The configuration is committed.

  • Configure a multi-area adjacency interface to filter the LSAs to be sent.
    1. Run system-view

      The system view is displayed.

    2. Run interface interface-type interface-number

      The interface view is displayed.

    3. Run ospf enable [ process-id ] area area-id

      OSPF is enabled on the interface.

    4. Run ospf enable multi-area area-id

      OSPF is enabled on the multi-area adjacency interface.

    5. Run ospf filter-lsa-out { all | { summary [ acl { acl-number | acl-name } ] | ase [ acl { acl-number | acl-name } ] | nssa [ acl { acl-number | acl-name } ] } * } multi-area area-id

      The multi-area adjacency interface is configured to filter the LSAs to be sent.

      If multiple links exist between two devices, you can configure the local device to filter the LSAs to be sent. This prevents unnecessary LSA transmission and reserves bandwidth resources.

    6. Run commit

      The configuration is committed.

Configuring Neighbor Relationship Flapping Suppression on an OSPF Multi-Area Adjacency Interface

Neighbor relationship flapping suppression can be configured on an OSPF multi-area adjacency interface to delay OSPF neighbor relationship reestablishment or set the link cost to the maximum value in case of neighbor relationship flapping.

Usage Scenario

If an interface carrying OSPF services alternates between Up and Down, OSPF neighbor relationship flapping occurs on the interface. During the flapping, OSPF frequently sends Hello packets to reestablish the neighbor relationship, synchronizes LSDBs, and recalculates routes. In this process, a large number of packets are exchanged, adversely affecting neighbor relationship stability, OSPF services, and other OSPF-dependent services, such as LDP and BGP. OSPF neighbor relationship flapping suppression can address this problem by delaying OSPF neighbor relationship reestablishment or preventing service traffic from passing through flapping links.

NOTE:
The following steps are optional, choose them as required.

Procedure

  1. Run system-view

    The system view is displayed.

    By default, OSPF neighbor relationship flapping suppression is enabled globally. To disable this function globally, run the suppress-flapping peer disable command.

  2. Run interface interface-type interface-number

    The interface view is displayed.

  3. Run ospf enable [ process-id ] area area-id

    OSPF is enabled on the interface.

  4. Run ospf enable multi-area area-id

    OSPF is enabled on the multi-area adjacency interface.

  5. (Optional) Run ospf suppress-flapping peer disable multi-area area-id

    OSPF neighbor relationship flapping suppression on a multi-area adjacency interface is disabled.

    By default, OSPF neighbor relationship flapping suppression is enabled on all multi-area adjacency interfaces in the same OSPF process. To disable the function from one of the interfaces, run this command.

  6. Run ospf suppress-flapping peer hold-down interval multi-area area-id

    The Hold-down mode is configured on a multi-area adjacency interface, and its duration is set.

    Flapping suppression works in either Hold-down or Hold-max-cost mode.

    • Hold-down mode: In the case of frequent flooding and topology changes during neighbor relationship establishment, interfaces prevent neighbor relationship reestablishment during Hold-down suppression, which minimizes LSDB synchronization attempts and packet exchanges.

    • Hold-max-cost mode: If the traffic forwarding path changes frequently, interfaces use 65535 (the maximum cost) as the cost of the flapping link during Hold-max-cost suppression, which prevents traffic from passing through the flapping link.

      NOTE:
      To change the cost used by the Hold-max-cost mode, run the maximum-link-cost cost command.

    Flapping suppression can also work first in Hold-down mode and then in Hold-max-cost mode.

    To disable the Hold-max-cost mode, run the ospf suppress-flapping peer hold-max-cost disable multi-area command.

  7. Run ospf suppress-flapping peer { detecting-interval detecting-interval | threshold threshold | resume-interval resume-interval } * multi-area area-id

    Detection parameters are configured for OSPF neighbor relationship flapping suppression on an OSPF multi-area adjacency interface.

    • Specifies the interval for exiting from OSPF neighbor relationship flapping suppression.

      If the interval between two successive neighbor status changes from Full to a non-Full state is longer than resume-interval, the flapping_count is reset.

    • If OSPF neighbor relationship flapping suppression works in hold-max-cost mode, resume-interval indicates the duration of this mode.
    NOTE:
    The value of resume-interval must be greater than that of detecting-interval.

    You can configure the detection parameters as required. However, keeping the default configurations is recommended. By default, the detection interval of OSPF neighbor relationship flapping suppression on multi-area adjacency interfaces is 60s, the suppression threshold is 10, and the interval for exiting from suppression is 120s.

  8. Run quit

    The system view is displayed.

  9. Run quit

    The user view is displayed.

  10. Run reset ospf suppress-flapping process-id peer [ interface-name [ all-areas | area area-id ] ] | [ interface-type interface-number [ all-areas | area area-id ] ] [ notify-peer ]

    The OSPF process or the multi-area adjacency interface is configured to exit from OSPF neighbor relationship flapping suppression.

    NOTE:

    The OSPF process or interface exits from flapping suppression in the following scenarios:

    • The suppression timer expires.
    • The corresponding OSPF process is reset.
    • An OSPF neighbor is reset using the reset ospf peer command.
    • OSPF neighbor relationship flapping suppression is disabled globally using the suppress-flapping peer disable (OSPF) command.
    • The reset ospf suppress-flapping peer command is run.

  11. Run commit

    The configuration is committed.

Disabling an OSPF Multi-Area Adjacency Interface from Creating BFD Sessions

After BFD for OSPF is configured, all interfaces on which neighbor relationships are in Full state in the OSPF process create BFD sessions. You can disable an interface from creating BFD sessions as required.

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run interface interface-type interface-number

    The interface view is displayed.

  3. Run ospf enable [ process-id ] area area-id

    OSPF is enabled on the interface.

  4. Run ospf enable multi-area area-id

    OSPF is enabled on the multi-area adjacency interface.

  5. Run ospf bfd block multi-area area-id

    The OSPF multi-area adjacency interface is disabled from creating BFD sessions.

  6. Run commit

    The configuration is committed.

Disabling OSPF IP FRR on an OSPF Multi-Area Adjacency Interface

OSPF IP fast reroute (FRR) can be disabled on an OSPF multi-area adjacency interface that is connected to a link carrying key services. This prevents FRR from calculating the link as the backup link and minimizes any potential impact on the services.

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run interface interface-type interface-number

    The interface view is displayed.

  3. Run ospf enable [ process-id ] area area-id

    OSPF is enabled on the interface.

  4. Run ospf enable multi-area area-id

    OSPF is enabled on the multi-area adjacency interface.

  5. Run ospf frr block multi-area area-id

    OSPF IP FRR is disabled on the OSPF multi-area adjacency interface.

  6. (Optional) Run ospf remote-lfa disable multi-area area-id

    Remote loop-free alternate (LFA) is disabled on the OSPF multi-area adjacency interface.

  7. Run commit

    The configuration is committed.

Configuring a Fallback Cost for an Eth-Trunk Multi-Area Adjacency Interface

Configuring a fallback cost for an Ethernet multi-area adjacency interface helps control route selection.

Context

If a member interface of an Eth-Trunk multi-area adjacency interface goes down, the remaining bandwidth of the Eth-Trunk multi-area adjacency interface may fail to meet user requirements. As a result, user services are affected. To address this problem, run the ospf cost-fallback multi-area command to configure cost-fallback parameters (fallback cost and bandwidth threshold) for the Eth-Trunk multi-area adjacency interface; if the remaining bandwidth of the interface goes below the bandwidth threshold, the cost of the interface is changed to the fallback cost which is higher than the normal cost, and traffic is then switched to an alternative path; when the remaining bandwidth of the interface reaches or exceeds the bandwidth threshold, the original cost is restored.

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run interface eth-trunk trunk-id

    The Eth-Trunk interface view is displayed.

  3. Run ospf enable [ process-id ] area area-id

    OSPF is enabled on the interface.

  4. Run ospf enable multi-area area-id

    OSPF is enabled on the multi-area adjacency interface.

  5. Run ospf cost-fallback fallbackcost threshold fallbackbw multi-area area-id

    A fallback cost is configured for an Eth-Trunk multi-area adjacency interface.

  6. Run commit

    The configuration is committed.

Maintaining OSPF on a Multi-Area Adjacency Interface

Context

OSPF statistics cannot be restored after being cleared. Therefore, exercise caution before clearing the OSPF statistics.

To clear OSPF statistics, run the following command in the user view.

Procedure

  • Run reset ospf [ process-id ] counters [ neighbor [ interface-type interface-number [ all-areas | area area-id ] ] | [ interface-name [ all-areas | area area-id ] ] [ router-id ] ]

    OSPF statistics are cleared.

Verifying the Configuration of OSPF Multi-Area Adjacency

After configuring OSPF multi-area adjacency, verify the configuration.

Prerequisites

OSPF multi-area adjacency has been configured.

Procedure

  • Run the following commands and check (M) Indicates MADJ interface, Multi-area interface, and Multi-area Interface Count fields to view configurations on the multi-area adjacency interface:

    • display ospf brief
    • display ospf interface
    • display ospf peer

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Updated: 2019-01-04

Document ID: EDOC1100059437

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