Using BFD to detect routing failures

Kaspersky SD-WAN supports the Bidirectional Forwarding Detection (BFD) protocol for fast (within one second) detection of network connectivity problems on links and tunnels. When a problem is detected, BFD relays information about the problem from the data plane to the control plane.

Between BFD peers, a BFD session is established, as part of which they exchange control packets to detect network connectivity problems. If problems with network connectivity occur, the BFD session on the SD-WAN interface of the CPE device is terminated, after which route tables are rebuilt.

The table of BFD peers is displayed in the CPE template and on the device:

• To display the table of BFD peers in a CPE template, go to the SD-WAN → CPE templates menu section, click the template, and in the displayed settings area, select the BFD settings tab.
• To display the table of BFD peers on a CPE device, go to the SD-WAN → CPE menu section, click the device, and in the displayed settings area, select the BFD settings tab.

Information about BFD peers is displayed in the following columns of the table:

• Name is the name of the BFD peer.
• IP address is the IPv4 address of the BFD peer.
• Transmit interval (msec.) is the interval in milliseconds for sending control packets from the CPE device to the BFD peer.
• Receive interval (msec.) is the interval in milliseconds for receiving control packets from the BFD peer on the CPE device. If no control packets are received from the BFD peer within the specified time, the CPE device considers the peer unavailable.
• Multiplier is the multiplier of the time interval for sending control packets specified in the BFD peer settings. This multiplier determines the number of milliseconds for which the CPE device must wait for receipt of control packets from the BFD peer. If no control packets are received from the BFD peer within this time, the device announces a network connectivity problem.
• Management contains the actions that can be performed with the BFD peer.