Appendix B. Memory Tables Answer Key

Maximum tolerable downtime (MTD): The maximum amount of time that an organization can tolerate a single resource or function being down. This is also referred to as maximum period time of disruption (MPTD).

Mean time to repair (MTTR): The average time required to repair a single resource or function when a disaster or disruption occurs.

Mean time between failure (MTBF): The estimated amount of time a device will operate before a failure occurs. This amount is calculated by the device vendor. System reliability is increased by a higher MTBF and lower MTTR.

Recovery time objective (RTO): The shortest time period after a disaster or disruptive event within which a resource or function must be restored to avoid unacceptable consequences. RTO assumes that an acceptable period of downtime exists. RTO should be smaller than MTD.

Work recovery time (WRT): The difference between RTO and MTD, which is the remaining time that is left over after the RTO before reaching the maximum tolerable.

Recovery point objective (RPO): The point in time to which the disrupted resource or function must be returned.

Table 1-4 Administrative (Management) Controls

Table 1-5 Logical (Technical) Controls

Table 1-6 Physical Controls

Chapter 2

Table 2-1 RAID

Table 2-2 Confidentiality, Integrity, and Availability Potential Impact Definitions

Chapter 3

Table 3-4 Symmetric Algorithm Strengths and Weaknesses

Table 3-5 Asymmetric Algorithm Strengths and Weaknesses

Table 3-6 Symmetric Algorithms Key Facts

Table 3-7 Protection Requirements for Cryptographic Keys

Table 3-8 Fire Extinguisher Classes

Chapter 4

Table 4-1 Common TCP/UDP Port Numbers

Table 4-2 Classful IP Addressing

Table 4-3 Private IP Address Ranges

Table 4-4 WPA and WPA2

Table 4-5 Twisted-Pair Categories

Table 4-6 Selected Fiber Specifications

Table 4-7 Ethernet Implementations