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Configuration Guide - IP Unicast Routing

CloudEngine 8800, 7800, 6800, and 5800 V200R005C10

This document describes the configurations of IP Unicast Routing, including IP Routing, Static Route, RIP, RIPng, OSPF, OSPFv3, IPv4 IS-IS, IPv6 IS-IS, BGP, Routing Policy, and PBR.
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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 Dynamic BFD for IS-IS

Configuring Dynamic BFD for IS-IS

Context

On an IS-IS network, a device periodically sends Hello packets to detect the neighbor status change. By default, the device considers a neighbor Down when it does not receive a Hello packet from the neighbor after sending three Hello packets (30 seconds). This IS-IS fault detection mechanism, however, cannot provide high reliability for the network that requires fast network convergence and no packet loss. BFD for IS-IS can solve this problem. BFD is a millisecond-level fault detection mechanism. It can detect faults on the link between IS-IS neighbors within 50 ms. Therefore, BFD can speed up IS-IS route convergence, ensures fast link switchover, and reduces traffic loss.

Dynamic BFD for IS-IS implements dynamic setup of BFD sessions. When a new IS-IS neighbor relationship is set up, BFD is notified of the neighbor parameters and the detection parameters (including source and destination IP addresses). Then a BFD session will be established based on the received neighbor parameters.

Dynamic BFD is more flexible than static BFD. In dynamic BFD, routing protocols trigger the setup of BFD sessions, preventing the configuration errors caused by manual configuration. Dynamic BFD is easy to configure and applies to the scenarios where BFD needs to be configured on the entire network. Dynamic BFD for IS-IS can fast detect neighbor status changes and implement fast network convergence.

NOTE:

A BFD session currently does not detect route switching. If the change of bound peer IP address causes a route to switch to another link, the BFD session is negotiated again only when the original link fails.

The priority of BFD configured on an interface is higher than that of BFD configured for a process. If BFD session parameters are configured for both a process and an interface, the parameters on the interface will be used to establish a dynamic BFD session.

Procedure

  • Configure dynamic BFD for IS-IS in a specified IS-IS process.
    1. Run system-view

      The system view is displayed.

    2. Run bfd

      BFD is enabled globally.

    3. Run quit

      The system view is displayed.

    4. Run isis process-id

      The IS-IS view is displayed.

    5. Run bfd all-interfaces enable

      BFD for IS-IS is enabled to establish a BFD session.

      This command enables an IS-IS process to use default BFD parameters to create BFD sessions on all the interfaces in the IS-IS process.

    6. (Optional) Run bfd all-interfaces { min-rx-interval receive-interval | min-tx-interval transmit-interval | detect-multiplier multiplier-value | frr-binding } *

      The parameters for establishing BFD sessions are set for all interfaces.

      The command execution result is applicable to BFD session parameters on all IS-IS interfaces.

    7. (Optional) Run the following command in the interface view: isis bfd block

      The interface is prohibited from dynamically establishing a BFD session.

      By default, an interface can dynamically establish BFD sessions.

    8. Run commit

      The configuration is committed.

  • Configure dynamic BFD for IS-IS on a specified interface.
    1. Run system-view

      The system view is displayed.

    2. Run bfd

      BFD is enabled globally.

    3. Run quit

      The system view is displayed.

    4. Run interface interface-type interface-number

      The interface view is displayed.

    5. On an Ethernet interface, run undo portswitch

      The interface is switched to Layer 3 mode.

      By default, an Ethernet interface works in Layer 2 mode.

      The mode switching function takes effect when the interface only has attribute configurations (for example, shutdown and description configurations). Alternatively, if configuration information supported by both Layer 2 and Layer 3 interfaces exists (for example, mode lacp and lacp system-id configurations), no configuration that is not supported after the working mode of the interface is switched can exist. If unsupported configurations exist on the interface, delete the configurations first and then run the undo portswitch command.

      NOTE:

      If many Ethernet interfaces need to be switched to Layer 3 mode, run the undo portswitch batch interface-type { interface-number1 [ to interface-number2 ] } &<1-10> command in the system view to switch these interfaces to Layer 3 mode in batches.

    6. Run isis bfd enable

      BFD is enabled on the interface to establish a BFD session.

      After BFD is configured globally and the neighbor status is Up (on a broadcast network, DIS is in the Up state), default BFD parameters will be used to establish BFD sessions on the specified interface.

    7. (Optional) Run isis bfd { min-rx-interval receive-interval | min-tx-interval transmit-interval | detect-multiplier multiplier-value | frr-binding } *

      Run this command when BFD session parameters need to be configured for a specified interface.

    8. (Optional) Run isis bfd block

      The interface is prohibited from dynamically establishing a BFD session.

    9. Run commit

      The configuration is committed.

Verifying the Configuration

After BFD is enabled on both ends of a link, run the display isis [ process-id | vpn-instance vpn-instance-name ] bfd session { peer ip-address | all | interface interface-type interface-number } command. The command output shows that BFD status is up.

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Updated: 2019-04-20

Document ID: EDOC1100074760

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