Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 141
BFD Sessions
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Field Description Detection Multiplier The number of packets that must be missed in order to declare a session down. Length The entire length of the BFD packet. My Discriminator A random number generated by the local system to identify the session. Your Discriminator A random number generated by the remote system to identify the session. Discriminator values are necessary to identify the session to which a control packet belongs because there can be many sessions running on a single interface. Desired Min TX Interval The minimum rate at which the local system would like to send control packets to the remote system. Required Min RX Interval The minimum rate at which the local system would like to receive control packets from the remote system. Required Min Echo The minimum rate at which the local system would like to receive echo packets. RX NOTE: The Dell Networking OS does not currently support the echo function. Authentication Type, Authentication Length, Authentication Data An optional method for authenticating control packets. NOTE: The Dell Networking OS does not currently support the BFD authentication function. Two important parameters are calculated using the values contained in the control packet. Transmit interval Detection time Transmit interval is the agreed-upon rate at which a system sends control packets. Each system has its own transmit interval, which is the greater of the last received remote Desired TX Interval and the local Required Min RX Interval. Detection time is the amount of time that a system does not receive a control packet, after which the system determines that the session has failed. Each system has its own detection time. • In Asynchronous mode: Detection time is the remote Detection Multiplier multiplied by greater of the remote Desired TX Interval and the local Required Min RX Interval. • In Demand mode: Detection time is the local Detection Multiplier multiplied by the greater of the local Desired Min TX and the remote Required Min RX Interval. BFD Sessions BFD must be enabled on both sides of a link in order to establish a session. The two participating systems can assume either of two roles: Active Passive The active system initiates the BFD session. Both systems can be active for the same session. The passive system does not initiate a session. It only responds to a request for session initialization from the active system. A BFD session has two modes: Asynchronous mode In Asynchronous mode, both systems send periodic control messages at an agreed upon interval to indicate that their session status is Up.' Bidirectional Forwarding Detection (BFD) 141
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