Which one of the following statements regarding Bidirectional Forwarding Detection (BFD) is correct?
Which one of the following statements regarding Bidirectional Forwarding Detection (BFD) is correct?
Bidirectional Forwarding Detection (BFD) has two operational modes: Asynchronous mode and Echo mode. Asynchronous mode involves routers periodically sending control packets to activate and maintain BFD sessions, whereas Echo mode involves sending BFD echo packets. In many implementations, including Cisco routers, BFD echo mode is the default mode of operation.
BFD has the following operational modes. In asynchronous mode routers periodically send control packets to activate and maintain BFD sessions. Asynchronous mode is available in two versions: Asynchronous mode without echo Asynchronous mode with echo (default value on Cisco routers)
correct A: https://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/fs_bfd.html#wp1236440
How to Configure Bidirectional Forwarding Detection You start a BFD process by configuring BFD on the interface. When the BFD process is started, no entries are created in the adjacency database, in other words, no BFD control packets are sent or received. BFD echo mode, which is supported in BFD Version 1 for Cisco IOS 12.4(9)T, is enabled by default. BFD echo packets are sent and received in addition to BFD control packets. The adjacency creation takes places once you have configured BFD support for the applicable routing protocols. This section contains the following procedures: https://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/fs_bfd.html
A is corerct