bfd bind peer-ipv6

Function

The bfd bind peer-ipv6 command creates a BFD6 session to detect IPv6 links.

The undo bfd bfd-name command deletes a specified BFD6 session.

By default, no BFD6 session is created for IPv6 links.

Format

bfd session-name bind peer-ipv6 ipv6-address [ vpn-instance vpn-instance-name ] [ interface interface-type interface-number ] [ source-ipv6 ipv6-address ]

undo bfd session-name

Parameters

Parameter	Description	Value
session-name	Specifies the name of a BFD6 session.	The value is a string of 1 to 15 case-sensitive characters without spaces. NOTE: When double quotation marks are used around the string, spaces are allowed in the string.
peer-ipv6 ipv6-address	Specifies the peer IPv6 address bound to a BFD6 session.	-
vpn-instance vpn-instance-name	Specifies the name of a VPN instance bound to a BFD6 session.	The value must be an existing VPN instance name.
interface interface-type interface-number	Specifies the local Layer 3 outbound interface bound to a BFD6 session. interface-type specifies the interface type. interface-number specifies the interface number.	-
source-ipv6 ipv6-address	Specifies the source IPv6 address carried in BFD packets. Generally, you do not need to set this parameter. If you do not specify the source IP address, the system automatically sets the source IP address according to the following rules: During BFD for IPv6 session negotiation, if the source IPv6 address is not specified, the system searches the local routing table for an outbound interface from which the peer IP address is reachable. The IPv6 address of this outbound interface is used as the source IP address of the BFD packets sent by the local end. If this parameter is not specified when a BFD for IPv6 session is detecting links, the system uses a fixed source IPv6 address in BFD packets. NOTE: When BFD is used with Unicast Reverse Path Forwarding (URPF), you must manually configure the source IPv6 address in BFD packets because URPF checks the source IPv6 address in received packets.	-

Views

System view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

To fast detect and monitor IPv6 links, you can create BFD for IPv6 sessions.

When creating a BFD for IPv6 binding, pay attention to the following points:

If only the peer IPv6 address is specified, BFD is configured to detect the multi-hop link.
A single-hop link is detected if both the peer IPv6 address and the local interface are specified. That is, a BFD6 session detects a specific route with this interface as the outbound interface and with the peer IPv6 address as the next hop address.
If both the peer IPv6 address and the VPN instance are specified, the created BFD6 session detects the multi-hop links in the VPN instance.
The single-hop links in a VPN instance are detected if both the peer IPv6 address, VPN instance, and local interface are specified.

The source-ipv6 parameter prevents BFD packets from being discarded incorrectly by URPF. The system checks only the source IPv6 address type (it cannot be a multicast or broadcast address), but does not check the address correctness. Therefore, you must manually check the correctness of the source IPv6 address.

When a multi-hop BFD6 session is configured, the value of peer-ipv6 or source-ipv6 cannot be the IPv6 address of a GRE tunnel interface.

Prerequisites

Global BFD has been enabled using the bfd command in the system view.

Follow-up Procedure

After creating a BFD for IPv6 session and entering its view, perform the following mandatory operations:

Run the discriminator command to set the local and remote discriminators for the BFD for IPv6 session.
Run the commit command to commit the configuration.

Perform the following optional operations according to your needs:

Run the description command to configure description for the BFD for IPv6 session.
Run the min-tx-interval command to set the interval for sending BFD for IPv6 packets.
Run the min-rx-interval command to set the interval for receiving BFD for IPv6 packets.
Run the detect-multiplier command to set the local detection multiplier.
Run the process-pst command to configure the Port State Table (PST) of the BFD session.
Run the wtr command to set the Wait-to-Recovery (WTR) time for the BFD for IPv6 session.

Precaution

The BFD for IPv6 session detects links bidirectionally, so the bfd bind peer-ipv6 command must be run on both ends of each link.
After a BFD for IPv6 session is created:
- If you change the source IPv6 address of outbound interface during session negotiation, the source IPv6 address in BFD packets is also changed.
- If you change the source IPv6 address of outbound interface during session detection, the source IPv6 address in BFD packets is not changed.

Example

# Create a BFD6 session named atob to detect a single-hop link.

<HUAWEI> system-view
[HUAWEI] bfd
[HUAWEI-bfd] quit
[HUAWEI] bfd atob bind peer-ipv6 2001::1 interface vlanif 10
[HUAWEI-bfd-session-atob] discriminator local 1
[HUAWEI-bfd-session-atob] discriminator remote 2
[HUAWEI-bfd-session-atob] commit

# Create a BFD6 session named atoc to detect a multi-hop link from which BFD6 packets reach 2001::1.

<HUAWEI> system-view
[HUAWEI] bfd 
[HUAWEI-bfd] quit 
[HUAWEI] bfd atoc bind peer-ipv6 2001::1
[HUAWEI-bfd-session-atoc] discriminator local 3
[HUAWEI-bfd-session-atoc] discriminator remote 4
[HUAWEI-bfd-session-atoc] commit