Cisco Systems Cisco Systems This document defines a set of interval values that we call "Standard intervals". Values of this set must be supported for transmitting BFD control packets and for calculating the detection time in the receive direction when the value is equal or larger than the fastest, i.e. lowest, interval a particular BFD implementation supports. This solves the problem of finding an interval value that both BFD speakers can support while allowing a simplified implementation as seen for hardware-based BFD. It does not restrict an implementation from supporting more intervals in addition to the Standard intervals.