High Frequency BFD

Bidirectional Forwarding Detection (BFD) enables networking peers on each end of a link to quickly detect and recover from a link failure. BFD detects and repairs a broken link faster than by waiting for BGP to detect the down link.

Peer link failure detection time through BFD is a minimum of three seconds (1000 ms * 3 = 3 seconds), by default. The minimum fastest detection possible is 500 ms * 3 = 1.5 seconds.

The BFD parameters are user-configurable, for faster failure detection. This gives you the flexibility to choose the frequency of failure detection, as required.

High Frequency BFD Parameters

Field	Description	Range	Default Value
minrx	The minimum rate at which the packets are received	500-4000000 (in milliseconds)	1000
mintx	The minimum rate at which the packets are sent	500-4000000 (in milliseconds)	1000
multi	The detection multiplier used in BFD. For instance, if multi = 3, The value of SE mintx = 500 ms, The value of remote BFD minrx = 500ms, Then the SE will be marked as Down if it does not receive any packets from SE for 3*500 ms.	3-255	3

Configuring BFD Parameters

The BFD parameters are configured in the VRF context.

To configure the same,

1. Login to the Avi Load Balancer shell with your credentials

2. Enter the configure vrfcontext <vrfcontext name> as shown below:

   [admin:abc-ctrl]: > configure vrfcontext global
   Updating an existing object. Currently, the object is:
   +----------------------------+-------------------------------------+
   | Field                      | Value                               |
   +----------------------------+-------------------------------------+
   | uuid                       | vrfcontext-1f42f9e5-2aee-4509-95c8-52a9d994fbe1                                                       |
   | name                       | global                              |
   | bgp_profile                |                                     |
   |   local_as                 | 65000                               |
   |   ibgp                     | True                                |
   |   peers[1]                 |                                     |
   |     remote_as              | 65000                               |
   |     peer_ip                | 100.64.50.21                        |
   |     subnet                 | 100.64.50.0/24                      |
   |     md5_secret             |                                     |
   |     bfd                    | True                                |
   |     advertise_vip          | True                                |
   |     advertise_snat_ip      | False                               |
   |     advertisement_interval | 5                                   |
   |     connect_timer          | 10                                  |
   |     ebgp_multihop          | 0                                   |
   |     shutdown               | False                               |
   |   peers[2]                 |                                     |
   |     remote_as              | 65000                               |
   |     peer_ip                | 100.64.50.3                         |
   |     subnet                 | 100.64.50.0/24                      |
   |     md5_secret             |                                     |
   |     bfd                    | True                                |
   |     advertise_vip          | False                               |
   |     advertise_snat_ip      | True                                |
   |     advertisement_interval | 5                                   |
   |     connect_timer          | 10                                  |
   |     ebgp_multihop          | 0                                   |
   |     shutdown               | False                               |
   |   keepalive_interval       | 60                                  |
   |   hold_time                | 180                                 |
   |   send_community           | True                                |
   |   shutdown                 | False                               |
   | system_default             | True                                |
   | tenant_ref                 | admin                               |
   | cloud_ref                  | Default-Cloud                       |
   +----------------------------+-------------------------------------+

3. A new parameter called bfd_profile is introduced within which the BFD parameters are configured. In the bfd_profile, enter the values for mintx, minrx, and multi.

4. Save the configuration.

   [admin:abc-ctrl]: vrfcontext>
   [admin:abc-ctrl]: vrfcontext>  bfd_profile
   [admin:abc-ctrl]: vrfcontext:bfd_profile> mintx 1500
   [admin:abc-ctrl]: vrfcontext:bfd_profile> minrx 1500
   [admin:abc-ctrl]: vrfcontext:bfd_profile> multi 3
   [admin:abc-ctrl]: vrfcontext:bfd_profile> save
   [admin:abc-ctrl]: vrfcontext> save

The BFD parameters are now configured as per the values entered.

The minimum timeout duration was three seconds in prior releases. The minimum timeout duration as low as 1.5 seconds is supported.