Network+ Networking Concepts: 389 practice questions

12 of the 389 Networking Concepts questions in the Certsqill Network+ bank, shown in full below. Each one carries an explanation for every option, not just the correct one — the wrong answers are where the marks go.

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1. Fiber carries light without electromagnetic coupling: Which feature directly addresses that requirement?

1. Shielded copper limits electromagnetic coupling.

   Shielding reduces interference, but copper remains a conductive signaling medium.
2. Twisted pair rejects some noise.

   Twisting improves noise rejection, but the cable still carries electrical signals through the interference zone.
3. A repeater regenerates weakened signals after a long cable run.

   Regeneration addresses attenuation and timing, not copper’s susceptibility to electrical interference.
4. Fiber carries light without electromagnetic coupling. ✓

   Fiber uses light through nonconductive glass, avoiding electromagnetic interference and ground-potential issues.

Fiber directly avoids electromagnetic interference because it carries data as light through nonconductive glass.

2. A MAC address identifies the network interface: Which addressing feature provides that local-link identificati

1. An IP address identifies the device’s logical network location.

   IP identifies logical Layer 3 locations and supports routing, but it is not the local Ethernet interface identifier.
2. A TCP port identifies the receiving application process.

   TCP ports distinguish application endpoints after delivery reaches a host, not the local interface itself.
3. A MAC address identifies the network interface on the local link. ✓

   Ethernet uses MAC addresses to identify interfaces for delivery across the local data-link segment.
4. A DNS name provides a human-readable name for network resolution.

   DNS names resolve through a service and do not directly identify an Ethernet interface on the local link.

MAC addressing identifies interfaces for delivery across the same Ethernet link.

3. The destination IP address guides routing across: Which feature determines the logical next-hop path?

1. The destination IP address guides routing across interconnected networks. ✓

   Routers examine logical IP destinations and select forwarding paths between different networks.
2. The TCP destination port selects the route through the network.

   TCP ports identify applications, while routers use network-layer destination information for forwarding decisions.
3. The destination MAC address remains usable across every routed link.

   MAC addresses apply locally and are replaced as packets traverse each router-connected link.
4. The DNS record determines the packet’s hop-by-hop forwarding path.

   DNS can resolve names to addresses, but routers use destination IP information for forwarding.

Routers use destination IP information to forward traffic between separate networks.

4. Ports: Which feature distinguishes their simultaneous transport conversations?

1. Routes select destination networks, not application conversations sharing one host address.

   Routing determines network paths and does not distinguish multiple transport sessions terminating at one host.
2. Ports ✓

   Transport-layer port numbers distinguish application conversations sharing the same host IP address.
3. DNS names resolve hosts or services but do not uniquely separate active transport conversations.

   DNS supports naming and resolution, while transport ports separate concurrent application conversations.
4. MAC addresses identify local interfaces, not individual simultaneous application conversations.

   MAC addresses identify interfaces on a local link and do not multiplex applications on one host.

Transport ports multiplex concurrent application conversations that share a host address.

5. Translation: Which conceptual function is required?

1. Framing

   Framing packages data for a data link and does not translate application formats.
2. Translation ✓

   Presentation-layer translation converts data representations so different systems can interpret exchanged information.
3. Routing

   Routing forwards packets between networks but leaves application representation conversion to another function.
4. Port multiplexing

   Port multiplexing identifies application conversations, but it does not convert their data formats.

Presentation translation converts differing data representations into mutually interpretable formats.

6. HTTP provides the request-and-response service used: Which application-layer service is required?

1. SMTP transfers electronic mail between mail clients and mail servers.

   SMTP supports electronic mail transfer and is unrelated to retrieving hypertext pages from a web server.
2. SNMP exchanges management information with monitored network devices and management systems.

   SNMP supports device monitoring and management, not browser-style retrieval of departmental hypertext resources.
3. HTTP provides the request-and-response service used to retrieve hypertext resources from the web server. ✓

   HTTP is the application protocol that defines requests and responses for retrieving web resources.
4. DHCP automatically supplies hosts with addresses and other startup configuration information.

   DHCP configures hosts, but it does not provide the web-resource retrieval service described.

HTTP supplies the application service for requesting and receiving hypertext resources after name resolution and connectivity exist.

7. Encapsulate the transport segment inside an IP packet: Which encapsulation action is required?

1. Encapsulate the application data inside a transport segment by adding ports and transport control.

   Transport encapsulation adds ports and transport control before network-layer encapsulation occurs.
2. Convert the application payload into a presentation format before assigning logical addresses.

   Presentation conversion changes representation and does not provide the network-layer header needed for routing.
3. Encapsulate the IP packet inside an Ethernet frame by adding local-link delivery information.

   Ethernet framing occurs for a link transmission, but it does not add the requested logical routing information.
4. Encapsulate the transport segment inside an IP packet by adding a network-layer header. ✓

   The network layer encapsulates transport data in an IP packet and adds logical addressing for routing.

Network-layer encapsulation adds an IP header around transport data, supplying logical addresses for routing.

8. A UDP datagram provides lightweight: Which transport unit is appropriate?

1. An IP packet provides network-layer delivery but does not define the requested transport behavior.

   IP handles logical delivery, while the requirement concerns transport overhead and retransmission behavior.
2. An Ethernet frame provides local-link delivery but cannot supply end-to-end transport semantics.

   Ethernet frames support one link and do not provide transport-level connection or loss-handling behavior.
3. A UDP datagram provides lightweight, connectionless delivery without built-in retransmission. ✓

   UDP offers low overhead and does not provide TCP-style connection establishment or retransmission guarantees.
4. A TCP segment provides ordered, reliable delivery through acknowledgments and retransmissions.

   TCP supplies reliability and ordering, adding overhead contrary to the stated tolerance for loss and minimal overhead.

UDP datagrams minimize transport overhead when applications tolerate loss and do not need built-in retransmission.

9. Physical-layer signaling: Which OSI feature directly handles representing bits as electrical or optical signal

1. Network-layer logical addressing and routing

   The network layer selects paths using logical addresses; it does not define the medium’s signal representation.
2. Physical-layer signaling ✓

   The physical layer represents bits as electrical, radio, or optical signals across the transmission medium.
3. Application protocol exchange

   Application protocols define user-facing services, but they do not create the electrical or optical signals traveling through media.
4. Data-link framing and MAC addressing

   The data-link layer creates frames and uses local-link addresses after physical signaling already carries the bits.

Physical signaling is the OSI function that converts bits into signals suitable for transmission across the selected medium.

10. An IP address routes traffic between subnets: Which identifier provides the logical addressing needed for deli

1. An IP address routes traffic between subnets. ✓

   Routers use destination IP information to forward traffic between networks.
2. A switch port identifier

   A switch port identifies a local interface, not a destination network or host across routed boundaries.
3. A MAC address identifies a local-link interface.

   A MAC address identifies an interface on the local link; routers replace link-layer headers across routed hops.
4. A VLAN identifies a local broadcast domain.

   A VLAN identifies local segmentation but does not uniquely route traffic to a remote subnet.

IP addresses provide logical addressing for routing between subnets; MAC addresses identify local-link interfaces.

11. Endpoint physical interface failure: Which fault is most directly indicated?

1. A duplex negotiation mismatch between each workstation and switch

   Duplex problems can cause poor performance after link detection, not usually absent carrier and LEDs.
2. A VLAN configuration mismatch affecting the workstation ports

   A VLAN mismatch can block forwarding after link establishment, but it does not normally remove carrier detection or link LEDs.
3. Endpoint physical interface failure ✓

   Absent carrier after testing the switch port and cable directly indicates failed endpoint physical hardware, such as the interface or transceiver.
4. An incorrect IPv4 or IPv6 configuration on the workstations

   Addressing settings affect Layer 3 communication but cannot prevent physical link detection.

Known-good switching and cabling plus absent carrier indicate endpoint physical hardware.

12. Transport port numbers multiplex conversations: Which transport function lets the host distinguish those conve

1. MAC learning maps local addresses to ports.

   MAC learning maps local destination addresses to switch ports and does not identify host application conversations.
2. Transport port numbers multiplex conversations. ✓

   TCP and UDP port numbers identify transport endpoints so multiple services can share one IP address.
3. VLAN tagging separates broadcast domains.

   VLAN tags separate broadcast domains but do not identify individual services sharing one IP address.
4. IP routing

   IP routing selects destinations between networks but does not distinguish multiple application conversations on one host.

Transport port numbers distinguish simultaneous service conversations that share one host IP address.

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