The peer bfd enable command enables a device to establish a BFD session with its peer group using default detection parameter values.
The undo peer bfd enable command cancels this function.
By default, a BGP device does not establish any BFD session with its peer group.
| Parameter | Description | Value |
|---|---|---|
| group-name |
Specifies the name of a peer group. |
The name is a string of 1 to 47 case-sensitive characters, with spaces not supported. When double quotation marks are used around the string, spaces are allowed in the string. |
| single-hop-prefer |
Preferentially creates a single-hop BFD session for BGP peers. |
- |
| compatible |
Indicates the compatibility mode. If this keyword is specified, the TTL in packets sent by BFD is set to 255. |
- |
| per-link |
Establishes a BFD session to monitor the link between member interfaces. |
- |
| one-arm-echo |
Indicates a one-arm BFD echo session. |
- |
Usage Scenario
BGP uses BFD to quickly detect faults in links between BGP peers. This accelerates network convergence. The peer bfd enable command is used to configure a device to establish a BFD session with its peer group using default detection parameter values.
If single-hop-prefer is specified in the command, BGP peers preferentially use the single-hop detection mode when establishing BFD sessions with each other to implement link connectivity detection. Specifically, only one BFD session is created on a specified BGP interface. The single-hop-prefer parameter ensures detection mode consistency between a Huawei device and a non-Huawei device. If a peer is added to a peer group, the peer inherits the BFD configuration of the group, regardless of whether BFD is enabled for the peer. To prevent this peer from inheriting the BFD configuration of the group, run the peer bfd block command for the peer.Prerequisites
A BFD session can be established only when the corresponding BGP peer relationship is in the Established state.
Configuration Impact
After the peer bfd enable command is enabled, peers or peer groups can establish IPv6 BFD sessions using default parameter values. This allows fast link fault detection.
The BFD configuration of a peer takes precedence over that of the peer group to which the peer belongs. If BFD is not configured on a peer and the peer group to which the peer belongs is enabled with BFD, the peer inherits the BFD configurations from the peer group.Precautions
Before enabling BFD on a BGP peer, enable BFD in the system view. If no BFD detection parameter is specified, a BFD session is established using default parameter values.
If the command is run more than once, the latest configuration overrides the previous one. NOTE: The peer bfd block command and the peer bfd enable command are mutually exclusive. After the peer bfd block command is run, the BFD session is deleted automatically.<HUAWEI> system-view [~HUAWEI] ip vpn-instance vpna [*HUAWEI-vpn-instance-vpna] ipv4-family [*HUAWEI-vpn-instance-vpna-af-ipv4] route-distinguisher 100:1 [*HUAWEI-vpn-instance-vpna-af-ipv4] vpn-target 111:1 both [*HUAWEI-vpn-instance-vpna-af-ipv4] quit [*HUAWEI-instance-vpna] quit [*HUAWEI] bgp 100 instance a [*HUAWEI-bgp-instance-a] ipv4-family vpn-instance vpna [*HUAWEI-bgp-instance-a-vpna] group test external [*HUAWEI-bgp-instance-a-vpna] peer test as-number 200 [*HUAWEI-bgp-instance-a-vpna] peer test bfd enable