CompTIA A+ Core 1 220-1201 Practice Test

Answer choices

1. A. TCP drops bad segments and never attempts recovery
2. B. TCP can detect corruption with checksum and recover reliability through retransmission
3. C. TCP uses only link-layer CRC and no transport-layer checks
4. D. TCP requires applications to repair bit-level corruption themselves

Wrong-answer review

• A. TCP drops bad segments and never attempts recovery: This statement is incorrect because TCP does attempt recovery through retransmission and checksum verification, not by dropping bad segments.
• C. TCP uses only link-layer CRC and no transport-layer checks: TCP uses transport-layer checks such as checksums to detect corruption, not just link-layer CRC.
• D. TCP requires applications to repair bit-level corruption themselves: Applications do not handle bit-level corruption; TCP manages this with its own mechanisms like checksums and retransmission.

Answer choices

1. A. Cellular data continues unchanged
2. B. Only outgoing data is blocked
3. C. Only MMS is blocked
4. D. Cellular data is disabled until cellular service is turned back on

Wrong-answer review

• A. Cellular data continues unchanged: This option incorrectly suggests that cellular data remains active under Airplane Mode, which contradicts the behavior of disabling all cellular functions until manually re-enabled.
• B. Only outgoing data is blocked: Outgoing data alone is not blocked; rather, all cellular data services are disabled when Airplane Mode is activated.
• C. Only MMS is blocked: MMS blocking is too narrow a description. Under Airplane Mode, all cellular data functionality is suspended until reactivated.

Answer choices

1. A. DHCP is a protocol that assigns IP addresses to devices on a network dynamically.
2. B. DHCP is a file transfer protocol used for transferring files between computers.
3. C. DHCP is a routing protocol used for determining the best path for data packets.
4. D. DHCP is a security protocol used for encrypting data in transit.

Wrong-answer review

• B. DHCP is a file transfer protocol used for transferring files between computers.: This option incorrectly identifies DHCP as a file transfer protocol, which is unrelated to its actual function of dynamically assigning IP addresses.
• C. DHCP is a routing protocol used for determining the best path for data packets.: This option mistakenly describes DHCP as a routing protocol, when it actually handles dynamic IP address assignment for devices on a network.
• D. DHCP is a security protocol used for encrypting data in transit.: This choice wrongly labels DHCP as a security protocol focused on data encryption, whereas DHCP's role is in managing and assigning IP addresses.

Answer choices

1. A. Static channel lock
2. B. NAT traversal
3. C. DHCP relay
4. D. Numeric comparison

Wrong-answer review

• A. Static channel lock: Static channel lock pertains to secure communication channels but does not involve user verification of numeric values, making it irrelevant for Bluetooth LE Secure Connections pairing.
• B. NAT traversal: NAT traversal is unrelated to Bluetooth LE Secure Connections pairing mechanisms because it deals with network address translation rather than secure device authentication.
• C. DHCP relay: DHCP relay forwards DHCP messages and does not involve secure Bluetooth pairing processes; instead, it is unrelated to establishing a secure connection between devices.

Answer choices

1. A. Application layer
2. B. Physical layer
3. C. Data link layer
4. D. Transport layer

Wrong-answer review

• A. Application layer: The Application layer handles application-specific data and protocols, focusing on user applications rather than the transport of data. TCP operates at a lower level to ensure reliable delivery, not here.
• B. Physical layer: The Physical layer deals with electrical signals and physical connections, unrelated to higher-level functions like reliability or flow control managed by TCP in the Transport layer. This layer does not provide end-to-end services because it focuses on hardware specifications rather than data transfer reliability.
• C. Data link layer: The Data Link layer manages communication between adjacent nodes using MAC addresses and frame transmission. It focuses on local network connections rather than providing reliable data transfer across networks as TCP does.

Answer choices

1. A. Enhanced screen refresh rates without sacrificing power efficiency
2. B. Increased battery capacity within a lighter design
3. C. Complete elimination of charging needs
4. D. Longer battery life with increased device weight

Wrong-answer review

• A. Enhanced screen refresh rates without sacrificing power efficiency: Enhanced screen refresh rates are unrelated to battery power density and do not directly impact the capacity of the battery.
• C. Complete elimination of charging needs: Higher power density does not eliminate the need for charging; it only improves efficiency and capacity within a lighter design, making this option incorrect.
• D. Longer battery life with increased device weight: Increased device weight contradicts the goal of higher power density, which aims to reduce weight while maintaining or improving battery capacity.

Answer choices

1. A. TCP relies on UDP to recover lost segments
2. B. TCP has no sequence numbering
3. C. TCP intentionally drops out-of-order traffic without recovery
4. D. TCP uses checksums to detect corruption and retransmits missing data

Wrong-answer review

• A. TCP relies on UDP to recover lost segments: TCP does not rely on UDP for recovery; it independently manages error detection and retransmission, making this option incorrect. This contrasts with TCP's use of checksums and sequence numbering to ensure data integrity.
• B. TCP has no sequence numbering: TCP uses sequence numbering to maintain order and reliability in data transmission, which this option incorrectly denies. This highlights a common misconception about the essential features of TCP.
• C. TCP intentionally drops out-of-order traffic without recovery: TCP buffers out-of-order packets until they can be correctly sequenced, rather than dropping them without recovery.

Answer choices

1. A. Passive-only mode
2. B. Forced fallback mode
3. C. Alternate Mode
4. D. Legacy hub mode

Wrong-answer review

• A. Passive-only mode: Passive-only mode supports only passive cables and cannot negotiate non-USB protocols like DisplayPort because it lacks the necessary Alternate Mode capability.
• B. Forced fallback mode: "Forced fallback mode" is a misleading term; USB Type-C uses Alternate Mode to negotiate non-USB protocols. This distractor confuses with terminology that does not exist in USB Type-C specifications, whereas Alternate Mode directly supports such protocols.
• D. Legacy hub mode: Legacy hub mode pertains to older USB standards and cannot support the Alternate Mode feature for running DisplayPort or other non-USB protocols, making it outdated and irrelevant. Instead, use Alternate Mode as specified in current USB Type-C standards.

Answer choices

1. A. By using a transport-layer checksum
2. B. By relying only on application-layer retries
3. C. By using DHCP transaction IDs
4. D. By checking Ethernet MAC addresses

Wrong-answer review

• B. By relying only on application-layer retries: Incorrect because TCP uses a transport-layer checksum to detect corruption, not application-layer retries.
• C. By using DHCP transaction IDs: Incorrect because DHCP transaction IDs are used for unique identification of DHCP requests and responses, unrelated to TCP's corruption detection which uses transport-layer checksums.
• D. By checking Ethernet MAC addresses: Incorrect as Ethernet MAC addresses identify network devices at the data link layer; TCP operates at the transport layer and employs a checksum mechanism rather than relying on lower-level addressing.

Answer choices

1. A. It is a quick way to disable wireless transmitters and then selectively re-enable approved radios
2. B. It is a replacement for endpoint security controls
3. C. It only affects app notifications
4. D. It forces all apps offline permanently

Wrong-answer review

• B. It is a replacement for endpoint security controls: This option incorrectly assumes Airplane Mode can replace endpoint security controls. Airplane Mode only temporarily disables wireless transmitters, whereas endpoint security controls provide comprehensive protection against threats and are not related to connectivity management.
• C. It only affects app notifications: Incorrect, as Airplane Mode affects more than just app notifications—it impacts all wireless connections initially before selective re-enabling, making this statement too narrow in scope. Airplane Mode disables Wi-Fi, Bluetooth, and cellular data by default, affecting overall device communication rather than just notification services.
• D. It forces all apps offline permanently: False, since Airplane Mode does not force apps offline permanently but allows for the selective re-enablement of approved radios, which contradicts the idea of permanent disconnection.