Which benefit do computer networks primarily provide?
A Store files only
B Execute programs
C Exchange information
D Control power
Answer: C. Exchange information. Networks let connected devices exchange data and share resources.
How many layers are defined in the OSI reference model?
A Seven layers
B Six layers
C Eight layers
D Five layers
Answer: A. Seven layers. The OSI reference model has seven conceptual layers.
What does the physical layer transmit?
A Application requests
B Frames and packets
C MAC addresses
D Bits as signals
Answer: D. Bits as signals. The physical layer carries bits as electrical, optical, or radio signals.
How does an Ethernet switch usually forward a known unicast frame?
A IP routing table
B MAC address table
C Port-number table
D DNS cache
Answer: B. MAC address table. A Layer 2 switch consults its forwarding database of MAC addresses and ports.
Which task is a router designed to perform?
A Store web pages
B Connect IP networks
C Run application code
D Filter every frame
Answer: B. Connect IP networks. Routers forward IP packets between networks using routing information.
A MAC address identifies which kind of item on a link?
A CPU process
B DNS zone
C Layer 2 interface
D Transport session
Answer: C. Layer 2 interface. A MAC address is used to identify a link-layer interface on a local network.
How many bits are in an IPv4 address?
A 32 bits
B 16 bits
C 64 bits
D 128 bits
Answer: A. 32 bits. IPv4 addresses are 32 bits long.
What is the length of an IPv6 address?
A 48 bits
B 64 bits
C 32 bits
D 128 bits
Answer: D. 128 bits. IPv6 uses 128-bit addresses.
Which service best describes TCP?
A Broadcast delivery only
B Unreliable datagrams
C Reliable ordered byte stream
D Best-effort frames
Answer: C. Reliable ordered byte stream. TCP provides a reliable, ordered byte-stream service between endpoints.
Which transport protocol sends connectionless datagrams?
A TCP
B UDP
C ICMP
D ARP
Answer: B. UDP. UDP sends independent datagrams without TCP’s connection or delivery guarantees.
What does DNS mainly resolve?
A Names to resource records
B Frames to cables
C MACs to switch ports
D Processes to CPU cores
Answer: A. Names to resource records. DNS stores and returns resource records associated with domain names.
What can DHCP provide to a host?
A Web page markup
B Routing algorithms
C Encrypted file storage
D Leased network configuration
Answer: D. Leased network configuration. DHCP can lease an address and provide configuration such as a subnet mask and router.
On an Ethernet LAN, what does ARP map?
A TCP port to process
B IPv4 to link-layer address
C Domain to mail server
D Frame to VLAN name
Answer: B. IPv4 to link-layer address. ARP resolves an IPv4 next-hop address to a link-layer address on the local network.
What does a default gateway provide?
A DNS zone transfer
B Clock synchronization
C Off-subnet next hop
D Local file service
Answer: C. Off-subnet next hop. Hosts send traffic for destinations outside their subnet to a default gateway.
Which description best fits a LAN?
A Long-distance satellite path
B Worldwide carrier core
C Local limited area
D Single application process
Answer: C. Local limited area. A local area network connects devices across a limited local area.
A WAN typically spans what?
A One device chassis
B Single room only
C One process queue
D Wide geographic coverage
Answer: D. Wide geographic coverage. Wide area networks connect sites across larger geographic distances.
What is central to a star topology?
A Central connecting device
B Single shared bus
C Closed ring path
D Full mesh links
Answer: A. Central connecting device. In a star, each endpoint connects to a central hub or switch.
In networking, bandwidth most directly describes what?
A Route hop total
B Maximum data rate
C Packet error count
D Actual delay
Answer: B. Maximum data rate. Bandwidth describes a link’s capacity to carry data, often expressed as a bit rate.
Throughput measures what?
A Achieved data rate
B Maximum cable length
C Address length
D Signal frequency only
Answer: A. Achieved data rate. Throughput is the data rate actually achieved over a connection.
What does latency measure?
A Address space
B Frame size
C End-to-end delay
D Link capacity
Answer: C. End-to-end delay. Latency is the time taken for data to travel between endpoints.
At which TCP/IP layer does IP operate?
A Link layer
B Application layer
C Transport layer
D Internet layer
Answer: D. Internet layer. IP is an Internet-layer protocol in the TCP/IP model.
A TCP or UDP port helps identify what?
A Physical cable
B Transport endpoint
C IP version
D Ethernet manufacturer
Answer: B. Transport endpoint. Transport ports distinguish application endpoints at a host.
What does full-duplex communication allow?
A Alternating frames only
B One-way transfer only
C Broadcast without replies
D Simultaneous two-way transfer
Answer: D. Simultaneous two-way transfer. Full duplex allows sending and receiving at the same time.
What does a repeater do to a weakened signal?
A Regenerates weakened signals
B Stores DNS records
C Assigns port numbers
D Chooses IP routes
Answer: A. Regenerates weakened signals. A repeater regenerates or retransmits signals to extend a physical link.
What is a basic firewall function?
A Rule-based traffic filtering
B Name resolution
C Clock distribution
D Frame regeneration
Answer: A. Rule-based traffic filtering. A firewall applies rules to allow or block network traffic.