vrrp6 vrid track bfd-session

Function

The vrrp6 vrid track bfd-session command enables a Virtual Router Redundancy Protocol for IPv6 (VRRP6) backup group to monitor a BFD session.

The undo vrrp6 vrid track bfd-session command disables a VRRP6 backup group from monitoring a BFD session.

By default, a VRRP6 backup group does not monitor a BFD session.

Format

vrrp6 vrid virtual-router-id track bfd-session bfd-session-id [ increased value-increased | reduced value-reduced ]

vrrp6 vrid virtual-router-id track bfd-session session-name bfd-configure-name [ increased value-increased | reduced value-reduced ]

vrrp6 vrid virtual-router-id track bfd-session bfd-session-id { peer | link }

vrrp6 vrid virtual-router-id track bfd-session session-name bfd-configure-name { peer | link }

undo vrrp6 vrid virtual-router-id track bfd-session [ bfd-session-id | session-name bfd-configure-name ]

Parameters

Parameter	Description	Value
virtual-router-id	Specifies the ID of a VRRP6 backup group.	The value is an integer ranging from 1 to 255.
bfd-session-id	Specifies the local discriminator of a monitored BFD session.	The value is an integer ranging from 1 to 16384.
increased value-increased	Specifies a value by which the priority of a router in a VRRP6 backup group increases when a monitored BFD session goes Down.	The value is an integer ranging from 1 to 255. The value 255 is reserved for an IP address owner, and therefore the largest value can be set to 254.
reduced value-reduced	Specifies a value by which the priority of a router in a VRRP6 backup group decreases when a monitored BFD session goes Down.	The value is an integer ranging from 1 to 255. The smallest value can be set to 1. By default, the priority decreases by 10 when a monitored BFD session goes Down.
session-name bfd-configure-name	Specifies the name of a monitored BFD session.	The value is a string of 1 to 64 characters, spaces not supported. When quotation marks are used around the string, spaces are allowed in the string. When the name of a BFD session is configured, the uppercase and lowercase letters in the name must be the same as what you enter. BFD session names are case-insensitive. For example, ABC and abc are regarded as the same BFD session. If you have configured ABC as the name of a BFD session, the ABC BFD session view is directly displayed when you configure abc.
peer	Indicates that a monitored BFD session is a peer BFD session.	-
link	Indicates that a monitored BFD session is a link BFD session.	-

Views

100ge sub-interface view, 100GE interface view, 10GE sub-interface view, 10GE interface view, 200GE sub-interface view, 25GE sub-interface view, 25GE interface view, 400GE sub-interface view, 400GE interface view, 40GE sub-interface view, 40GE interface view, 50GE sub-interface view, 50GE interface view, Eth-Trunk sub-interface view, Eth-Trunk interface view, FlexE interface view, GE optical interface view, GE sub-interface view, GE interface view, GE electrical interface view, Global VE sub-interface view, VE sub-interface view, VLANIF interface view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
vrrp	write

Usage Guidelines

Usage Scenario

If the link between routers in a VRRP6 backup group fails, the VRRP6 backup group performs a master/backup VRRP switchover only after a period of three times the interval at which VRRP6 Advertisement packets are sent. During this period, service data may be lost. BFD can rapidly detect link faults. You can run the vrrp6 vrid track bfd-session command to enable a VRRP6 backup group to monitor a BFD session. When the status of the monitored BFD session changes, the BFD module notifies the VRRP6 module of the change. The VRRP6 module changes the priority or status based on configurations to implement a rapid master/backup VRRP switchover.

To enable a VRRP6 backup group to monitor a common BFD session, run the vrrp6 vrid track bfd-session command. When the BFD module notifies the VRRP6 module of a BFD session status change, the VRRP6 module increases or decreases the priority to implement a master/backup VRRP switchover. Usually, backup routers use BFD sessions to monitor the master router.
To enable a VRRP6 backup group to monitor a peer or link BFD session, run the vrrp6 vrid track bfd-session command. If peer or link BFD detects a fault and the peer or link BFD session goes Down, the BFD module notifies the VRRP6 module of the status change. After receiving the notification, the VRRP6 module directly performs a master/backup VRRP switchover without changing the priority. A VRRP6 router can determine a local or remote link fault based on the status of the peer or link BFD session.

Prerequisites

A VRRP6 backup group has been created using the vrrp6 vrid virtual-ip command.
BFD has been enabled using the bfd command.
A static BFD session has been created using the bfd bind peer-ip command, and a local discriminator has been configured for the static BFD session using the discriminator command. Or a static BFD session with automatically negotiated discriminators has been created using the bfd bind peer-ip source-ip auto command.

Configuration Impact

When you run the vrrp6 vrid virtual-router-id track bfd-session { bfd-session-id | session-name bfd-configure-name } [ increased value-increased | reduced value-reduced ] command to enable a VRRP6 backup group to monitor a BFD session, the specified increased value-increased or reduced value-reduced parameter value affects the status of the VRRP6 backup group. The specified parameter value only needs to ensure that a master/backup VRRP switchover can be performed. For example, if the master router's priority is 120 (which can be viewed using the display vrrp6 brief command) and a backup router's priority is 110, you need to set the increased value-increased parameter to 20 only on the backup router.

After you enable a VRRP6 backup group to monitor a link BFD session, you cannot change the BFD session type. To change the BFD session type, you must first disable the VRRP6 backup group from monitoring the link BFD session.

Precautions

After you enable a VRRP6 backup group to monitor a BFD session, an IP address owner's priority does not change because it is fixed at 255.

The VRRP6 considers that the BFD session detects a Down event in the following situations:

No BFD session is configured on a peer device.
The peer BFD session is shut down.
The peer BFD session is deleted.
BFD session negotiation fails.
The BFD session is Down.
The VRRP6 considers that the BFD session detects an Up event in the following situations:
BFD session negotiation is successful.
The BFD session changes from Down to Up.

Example

# Enable VRRP6 backup group 1 to monitor a BFD session with the local discriminator set to 1.

<HUAWEI> system-view
[~HUAWEI] bfd
[*HUAWEI-bfd] quit
[*HUAWEI] bfd 1 bind peer-ipv6 2001:db8::1 source-ipv6 2001:db8::2 auto
[*HUAWEI-bfd-session-1] quit
[*HUAWEI] interface GigabitEthernet 0/1/1
[*HUAWEI-GigabitEthernet0/1/1] ipv6 enable
[*HUAWEI-GigabitEthernet0/1/1] ipv6 address 2001:db8::2 64
[*HUAWEI-GigabitEthernet0/1/1] vrrp6 vrid 1 virtual-ip FE80::7 link-local
[*HUAWEI-GigabitEthernet0/1/1] vrrp6 vrid 1 track bfd-session 1 reduced 20

# Enable VRRP6 backup group 3 to monitor a peer BFD session on GE 0/1/3.

<HUAWEI> system-view
[~HUAWEI] bfd
[*HUAWEI-bfd] quit
[*HUAWEI] bfd peer1 bind peer-ipv6 2001:db8::1 source-ipv6 2001:db8::2 auto
[*HUAWEI-bfd-session-peer1] quit
[*HUAWEI] interface GigabitEthernet 0/1/3
[*HUAWEI-GigabitEthernet0/1/3] ipv6 enable
[*HUAWEI-GigabitEthernet0/1/3] ipv6 address 2001:db8::2 64
[*HUAWEI-GigabitEthernet0/1/3] vrrp6 vrid 3 virtual-ip FE80::7 link-local
[*HUAWEI-GigabitEthernet0/1/3] vrrp6 vrid 3 track bfd-session session-name peer1 peer

# Enable VRRP6 backup group 2 to monitor a static BFD session named atob with automatically negotiated discriminators.

<HUAWEI> system-view
[~HUAWEI] bfd
[*HUAWEI-bfd] quit
[*HUAWEI] bfd atob bind peer-ipv6 2001:db8::1 source-ipv6 2001:db8::2 auto
[*HUAWEI-bfd-session-atob] quit
[*HUAWEI] interface GigabitEthernet 0/1/2
[*HUAWEI-GigabitEthernet0/1/2] ipv6 enable
[*HUAWEI-GigabitEthernet0/1/2] ipv6 address 2001:db8::2 64
[*HUAWEI-GigabitEthernet0/1/2] vrrp6 vrid 2 virtual-ip FE80::7 link-local
[*HUAWEI-GigabitEthernet0/1/2] vrrp6 vrid 2 track bfd-session session-name atob reduced 20