pim ipv6 bfd

Function

The pim ipv6 bfd command configures PIM BFD (IPv6) parameters on an interface.

The undo pim ipv6 bfd command restores default PIM BFD (IPv6) parameters on an interface.

By default, the interval for transmitting BFD packets and interval for receiving BFD packets are 1000 ms, and the BFD detection multiplier is 3.

Format

pim ipv6 bfd { min-tx-interval tx-value | min-rx-interval rx-value | detect-multiplier multiplier-value }^*

undo pim ipv6 bfd { min-tx-interval | min-rx-interval | detect-multiplier }^*

undo pim ipv6 bfd { min-tx-interval tx-value | min-rx-interval rx-value | detect-multiplier multiplier-value }^*

Parameters

Parameter	Description	Value
min-tx-interval tx-value	Specifies the interval for sending BFD packets.	The value is an integer that ranges from 100 to 1000, in milliseconds. After the set service-mode enhanced command is configured on the S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, and S6720-HI, the value ranges from 3 to 1000. After the set service-mode enhanced-bfd command is configured on the S5732-H, S6730-H, S6730S-H, S6730-S, and S6730S-S, the value ranges from 3 to 1000.
min-rx-interval rx-value	Specifies the interval for receiving BFD packets.	The value is an integer that ranges from 100 to 1000, in milliseconds. After the set service-mode enhanced command is configured on the S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, and S6720-HI, the value ranges from 3 to 1000. After the set service-mode enhanced-bfd command is configured on the S5732-H, S6730-H, S6730S-H, S6730-S, and S6730S-S, the value ranges from 3 to 1000.
detect-multiplier multiplier-value	Specifies the local detection multiplier of BFD packets. For a stable link, you can set the detection multiplier to a large value to avoid frequent link detection. For an unstable link, a small detection multiplier may cause BFD session flapping. Therefore, it is recommended that you set the detection multiplier to a large value.	The value is an integer ranging from 3 to 50. The default value is 3.

Parameter

Description

Value

min-tx-interval tx-value

Specifies the interval for sending BFD packets.

The value is an integer that ranges from 100 to 1000, in milliseconds.

After the set service-mode enhanced command is configured on the S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, and S6720-HI, the value ranges from 3 to 1000.
After the set service-mode enhanced-bfd command is configured on the S5732-H, S6730-H, S6730S-H, S6730-S, and S6730S-S, the value ranges from 3 to 1000.

min-rx-interval rx-value

Specifies the interval for receiving BFD packets.

The value is an integer that ranges from 100 to 1000, in milliseconds.

After the set service-mode enhanced command is configured on the S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, and S6720-HI, the value ranges from 3 to 1000.
After the set service-mode enhanced-bfd command is configured on the S5732-H, S6730-H, S6730S-H, S6730-S, and S6730S-S, the value ranges from 3 to 1000.

detect-multiplier multiplier-value

Specifies the local detection multiplier of BFD packets.

For a stable link, you can set the detection multiplier to a large value to avoid frequent link detection.
For an unstable link, a small detection multiplier may cause BFD session flapping. Therefore, it is recommended that you set the detection multiplier to a large value.

The value is an integer ranging from 3 to 50. The default value is 3.

Views

GE interface view, XGE interface view, MultiGE interface view, 25GE interface view, 40GE interface view, 100GE interface view, Eth-Trunk interface view, VLANIF interface view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

If you need to control detection parameters of BFD packets, run the pim ipv6 bfd command to configure the sending interval, receiving interval, and local detection multiplier for PIM BFD (IPv6) packets.

The min-tx-interval, min-rx-interval, and detect-multiplier parameters can be configured separately at two ends of a link so that the two ends can send or receive BFD packets at different rates. If there is no special requirement for the detection period and the link is stable, you are advised to configure the same parameter settings for the routing devices that have the same performance and are on the shared network segment.

Prerequisites

IPv6 multicast routing has been enabled globally using the multicast ipv6 routing-enable command in the system view.

Configuration Impact

After BFD parameters are configured, PIM (IPv6) provides the address to be detected, the minimum sending interval and receiving interval of PIM BFD (IPv6) packets, and the local detection multiplier for BFD. The two ends enabled with BFD then negotiate the actual sending interval and receiving interval, and the detection period based on these configured parameters. During the detection phase, BFD notifies the route management (RM) module of the BFD session status and the RM module then notifies PIM (IPv6) of the session status.

If a link fault occurs, BFD quickly notifies the RM of the session status and the RM then notifies PIM (IPv6) of the session status. The PIM (IPv6) protocol deletes the status of the faulty interface, triggers a new DR or Assert election, and restores the forwarding of multicast data to the downstream interface. This shortens the period of multicast traffic interruption caused by the interface fault.

Precautions

To validate PIM BFD (IPv6), ensure that a BFD session has been set up and the session is in the Up state.

The two ends negotiate the actual sending interval and receiving interval, and detection period of BFD packets based on the following negotiation mechanism:

The formula used to calculate the interval for sending PIM IPv6 BFD packets and the formula used to calculate the interval for receiving PIM IPv6 BFD packets are as follows:
- Interval for sending PIM IPv6 BFD packets = Max (Local min-tx-interval, Remote min-rx-interval)
- Interval for receiving PIM IPv6 BFD packets = Max (Remote min-tx-interval, Local min-rx-interval)
The formula used to calculate the detection period is as follows:
- Detection period = Remote detect-multiplier x Max (Remote min-tx-interval, Local min-rx-interval)

If a large parameter value is set, BFD will take a long time to detect a fault on a link. This may cause packet loss.

Example

# Enable PIM BFD (IPv6) on VLANIF 100, and set both the minimum interval for sending BFD packets and the minimum interval for receiving BFD packets to 200 ms and the local detection multiplier to 5.

<HUAWEI> system-view
[HUAWEI] bfd
[HUAWEI-bfd] quit
[HUAWEI] multicast ipv6 routing-enable
[HUAWEI] interface vlanif 100
[HUAWEI-Vlanif100] ipv6 enable
[HUAWEI-Vlanif100] pim ipv6 sm
[HUAWEI-Vlanif100] pim ipv6 bfd enable
[HUAWEI-Vlanif100] pim ipv6 bfd min-tx-interval 200 min-rx-interval 200 detect-multiplier 5

# Enable PIM BFD (IPv6) on GE0/0/1, and set both the minimum interval for sending BFD packets and the minimum interval for receiving BFD packets to 200 ms and the local detection multiplier to 5.

<HUAWEI> system-view
[HUAWEI] bfd
[HUAWEI-bfd] quit
[HUAWEI] multicast ipv6 routing-enable
[HUAWEI] interface gigabitethernet 0/0/1
[HUAWEI-GigabitEthernet0/0/1] undo portswitch
[HUAWEI-GigabitEthernet0/0/1] ipv6 enable
[HUAWEI-GigabitEthernet0/0/1] pim ipv6 sm
[HUAWEI-GigabitEthernet0/0/1] pim ipv6 bfd enable
[HUAWEI-GigabitEthernet0/0/1] pim ipv6 bfd min-tx-interval 200 min-rx-interval 200 detect-multiplier 5