The answer to question 01: Time Between Failures on Average (MTBF). The bathtub curve is a graph of failures over time that tends to be shaped like a bathtub because failures are more probable early or late in an appliance's service life than in the middle. The answer to question 02: IEEE 802.3ad/802.1ax port bonding/Link Aggregation Control Protocol (LACP) The answer to question 03: At all levels, including power, cabling/adapter teaming, switching, routing, and name services/addressing, redundancy and failover must be provided. To make application and database servers fault resilient, cluster services and load balancers can be used.