isis bfd block

Function

The isis bfd block command prevents an interface from dynamically setting up a BFD session.

The undo isis bfd block command enables an IS-IS interface to dynamically set up a BFD session.

By default, the interface is not prevented from dynamically setting up a BFD session.

Format

isis bfd block

undo isis bfd block

Parameters

None

Views

Ethernet interface view, Ethernet sub-interface view, Eth-Trunk interface view, Eth-Trunk sub-interface view, Tunnel interface view, Loopback interface view, Dialer interface view, VLANIF interface view, Virtual-Template interface view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

BFD can provide millisecond-level fault detection, help IS-IS to detect the faults that occur on neighboring devices or links more rapidly, and instruct IS-IS to recalculate routes for correct packet forwarding. The bfd all-interfaces enable command enables all interfaces of a specified IS-IS process to dynamically set up a BFD session. In scenarios where network reliability requirements are not high and links are not stable, if BFD is enabled, data transmission will be interrupted in case of link flapping. To solve this problem, run the isis bfd block command to prevent the interface from dynamically setting up a BFD session.

Configuration Impact

After the isis bfd block command is run on an interface, BFD session will not be set up dynamically for the link to which the interface corresponds, and IS-IS Hello packets are used to detect link faults, slowing down route convergence.

Precautions

If the isis bfd block, isis bfd enable, and isis bfd static commands are run, only the last command takes effect.

Example

# Prevent GigabitEthernet0/0/0 from dynamically setting up a BFD session.

<sysname> system-view
[sysname] interface GigabitEthernet0/0/0
[sysname-GigabitEthernet0/0/0] isis bfd block