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Supported platforms

Vyatta NOS documentation

Learn how to install, configure, and operate Vyatta Network Operating System (Vyatta NOS), which helps to drive our virtual networking and physical platforms portfolio.

BFD operating modes

BFD can operate in any of three available modes: asynchronous, demand, and echo. The three BFD modes are described in the following paragraphs.

  • Asynchronous mode—In this mode, the systems periodically send BFD control packets to one another, and if a number of those packets in a row are not received by the other system in a stipulated time, the session is declared to be down.
  • Demand mode—In this mode, a system has an independent way of verifying that it has connectivity to the other system. After a BFD session is established, such a system may ask the other system to stop sending BFD control packets, except when the system detects the need to verify connectivity explicitly. In such a case, a short sequence of BFD control packets is exchanged. Demand mode may operate independently in each direction or simultaneously.
  • Echo mode—In this mode, packets are transmitted and consumed by the originating system. This mode exercises the forwarding path of the remote end. Echo mode is used when more-aggressive intervals are required.
Note: Ciena supports only the asynchronous mode currently.