pim ipv6 bfd enable

Usage Scenario

To minimize the impact of a fault on services and improve network availability, a network device is required to quickly detect a communications fault between adjacent devices so that the upper layer protocol can rectify the fault to ensure normal services.

On a PIM network, changes of link status between PIM neighbors will restart some PIM mechanisms, such as DR election or Assert winner election. For example, when the DR or Assert winner on a shared network segment fails, PIM neighbors on the network segment trigger DR or Assert winner re-election only when the PIM neighbor relationships time out. Multicast data transmission is interrupted before a new DR or Assert winner is elected. The multicast service interruption time is longer than or equal to the neighbor relationship timeout interval or Assert timer value, and is usually several seconds.

PIM BFD (IPv6) can detect link status changes on a shared network segment in milliseconds, enabling PIM devices to rapidly respond to failures of PIM neighbors. If a PIM BFD (IPv6)-capable interface does not receive any BFD packets from the DR or Assert winner within the detection interval, it considers that the DR or Assert winner has failed. Then BFD rapidly reports the session status to the route management (RM) module, which then reports the link status change to the PIM module. After receiving the notification, the PIM module triggers DR or Assert winner re-election immediately, without waiting for timeout of the neighbor relationship. This mechanism reduces the multicast service interruption time and improves reliability of multicast data transmission.

Pre-configuration Tasks

PIM BFD (IPv6) depends on the BFD protocol. Therefore, you need first to enable BFD globally to validate the PIM BFD (IPv6) function.

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

Before configuring PIM BFD (IPv6), enable PIM-SM (IPv6) in the interface view. If the undo pim ipv6 sm command is run, IPv6 PIM-SM is disabled and the PIM BFD (IPv6) function is removed from the interface at the same time.