Cisco CCNA 200-301 Routing and Switching
Official Practice Exam Actual Exam
2026/2027 with Detailed Rationales |
Complete Exam-Style Questions | Pass
Guaranteed – A+ Graded
══════════════════════════════════════
SECTION 1: NETWORK FUNDAMENTALS & OSI/TCP/IP MODELS Q1 – Q10
══════════════════════════════════════
Question 1 of 50
A network engineer is troubleshooting intermittent connectivity between a workstation and a
remote web server. The engineer captures traffic and notices that frames are arriving at the
destination with corrupted FCS values, but the source MAC addresses appear correct. At
which layer of the OSI model is the problem most likely occurring?
A. Layer 1, because cable faults typically corrupt the frame trailer during transmission
B. Layer 2, because the Data Link layer is responsible for frame integrity via FCS ✓ CORRECT
C. Layer 3, because IP header corruption would propagate down and affect the frame trailer
D. Layer 4, because TCP segment errors would cause the NIC to generate invalid FCS values
Correct Answer: B
Rationale: The Frame Check Sequence is calculated and verified at the Data Link layer (Layer
2), so corrupted FCS values indicate a Layer 2 issue such as a faulty NIC, bad cable, or duplex
mismatch. Many engineers instinctively blame Layer 1 for physical corruption, but the FCS
itself is a Layer 2 construct—physical layer problems usually manifest as complete frame
loss rather than corrupted trailers. In practice, running a TDR cable test and checking port
statistics for input errors will quickly isolate whether the root cause is cabling or a failing
interface.
Question 2 of 50
A junior administrator is configuring a new switch and needs to ensure that a connected IP
phone and desktop PC can communicate on separate VLANs using a single switchport. The
administrator recalls that one layer of the TCP/IP model handles both logical addressing and
path determination. Which layer of the TCP/IP model performs these functions?
,A. The Internet layer, which is responsible for logical addressing and routing decisions ✓
CORRECT
B. The Transport layer, which manages end-to-end communication and logical host
identification
C. The Network Access layer, which combines Data Link and Physical layer functions for path
selection
D. The Application layer, which uses logical addressing embedded in application protocols to
route traffic
Correct Answer: A
Rationale: In the TCP/IP model, the Internet layer maps directly to OSI Layer 3 and handles IP
addressing, packet forwarding, and routing decisions across interconnected networks. The
Transport layer manages ports and reliable delivery, not logical addressing or path
determination, which is a common point of confusion for those more familiar with the OSI
model's separation of functions. On the CCNA exam, remember that the TCP/IP Internet layer
consolidates what OSI splits across Network and parts of Transport.
Question 3 of 50
During a late-night maintenance window, a network engineer connects a laptop directly to a
router's console port to push a critical configuration update. The engineer uses a rollover
cable and terminal emulation software set to 9600 baud, 8 data bits, no parity, and 1 stop bit.
Which layer of the OSI model best describes the function of the rollover cable in this
scenario?
A. Layer 1, because the rollover cable provides the physical electrical path for bit
transmission ✓ CORRECT
B. Layer 2, because the rollover cable encapsulates console data into frames for delivery
C. Layer 3, because the console connection requires IP addressing for management traffic
D. Layer 4, because terminal emulation relies on TCP port 23 for session establishment
Correct Answer: A
Rationale: A rollover cable is a physical layer component that simply carries electrical
signals between the laptop's serial port and the router's console port; it does not perform
framing, addressing, or any higher-layer functions. Some candidates confuse console cables
with Ethernet cables and assume Layer 2 involvement, but console connections are
out-of-band management with no MAC addresses or frames involved. Real-world tip: always
verify your terminal settings—9600/8/N/1 is the Cisco default, but some newer platforms ship
at 115200 baud.
Question 4 of 50
A network architect is designing a new campus network and must choose a topology that
provides redundancy while minimizing the number of physical links. The architect wants to
, ensure that if any single link fails, all switches can still reach each other without re-cabling.
Which topology meets this requirement with the fewest links?
A. A full mesh topology, where every switch has a direct connection to every other switch
B. A partial mesh topology, where each switch connects to at least two others for redundancy
✓ CORRECT
C. A bus topology, where all switches share a single backbone cable with redundant
terminators
D. A star topology, where all switches connect through a central hub with dual power supplies
Correct Answer: B
Rationale: A partial mesh topology provides the redundancy of multiple paths while using
significantly fewer links than a full mesh, making it the practical choice for most campus
designs. A full mesh would require n(n-1)/2 links and becomes prohibitively expensive and
complex as the network grows, which is why it is typically reserved for critical WAN
connections. In production environments, partial mesh is almost always implemented with
Layer 3 routing or Layer 2 protocols like STP to manage the redundant paths.
Question 5 of 50
An enterprise is migrating from a traditional three-tier hierarchical design to a collapsed core
architecture to reduce cost and complexity. The network manager is concerned about how
this change affects the distribution of broadcast traffic. In the collapsed core model, where
does the boundary between Layer 2 and Layer 3 typically occur?
A. At the access layer switches, where VLANs terminate and routing begins ✓ CORRECT
B. At the collapsed core switches, which now perform both distribution and core routing
functions
C. At the WAN edge router, which handles all inter-VLAN routing for the entire campus
D. At the wireless LAN controller, which bridges wireless broadcast domains to wired routed
segments
Correct Answer: A
Rationale: In a collapsed core design, the access layer switches often perform Layer 3
routing at the network edge, creating a routing boundary that contains broadcast domains
locally rather than allowing them to traverse upward. The collapsed core itself combines
distribution and core functions but does not necessarily become the sole Layer 2/Layer 3
boundary, which differs from traditional three-tier designs where distribution switches handle
this role. This architecture is increasingly common in modern campus networks because it
simplifies the topology and reduces the spanning tree domain size.
Question 6 of 50
Official Practice Exam Actual Exam
2026/2027 with Detailed Rationales |
Complete Exam-Style Questions | Pass
Guaranteed – A+ Graded
══════════════════════════════════════
SECTION 1: NETWORK FUNDAMENTALS & OSI/TCP/IP MODELS Q1 – Q10
══════════════════════════════════════
Question 1 of 50
A network engineer is troubleshooting intermittent connectivity between a workstation and a
remote web server. The engineer captures traffic and notices that frames are arriving at the
destination with corrupted FCS values, but the source MAC addresses appear correct. At
which layer of the OSI model is the problem most likely occurring?
A. Layer 1, because cable faults typically corrupt the frame trailer during transmission
B. Layer 2, because the Data Link layer is responsible for frame integrity via FCS ✓ CORRECT
C. Layer 3, because IP header corruption would propagate down and affect the frame trailer
D. Layer 4, because TCP segment errors would cause the NIC to generate invalid FCS values
Correct Answer: B
Rationale: The Frame Check Sequence is calculated and verified at the Data Link layer (Layer
2), so corrupted FCS values indicate a Layer 2 issue such as a faulty NIC, bad cable, or duplex
mismatch. Many engineers instinctively blame Layer 1 for physical corruption, but the FCS
itself is a Layer 2 construct—physical layer problems usually manifest as complete frame
loss rather than corrupted trailers. In practice, running a TDR cable test and checking port
statistics for input errors will quickly isolate whether the root cause is cabling or a failing
interface.
Question 2 of 50
A junior administrator is configuring a new switch and needs to ensure that a connected IP
phone and desktop PC can communicate on separate VLANs using a single switchport. The
administrator recalls that one layer of the TCP/IP model handles both logical addressing and
path determination. Which layer of the TCP/IP model performs these functions?
,A. The Internet layer, which is responsible for logical addressing and routing decisions ✓
CORRECT
B. The Transport layer, which manages end-to-end communication and logical host
identification
C. The Network Access layer, which combines Data Link and Physical layer functions for path
selection
D. The Application layer, which uses logical addressing embedded in application protocols to
route traffic
Correct Answer: A
Rationale: In the TCP/IP model, the Internet layer maps directly to OSI Layer 3 and handles IP
addressing, packet forwarding, and routing decisions across interconnected networks. The
Transport layer manages ports and reliable delivery, not logical addressing or path
determination, which is a common point of confusion for those more familiar with the OSI
model's separation of functions. On the CCNA exam, remember that the TCP/IP Internet layer
consolidates what OSI splits across Network and parts of Transport.
Question 3 of 50
During a late-night maintenance window, a network engineer connects a laptop directly to a
router's console port to push a critical configuration update. The engineer uses a rollover
cable and terminal emulation software set to 9600 baud, 8 data bits, no parity, and 1 stop bit.
Which layer of the OSI model best describes the function of the rollover cable in this
scenario?
A. Layer 1, because the rollover cable provides the physical electrical path for bit
transmission ✓ CORRECT
B. Layer 2, because the rollover cable encapsulates console data into frames for delivery
C. Layer 3, because the console connection requires IP addressing for management traffic
D. Layer 4, because terminal emulation relies on TCP port 23 for session establishment
Correct Answer: A
Rationale: A rollover cable is a physical layer component that simply carries electrical
signals between the laptop's serial port and the router's console port; it does not perform
framing, addressing, or any higher-layer functions. Some candidates confuse console cables
with Ethernet cables and assume Layer 2 involvement, but console connections are
out-of-band management with no MAC addresses or frames involved. Real-world tip: always
verify your terminal settings—9600/8/N/1 is the Cisco default, but some newer platforms ship
at 115200 baud.
Question 4 of 50
A network architect is designing a new campus network and must choose a topology that
provides redundancy while minimizing the number of physical links. The architect wants to
, ensure that if any single link fails, all switches can still reach each other without re-cabling.
Which topology meets this requirement with the fewest links?
A. A full mesh topology, where every switch has a direct connection to every other switch
B. A partial mesh topology, where each switch connects to at least two others for redundancy
✓ CORRECT
C. A bus topology, where all switches share a single backbone cable with redundant
terminators
D. A star topology, where all switches connect through a central hub with dual power supplies
Correct Answer: B
Rationale: A partial mesh topology provides the redundancy of multiple paths while using
significantly fewer links than a full mesh, making it the practical choice for most campus
designs. A full mesh would require n(n-1)/2 links and becomes prohibitively expensive and
complex as the network grows, which is why it is typically reserved for critical WAN
connections. In production environments, partial mesh is almost always implemented with
Layer 3 routing or Layer 2 protocols like STP to manage the redundant paths.
Question 5 of 50
An enterprise is migrating from a traditional three-tier hierarchical design to a collapsed core
architecture to reduce cost and complexity. The network manager is concerned about how
this change affects the distribution of broadcast traffic. In the collapsed core model, where
does the boundary between Layer 2 and Layer 3 typically occur?
A. At the access layer switches, where VLANs terminate and routing begins ✓ CORRECT
B. At the collapsed core switches, which now perform both distribution and core routing
functions
C. At the WAN edge router, which handles all inter-VLAN routing for the entire campus
D. At the wireless LAN controller, which bridges wireless broadcast domains to wired routed
segments
Correct Answer: A
Rationale: In a collapsed core design, the access layer switches often perform Layer 3
routing at the network edge, creating a routing boundary that contains broadcast domains
locally rather than allowing them to traverse upward. The collapsed core itself combines
distribution and core functions but does not necessarily become the sole Layer 2/Layer 3
boundary, which differs from traditional three-tier designs where distribution switches handle
this role. This architecture is increasingly common in modern campus networks because it
simplifies the topology and reduces the spanning tree domain size.
Question 6 of 50
