Configuring BFD for BGP4+
BFD for BGP4+ provides BGP4+ with a fast fault detection mechanism, which speeds up network convergence.
Usage Scenario
BFD is dedicated to fast detection of forwarding faults to ensure QoS of voice, video, and other video-on-demand services on a network. It enables service providers to provide users with required VoIP and other real-time services of high availability and scalability.
BGP4+ periodically sends messages to a peer to detect the status of the peer. This process takes more than one second. When traffic is transmitted at gigabit rates, fault detections that take so long add up and eventually cause packet loss. Because of this issue, the system cannot meet the high reliability requirements of the carrier-class network.
To address this problem, configure BFD for BGP4+. BFD for BGP4+ detects faults on links between BGP4+ peers within milliseconds. If a fault is detected, it notifies BGP of the fault. Therefore, BGP4+ routes can undergo fast convergence.
Pre-configuration Tasks
Before configuring BFD for BGP4+, complete the following tasks:
Configure link layer protocol parameters and IP addresses for interfaces to ensure that the link layer protocol on the interfaces is Up.
- Configure basic BGP4+ functions.
Procedure
- Run system-view
The system view is displayed.
- Run bfd
BFD is enabled globally.
- Run quit
Return to the system view.
- Run bgp as-number
The BGP view is displayed.
- Run peer { group-name | ipv6-address } bfd enable [ single-hop-prefer ] [ compatible ]
BFD is configured for a peer or peer group, and default BFD parameters are used to establish a BFD session.
- (Optional) Run peer { group-name | ipv6-address } bfd { min-tx-interval min-tx-interval | min-rx-interval min-rx-interval | detect-multiplier multiplier } *
Various parameters used for establishing BFD sessions are set.
If BFD is configured on a peer group, the peers that are in the peer group but are not configured with the peer bfd block command establish BFD sessions.
- A BFD session can be established only when the corresponding BGP session is in the Established state.
- The configuration of a peer takes precedence over that of its peer group. If BFD is not configured on a peer while its peer group is enabled with BFD, the peer inherits the BFD configurations of its peer group.
- (Optional) Run peer ipv6-address bfd block
A peer is prevented from inheriting the BFD configuration of its peer group.
If BFD is enabled on a peer group, all its peers will inherit the BFD configuration of the peer group and create a BFD session. If you do not want a peer to inherit the BFD configuration of its peer group, you can run this command.
The peer ipv6-address bfd block command and the peer ipv6-address bfd enable command are mutually exclusive. After being configured with the peer bfd block command, a device automatically deletes the BFD session established with a specified peer.
- Run commit
The configuration is committed.
Checking the Configuration
After configuring the route server function, verify the configuration.
Run the display bgp ipv6 bfd session { [ vpnv6 vpn-instance vpn-instance-name ] peer ipv6-address | all } command to check BFD sessions established by BGP4+.
Run the display bgp [ vpnv6 vpn-instance vpn-instance-name ] peer [ ipv6-address ] [ verbose ] command to check BGP4+ peers.