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JakeMont edited this page Nov 14, 2011 · 1 revision

Description of Status Items

This page contains a brief description of the output of the bfdd-control status command. See the bfdd-control manpage for a description of this command. This document assumes an understanding of the Bidirectional Forwarding Detection (BFD) protocol and refers to items in RFC5880 BFD Base Specification (June 2010).

Note that some items are only available at higher status levels.

Items

  • id - The id of the given session. This id is only used to refer to the session when using bfdd-control commands. This is not used in the actual BFD protocol and is not the same as LocalId

  • local - The local ip address used to send and receive packets for this session. This may be followed by (active) or (passive) depending on what role the session is taking.

  • remote - The remote ip address used to send and receive packets for this session.

  • LocalState - The local Session State (bfd.SessionState in outgoing control packets.) This is followed by the Local Diagnostic value (bfd.LocalDiag) which gives the reason for the most recent state change. This item may also include Forced if the current state is being held using the bfdd-control session state command. This item may also include Suspended if the session is suspended. See bfdd-control manpage for details on suspending sessions.

  • RemoteState - The remote Session State (the "Sta" field in the most recently received control packet.) This is followed by the Remote Diagnostic value (the "Diag" field in the most recently received control packet) which gives the reason for the most recent remote state change.

  • LocalId - The Discriminator used to identify this session in packet exchanges with the remote system (bfd.LocalDiscr, and the "My Discriminator" field in outgoing packets.)

  • RemoteId - The Discriminator used to identify the remote session in packet exchanges with the this system (bfd.RemoteDiscr, and the "My Discriminator" field in incoming packets.)

  • Time - A the amount of time spent in the current state. At higher status levels this may include the time spent in the 4 most recent states.

  • CurrentTxInterval - The interval between sending scheduled control packets. This value is calculated based on a number of other settings.

  • CurrentRxTimeout - The Detection Timeout after which, if no packets are received from the remote system, the session is put into the Down state. This is based on the larger of RemoteDesiredMinTx and LocalRequiredMinRx multiplied by RemoteDetectMulti.

  • LocalDetectMulti - The approximate number of scheduled packets that the remote system can not receive before it will declare the session Down. (bfd.DetectMult and the "Detect Mult" field in outgoing packets.)

  • LocalDesiredMinTx - The lowest interval (highest rate) at which we can (want) to send packets. (bfd.DesiredMinTxInterval and "Desired Min TX Interval" in outgoing packets.) The remote system will expect to receive packets at intervals of, approximately, the larger of this and RemoteRequiredMinRx. When the session is not Up, then the normal value may not be used. In that case the value that will be used when the session is up will be displayed in parenthesis and marked with def. This value can be changed using the bfdd-control session set mintx command. In some cases the new value is not actually used until the remote system acknowledges the change. In these cases the pending value will be displayed in parenthesis and marked with pending.

  • LocalRequiredMinRx -- The lowest interval (highest rate) at which we can (want) to receive packets. (bfd.RequiredMinRxInterval and "Required Min RX Interval" in outgoing packets.) The remote system will send periodic control packets at intervals of, approximately, the larger of this and RemoteDesiredMinTx. This value can be changed using the bfdd-control session set minrx command. In some cases the new value is not actually used (for timeout detection) until the remote system acknowledges the change. In these cases the pending value will be displayed in parenthesis and marked with pending.

  • RemoteDetectMulti - The approximate number of scheduled packets that the local system can not receive before it will declare the session Down. ("Detect Mult" field of the last incoming packet.)

  • RemoteDesiredMinTx - The lowest interval (highest rate) at which the remote system can to send packets. ("Desired Min TX Interval" in the most rectently recieved packet.) Used in calculating CurrentRxTimeout.

  • RemoteRequiredMinRx -- The lowest interval (highest rate) at which the remote system can receive packets. ("Required Min RX Interval" in the most recent incoming packet.) Used in calculating CurrentTxInterval.

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