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Question 321

Which IEEE wireless standard, commonly known as Wi-Fi 6, introduced Orthogonal Frequency Division Multiple Access (OFDMA) and target wake time to improve high-density efficiency?

1. IEEE 802.11n
2. IEEE 802.11ac
3. IEEE 802.11ax
4. IEEE 802.11ad

Correct Answer: 3

Explanation:

The IEEE 802.11ax wireless standard, designated commercially as Wi-Fi 6, was designed specifically to address high-density deployment challenges in enterprise environments, public venues, and dense residential areas. Unlike legacy standards, 802.11ax operates across both the 2.4 GHz and 5 GHz frequency bands and introduces advanced technologies such as Orthogonal Frequency Division Multiple Access (OFDMA) and Target Wake Time (TWT). OFDMA subdivides channels into smaller resource units, allowing an access point to simultaneously transmit data to multiple clients with varying bandwidth requirements. Target Wake Time optimizes power consumption by allowing access points and client devices to negotiate specific times to wake up and exchange data, significantly extending battery life for mobile and IoT devices.

Question 322

What happens to a switch port configured with port security when an unauthorized device is connected and the violation mode is set to shutdown?

1. The inbound frames are silently dropped without notification.
2. The unauthorized traffic is dropped, and a syslog warning message is logged.
3. The port transitions into an error-disabled state and shuts down completely.
4. The switch automatically reassigns the unauthorized device to the native VLAN.

Correct Answer: 3

Explanation:

Cisco switch port security provides three distinct violation modes: Protect, Restrict, and Shutdown. When port security is configured with the default shutdown violation mode, any physical interface receiving traffic from an unauthorized MAC address exceeding the configured secure address limit immediately triggers a security violation. In response, the switch shuts down the physical interface entirely, placing it into an error-disabled (err-disabled) state. This halts all traffic transmission through that port until a network administrator manually intervenes by executing shutdown followed by no shutdown on the interface, or configures an automated error-recovery timeout timer.

Question 323

What is the function of an IPv6 solicited-node multicast address?

1. Delivering packets to all routers residing on the local network link simultaneously.
2. Performing efficient address resolution and duplicate address detection without querying every host on the network.
3. Routing global unicast packets across public internet boundaries.
4. Testing the local host protocol stack without utilizing physical network media.

Correct Answer: 2

Explanation:

The IPv6 solicited-node multicast address is a specialized multicast address utilized extensively by the Neighbor Discovery Protocol to perform efficient address resolution (replacing IPv4 ARP) and duplicate address detection. Every IPv6 unicast or anycast address has a corresponding solicited-node multicast address, which is constructed by combining the prefix ff02::1:ff00:0/104 with the final 24 bits of the device’s unicast address. When a host needs to resolve a Layer 2 MAC address for a target IPv6 address, it sends a Neighbor Solicitation message to this specific solicited-node multicast group. Because only nodes whose lowest 24 bits match will listen to that multicast address, unnecessary processing overhead on unrelated hosts across the local network segment is completely avoided.

Question 324

What numerical range represents Extended IPv4 Access Control Lists in Cisco IOS?

1. 1 to 99
2. 100 to 199
3. 200 to 299
4. 1300 to 1999

Correct Answer: 2

Explanation:

In Cisco IOS routing architecture, Access Control Lists are categorized into standard and extended types, each identified by specific numerical ranges. Extended Access Control Lists are assigned numbers ranging from 100 to 199 (and expanded ranges from 2000 to 2699). Unlike standard ACLs (which examine only source IP addresses), extended ACLs evaluate a comprehensive set of packet header parameters, including source and destination IP addresses, upper-layer protocols (such as TCP, UDP, and ICMP), and specific source or destination TCP/UDP port numbers. This granular inspection capability allows network administrators to enforce precise security policies and filter traffic effectively at the source.

Question 325

How does the Spanning Tree Protocol (STP) determine which port becomes the Designated Port on a shared segment between two switches?

1. By selecting the port attached to the switch with the highest MAC address.
2. By selecting the port belonging to the switch with the lowest path cost toward the root bridge.
3. By selecting the port that boots up first during system initialization.
4. By selecting the port configured with the highest port priority value.

Correct Answer: 2

Explanation:

In Spanning Tree Protocol topology calculations, a Designated Port is chosen on every network segment (such as a shared hub or switch link) to forward traffic toward that segment. The election of a Designated Port is determined by evaluating the lowest path cost to the root bridge from the competing switches on that segment. The switch advertising the lowest total root path cost on its interface wins the Designated Port role for that link. If both switches advertise identical root path costs, the STP algorithm breaks the tie by evaluating their Bridge IDs, selecting the port on the switch with the lower Bridge ID as the Designated Port.

Question 326

Which UDP ports are utilized by default for Dynamic Host Configuration Protocol (DHCP) server and client communications?

1. Ports 53 and 54
2. Ports 67 and 68
3. Ports 69 and 70
4. Ports 161 and 162

Correct Answer: 2

Explanation:

Dynamic Host Configuration Protocol operates by default over User Datagram Protocol ports 67 and 68. Specifically, UDP port 67 is utilized by DHCP servers to listen for and process incoming lease requests from client workstations, while UDP port 68 is utilized by DHCP clients to receive configuration parameters, IP addresses, and lease acknowledgments. Because DHCP communication occurs before client endpoints possess configured IP addresses, these packets are transmitted across broadcast domains utilizing UDP transport encapsulation.

Question 327

What is the default OSPF dead interval timer on multi-access broadcast networks, such as Ethernet?

1. 10 seconds
2. 20 seconds
3. 30 seconds
4. 40 seconds

Correct Answer: 4

Explanation:

The Open Shortest Path First routing protocol utilizes dead interval timers to monitor the operational status of neighboring router adjacencies. On multi-access broadcast networks and point-to-point links, the default OSPF hello interval is set to 10 seconds, and the corresponding dead interval is automatically set to 40 seconds—exactly four times the hello interval. If a router fails to receive an incoming OSPF Hello packet from an established neighbor before the 40-second dead timer expires, it declares that neighbor dead, tears down the adjacency, and recalculates the network topology to route traffic around the failed link.

Question 328

Which TCP control flag is combined with the ACK flag during the second step of the standard three-way handshake?

1. FIN
2. RST
3. SYN
4. PSH

Correct Answer: 3

Explanation:

The standard Transmission Control Protocol three-way handshake establishes a reliable session through a structured exchange of control flags. In the first step, the client transmits a segment with the SYN (Synchronize) flag set. In the second step, the server responds with a segment containing both the SYN and ACK (Acknowledgment) flags set, acknowledging the client’s sequence number while synchronizing its own sequence parameters. In the final step, the client returns an ACK segment confirming the connection. This synchronization process ensures that both communicating hosts agree upon initial sequence numbers before application data transfer begins.

Question 329

What metric parameter does EIGRP utilize to prevent routing loops and identify valid backup paths in its dual algorithm?

1. Hop count limit
2. Feasible distance and reported distance condition
3. Administrative distance weighting
4. Maximum transmission unit size

Correct Answer: 2

Explanation:

The Enhanced Interior Gateway Routing Protocol utilizes advanced loop-prevention mechanisms governed by the Diffusing Update Algorithm and the Feasibility Condition. EIGRP evaluates whether a neighboring router qualifies as a Feasible Successor (a valid backup path) by comparing its Reported Distance against the local router’s current Feasible Distance. Specifically, if a neighbor’s Reported Distance is strictly less than the local router’s Feasible Distance, that path is guaranteed to be loop-free, allowing the router to instantly switch traffic to the backup path without triggering diffusing computations during primary link failures.

Question 330

What is the default configuration register value stored in NVRAM on Cisco routers under normal operational conditions?

1. 0x2100
2. 0x2102
3. 0x2120
4. 0x2142

Correct Answer: 2

Explanation:

The Cisco configuration register is a 16-bit software register stored in non-volatile random-access memory that dictates router startup behavior. Under normal operational conditions, the configuration register is set to 0x2102, instructing the router to load the Cisco IOS image from flash memory and load the saved startup configuration file from NVRAM into active RAM upon booting. During password recovery procedures, technicians temporarily modify this value to 0x2142 to bypass the startup configuration file entirely, allowing access to the command-line interface without entering a password.

Question 331

What is the primary operational function of VTP (VLAN Trunking Protocol) Transparent mode?

1. Synchronizing VLAN database updates across all switches in the domain automatically.
2. Blocking VLAN creation locally while accepting server advertisements.
3. Preventing local VLAN database synchronization while forwarding VTP update messages transparently across trunk ports.
4. Encrypting all VLAN trunking control frames against unauthorized interception.

Correct Answer: 3

Explanation:

VLAN Trunking Protocol operates in three distinct modes: Server, Client, and Transparent. When a switch is configured in Transparent mode, it does not participate in VTP database synchronization or update its own local VLAN configuration from advertisements received from VTP servers. However, transparent switches continue to forward VTP configuration messages transparently out their active trunk ports to other switches in the management domain. Additionally, switches in transparent mode are the only ones permitted to create, modify, or delete extended-range VLANs (numbers 1005 to 4094).

Question 332

Which Syslog severity level corresponds to a Warning condition that indicates potential future operational problems?

1. Level 2
2. Level 3
3. Level 4
4. Level 5

Correct Answer: 3

Explanation:

Syslog severity levels follow a standardized numerical scale from 0 to 7, where lower numbers indicate higher operational severity. Level 4 corresponds to “Warning” (often logged as warn), indicating that a potential hazard or condition has been detected that could lead to system impairment if left unaddressed. The complete scale progresses from Level 0 (Emergency), Level 1 (Alert), Level 2 (Critical), Level 3 (Error), Level 4 (Warning), Level 5 (Notice), Level 6 (Informational), up to Level 7 (Debugging). Warning messages enable system administrators to investigate anomalies before they escalate into active service outages.

Question 333

What is the total number of usable host IP addresses available in an IPv4 subnet utilizing a /29 CIDR prefix?

1. 2 hosts
2. 6 hosts
3. 14 hosts
4. 30 hosts

Correct Answer: 2

Explanation:

A /29 CIDR prefix corresponds to an IPv4 subnet mask of 255.255.255.248, where twenty-nine bits are allocated to network identification and three bits remain available for host device addressing. To calculate the total number of IP addresses in this subnet, determine two raised to the power of the host bits (two to the power of 3), which yields 8 total addresses in the block. Out of these 8 total addresses, two are permanently reserved for structural functions: the lowest address serves as the network identifier, and the highest address functions as the directed broadcast address. Subtracting these two reserved addresses leaves exactly 6 usable host IP addresses available for assignment within that specific subnet range.

Question 334

Which Layer 2 switching forwarding method inspects only the destination MAC address of an incoming frame before initiating immediate forwarding out the exit port?

1. Store-and-forward switching
2. Fragment-free switching
3. Cut-through switching
4. Adaptive switching

Correct Answer: 3

Explanation:

Cut-through switching is a high-speed Ethernet forwarding method where the switch reads only the first six bytes of an incoming frame—containing the destination MAC address—and immediately initiates forwarding out the appropriate destination port without waiting for the rest of the frame to arrive. While cut-through switching minimizes latency across enterprise networks, it lacks error-checking capabilities because it does not examine the Frame Check Sequence trailer. Consequently, corrupted or damaged frames are forwarded downstream, whereas store-and-forward switching buffers the entire frame to verify data integrity before forwarding.

Question 335

What primary operational difference distinguishes TACACS+ from RADIUS authentication protocols regarding transport layer communication?

1. TACACS+ operates over UDP, whereas RADIUS operates over TCP.
2. TACACS+ operates over TCP port 49, whereas RADIUS operates over UDP ports 1812 and 1813.
3. TACACS+ encrypts only password fields, whereas RADIUS encrypts the entire packet body.
4. TACACS+ is an open IETF standard, whereas RADIUS is proprietary to Cisco Systems.

Correct Answer: 2

Explanation:

TACACS+ and RADIUS are both AAA security protocols, but they differ significantly in transport layer architecture. TACACS+ operates over Transmission Control Protocol (TCP) port 49, providing reliable connection-oriented transport, and encrypts the entire packet body after initial negotiation for maximum security. In contrast, RADIUS operates over User Datagram Protocol (UDP) ports 1812 (for authentication and authorization) and 1813 (for accounting), utilizing connectionless transport and historically encrypting only the password field within access-request packets.

Question 336

What type of Network Address Translation (NAT) maps a single unique private IP address to a single unique public IP address on a permanent 1-to-1 basis?

1. Port Address Translation
2. Dynamic NAT
3. Static NAT
4. NAT Overload

Correct Answer: 3

Explanation:

Static NAT is a specialized form of Network Address Translation designed to map a single internal private IP address to a single external public IP address on a permanent, unchanging 1-to-1 basis. This translation configuration is essential when internal network devices—such as web servers, mail servers, or database repositories—must remain accessible from external public networks using consistent, predictable IP addresses. Unlike Port Address Translation (NAT Overload) which shares a single public IP across multiple hosts using unique ports, Static NAT requires a dedicated public IP address for each internal host mapped.

Question 337

At which OSI layer do CDP and LLDP neighbor discovery protocols operate?

1. Layer 1 (Physical Layer)
2. Layer 2 (Data Link Layer)
3. Layer 3 (Network Layer)
4. Layer 4 (Transport Layer)

Correct Answer: 2

Explanation:

Cisco Discovery Protocol and Link Layer Discovery Protocol operate exclusively at Layer 2 (the Data Link layer) of the OSI reference model. Both protocols operate independently of Layer 3 network protocols, transmitting periodic multicast frames out physical interfaces to advertise device identities, hardware capabilities, and interface configurations to directly connected adjacent peers. Because they operate at Layer 2, neighbor discovery protocols can establish adjacencies and share telemetry across unconfigured or misconfigured IP subnets as long as physical data link connectivity is functional.

Question 338

What does a lower Stratum level signify in Network Time Protocol (NTP) hierarchical architecture?

1. Greater distance and lower synchronization accuracy relative to the primary reference clock.
2. Closer proximity to an authoritative time source, such as an atomic clock or GPS receiver, indicating higher precision.
3. Slower packet transmission speed across wide area network links.
4. Higher encryption levels applied to time synchronization packets.

Correct Answer: 2

Explanation:

Network Time Protocol utilizes a hierarchical system of clock sources organized into numbered levels known as strata. Stratum 0 devices comprise authoritative, highly accurate physical clock hardware such as atomic clocks, radio clocks, or GPS receivers. Stratum 1 servers are directly connected to Stratum 0 devices. Each subsequent stratum level represents a hop away from the primary source, where Stratum 2 servers synchronize with Stratum 1 servers, and so forth. A lower numerical stratum level signifies closer proximity to the authoritative reference clock, ensuring higher timekeeping precision across enterprise network devices.

Question 339

Which EtherChannel negotiation mode configuration on a Cisco switch forces the interface to negotiate bundling actively regardless of the remote partner’s settings when utilizing PAgP?

1. Desirable
2. Auto
3. On
4. Passive

Correct Answer: 1

Explanation:

When configuring EtherChannel link aggregation using Cisco’s proprietary Port Aggregation Protocol (PAgP), switch ports can be set to either auto or desirable modes. The desirable mode actively initiates negotiations by transmitting PAgP packets out the interface, inviting the remote switch to form an aggregated bundle. If the remote switch is configured in either desirable or auto mode, a successful EtherChannel is established. Conversely, auto mode is passive; the switch waits quietly for incoming PAgP packets before responding. Configuring both connecting ports as auto prevents negotiation from occurring, resulting in unbundled links.

Question 340

Which ICMPv6 message type replaces ARP requests in IPv6 networks to determine a neighbor’s physical MAC address?

1. Router Solicitation
2. Router Advertisement
3. Neighbor Solicitation
4. Neighbor Advertisement

Correct Answer: 3

Explanation:

In IPv6 architecture, the legacy IPv4 Address Resolution Protocol is completely replaced by the Neighbor Discovery Protocol operating over ICMPv6. When a host needs to resolve the physical Layer 2 MAC address of an adjacent node, it transmits an ICMPv6 Neighbor Solicitation message (message type 135) to the target’s solicited-node multicast address. The target node responds directly with an ICMPv6 Neighbor Advertisement message (message type 136) containing its physical hardware address, allowing secure and efficient address resolution without utilizing traditional broadcast storms.