BSCS : Network Fundamentals 5 — Questions and Answers
Question 1: What type of cable is required for a direct connection between two computers without a switch (a cross-connect)?
- Straight-through cable
- Crossover cable (Correct answer)
- Rollover (console) cable
- Coaxial cable
Correct answer: Crossover cable
A crossover cable swaps the transmit and receive pairs, allowing two similar devices (e.g., two PCs) to communicate directly without an intermediary switch.
Question 2: Which protocol is used to test reachability and round-trip time between two IP hosts?
- SNMP
- FTP
- ICMP (Correct answer)
- SMTP
Correct answer: ICMP
ICMP (Internet Control Message Protocol) echo requests and replies are used by the 'ping' utility to test reachability and measure round-trip time.
Question 3: What is the main difference between a collision domain and a broadcast domain?
- A collision domain is bounded by routers; a broadcast domain is bounded by switches
- A collision domain is bounded by switches; a broadcast domain is bounded by routers (Correct answer)
- Both are bounded by routers
- Both are bounded by hubs
Correct answer: A collision domain is bounded by switches; a broadcast domain is bounded by routers
Switches break up collision domains (each port is its own), while routers break up broadcast domains — frames do not cross router interfaces.
Question 4: Which IPv4 address block is reserved for link-local (APIPA) addressing when DHCP is unavailable?
- 192.168.0.0/16
- 172.16.0.0/12
- 169.254.0.0/16 (Correct answer)
- 10.0.0.0/8
Correct answer: 169.254.0.0/16
Windows and other OSes assign a 169.254.x.x address from the 169.254.0.0/16 range when no DHCP server responds, enabling limited local communication.
Question 5: Which QoS mechanism places packets into multiple queues based on priority and serves higher-priority queues first?
- FIFO queuing
- Priority queuing (PQ) (Correct answer)
- Weighted Fair Queuing (WFQ)
- Traffic shaping
Correct answer: Priority queuing (PQ)
Priority Queuing assigns packets to one of several priority queues and always drains higher-priority queues before lower-priority ones, minimizing latency for critical traffic.
Question 6: What is the primary role of DNS in networking?
- Assign IP addresses to hosts automatically
- Translate human-readable domain names to IP addresses (Correct answer)
- Encrypt web traffic
- Route packets between autonomous systems
Correct answer: Translate human-readable domain names to IP addresses
DNS (Domain Name System) resolves fully qualified domain names (e.g., www.example.com) into IP addresses so hosts can locate each other.
Question 7: In VLAN configuration, what does 802.1Q tagging add to an Ethernet frame?
- A 4-byte tag containing a VLAN ID between the source MAC address and the EtherType field (Correct answer)
- An additional IP header for routing between VLANs
- A CRC checksum for error detection
- A port number for Transport Layer demultiplexing
Correct answer: A 4-byte tag containing a VLAN ID between the source MAC address and the EtherType field
IEEE 802.1Q inserts a 4-byte tag (including a 12-bit VLAN ID) into the Ethernet frame header to identify which VLAN the frame belongs to on trunk links.
BSCS : Network Fundamentals 5
What type of cable is required for a direct connection between two computers without a switch (a cross-connect)?