A minimum control packet timer transmit interval of 10 ms can be configured. To maximize the reliability of S-BFD connectivity checking in scaled scenarios with short timers, cases where BFD can go down because of normal changes of the next hop of an LSP path at the head end must be avoided. It is therefore recommended that LFA is not configured at the head end LER when using S-BFD with sub-second timers. When the LFA is not configured, protection of the SR-TE LSP is still provided end-to-end by the combination of S-BFD connectivity checking and primary or secondary path protection.
Similar to the case of LDP and RSVP, S-BFD uses a single path for a loose hop; multiple S-BFD sessions for each of the ECMP paths or spraying of S-BFD packets across the paths is not supported. S-BFD is not down until all the ECMP paths of the loose hop go down.