Specifies the Maximum Client Lead Time (MCLT, per draft-ietf-dhc-failover section 2.2) -- the longest a server can unilaterally extend a client's lease beyond what its failover partner knows about -- and can only be changed while the failover facility is out of service. Operators raise MCLT to give more autonomy during brief communication interruptions, at the cost of a longer safe-period before entering partner-down state.