Cisco CCNA (200-301) Certification Exam | Complete Practice
Questions, Verified Answers & Detailed Explanations
(2026/2027)
Question 1
What is the primary function of the Transport layer (Layer 4) of the OSI
model?
• A. Logical addressing and routing across internetworks
• B. End-to-end communication, flow control, and reliability of data
delivery
• C. Physical transmission of bits over network media
• D. Session establishment and dialog control between applications
Correct Answer: B. End-to-end communication, flow control, and
reliability of data delivery
Detailed Rationale: The Transport layer ensures reliable or best-effort
data transfer across the network, handling flow control, error detection,
and port-to-port communication using protocols like TCP and UDP.
Question 2
You are given an IP address of 192.168.10.45 with a subnet mask of
255.255.255.224. What is the subnet address for this host?
• A. 192.168.10.0
• B. 192.168.10.32
• C. 192.168.10.40
, • D. 192.168.10.64
Correct Answer: B. 192.168.10.32
Detailed Rationale: A subnet mask of 255.255.255.224 (/27) creates
subnet blocks of 32 addresses (0, 32, 64, 96...). Since IP 45 falls between
32 and 63, the network address is 192.168.10.32.
Question 3
Which IPv6 address prefix is reserved for Link-Local addresses, meaning
they are automatically configured and only valid on a single local
network link?
• A. 2000::/3
• B. FC00::/7
• C. FE80::/10
• D. FF00::/8
Correct Answer: C. FE80::/10
Detailed Rationale: Link-Local addresses in IPv6 always begin with
FE80::/10 and are used for neighbor discovery and communication on
the local subnet only; they are never routable across routers.
Question 4
Which type of Ethernet cable is traditionally required to connect two
Cisco switches directly together when Auto-MDIX is disabled?
• A. Straight-through cable
• B. Crossover cable
• C. Rollover cable
, • D. Fiber optic patch cord
Correct Answer: B. Crossover cable
Detailed Rationale: Traditionally, connecting like devices (switch-to-
switch or router-to-router) requires a crossover cable to cross the
transmit and receive pins. Modern switches support Auto-MDIX which
negates this requirement.
Question 5
Which protocol operates at Layer 4 of the OSI model, is connectionless,
provides no guaranteed delivery, and has minimal header overhead?
• A. TCP
• B. UDP
• C. IP
• D. ICMP
Correct Answer: B. UDP
Detailed Rationale: UDP is a connectionless, unreliable transport
protocol that introduces minimal header overhead, making it ideal for
streaming media and real-time voice or video applications.
Question 6
Which IEEE wireless standard introduced support for both 2.4 GHz and
5 GHz frequency bands, offering speeds up to 54 Mbps using OFDM
modulation?
• A. 802.11b
• B. 802.11a
, • C. 802.11g
• D. 802.11ac
Correct Answer: C. 802.11g
Detailed Rationale: 802.11g operates in the 2.4 GHz band and supports
speeds up to 54 Mbps while maintaining backward compatibility with
802.11b devices. (802.11a operates only in the 5 GHz band).
Question 7
On a Cisco switch, what is the default VLAN assigned to all switch ports
out of the box?
• A. VLAN 1
• B. VLAN 10
• C. VLAN 100
• D. VLAN 4094
Correct Answer: A. VLAN 1
Detailed Rationale: VLAN 1 is the default management and native VLAN
on Cisco Catalyst switches. All ports belong to VLAN 1 by default until
explicitly changed.
Question 8
In Spanning Tree Protocol (STP), how is the Root Bridge elected in a
switched network topology?
• A. The switch with the highest MAC address wins.
• B. The switch with the lowest Bridge ID (consisting of Bridge
Priority and MAC address) wins.
Questions, Verified Answers & Detailed Explanations
(2026/2027)
Question 1
What is the primary function of the Transport layer (Layer 4) of the OSI
model?
• A. Logical addressing and routing across internetworks
• B. End-to-end communication, flow control, and reliability of data
delivery
• C. Physical transmission of bits over network media
• D. Session establishment and dialog control between applications
Correct Answer: B. End-to-end communication, flow control, and
reliability of data delivery
Detailed Rationale: The Transport layer ensures reliable or best-effort
data transfer across the network, handling flow control, error detection,
and port-to-port communication using protocols like TCP and UDP.
Question 2
You are given an IP address of 192.168.10.45 with a subnet mask of
255.255.255.224. What is the subnet address for this host?
• A. 192.168.10.0
• B. 192.168.10.32
• C. 192.168.10.40
, • D. 192.168.10.64
Correct Answer: B. 192.168.10.32
Detailed Rationale: A subnet mask of 255.255.255.224 (/27) creates
subnet blocks of 32 addresses (0, 32, 64, 96...). Since IP 45 falls between
32 and 63, the network address is 192.168.10.32.
Question 3
Which IPv6 address prefix is reserved for Link-Local addresses, meaning
they are automatically configured and only valid on a single local
network link?
• A. 2000::/3
• B. FC00::/7
• C. FE80::/10
• D. FF00::/8
Correct Answer: C. FE80::/10
Detailed Rationale: Link-Local addresses in IPv6 always begin with
FE80::/10 and are used for neighbor discovery and communication on
the local subnet only; they are never routable across routers.
Question 4
Which type of Ethernet cable is traditionally required to connect two
Cisco switches directly together when Auto-MDIX is disabled?
• A. Straight-through cable
• B. Crossover cable
• C. Rollover cable
, • D. Fiber optic patch cord
Correct Answer: B. Crossover cable
Detailed Rationale: Traditionally, connecting like devices (switch-to-
switch or router-to-router) requires a crossover cable to cross the
transmit and receive pins. Modern switches support Auto-MDIX which
negates this requirement.
Question 5
Which protocol operates at Layer 4 of the OSI model, is connectionless,
provides no guaranteed delivery, and has minimal header overhead?
• A. TCP
• B. UDP
• C. IP
• D. ICMP
Correct Answer: B. UDP
Detailed Rationale: UDP is a connectionless, unreliable transport
protocol that introduces minimal header overhead, making it ideal for
streaming media and real-time voice or video applications.
Question 6
Which IEEE wireless standard introduced support for both 2.4 GHz and
5 GHz frequency bands, offering speeds up to 54 Mbps using OFDM
modulation?
• A. 802.11b
• B. 802.11a
, • C. 802.11g
• D. 802.11ac
Correct Answer: C. 802.11g
Detailed Rationale: 802.11g operates in the 2.4 GHz band and supports
speeds up to 54 Mbps while maintaining backward compatibility with
802.11b devices. (802.11a operates only in the 5 GHz band).
Question 7
On a Cisco switch, what is the default VLAN assigned to all switch ports
out of the box?
• A. VLAN 1
• B. VLAN 10
• C. VLAN 100
• D. VLAN 4094
Correct Answer: A. VLAN 1
Detailed Rationale: VLAN 1 is the default management and native VLAN
on Cisco Catalyst switches. All ports belong to VLAN 1 by default until
explicitly changed.
Question 8
In Spanning Tree Protocol (STP), how is the Root Bridge elected in a
switched network topology?
• A. The switch with the highest MAC address wins.
• B. The switch with the lowest Bridge ID (consisting of Bridge
Priority and MAC address) wins.
