Cisco 200-301 Cisco Certified Network Associate (CCNA) Exam Dumps and Practice Test Questions Set 8 Q106-120
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Question 106
Which type of IPv4 address is used to send data to a single device?
A) Unicast
B) Broadcast
C) Multicast
D) Anycast
Answer: A) Unicast
Explanation
Unicast addressing is a fundamental concept in networking that allows for one-to-one communication between devices. When a packet is sent to a unicast address, it travels from a single source directly to a single destination device. This addressing method ensures that the data reaches only the intended recipient, providing a controlled and reliable way to deliver information across a network. Unicast is the most common type of network communication because the majority of network traffic, including web requests, email delivery, and file transfers, is intended for a specific device rather than multiple recipients. By sending data to a single destination, unicast communication minimizes unnecessary network traffic and ensures efficient use of bandwidth, as packets are not broadcasted to devices that do not require them.
Unicast addresses operate at both the IP and MAC address layers. At the network layer, IPv4 or IPv6 addresses identify the intended recipient of the packet, while at the data link layer, the MAC address ensures that the frame reaches the correct interface on the local network. This combination allows the network to deliver data accurately from one device to another, whether the communication occurs within a local subnet or across multiple networks via routers. Unicast communication also supports protocols that require acknowledgment and reliable delivery, such as Transmission Control Protocol (TCP). TCP relies on unicast addressing to ensure that packets are received, acknowledged, and delivered in the correct sequence, making unicast essential for applications that demand accuracy and consistency.
In contrast, broadcast addresses are used for one-to-all communication within a subnet. When a device sends a packet to a broadcast address, every device on the subnet receives it. Broadcast is useful for tasks such as Address Resolution Protocol (ARP) requests, which help devices discover the MAC addresses associated with specific IP addresses, and for certain network-wide announcements. However, broadcast communication is inefficient for sending data to a single device, as it generates unnecessary traffic and consumes bandwidth on all devices in the subnet.
Multicast addresses, on the other hand, provide one-to-many communication. A single packet can be delivered to a group of devices that have subscribed to a specific multicast group. Multicast is useful for applications such as streaming media, group messaging, and service discovery, where multiple devices need to receive the same data simultaneously. While multicast reduces the network load compared to broadcast for group communications, it is not suitable for communication intended for a single device.
Anycast addressing delivers packets to the nearest device among a set of devices sharing the same address. This approach is commonly used for load balancing and routing optimization in distributed networks, directing traffic to the closest or best-performing server. Anycast does not provide one-to-one communication, as the packet is delivered to one member of the group rather than a specifically targeted device.
Because the question specifies communication to a single device, unicast addressing is the correct choice. It ensures that data is delivered directly to the intended recipient, providing controlled, efficient, and reliable network communication. Unlike broadcast, multicast, or anycast, unicast is uniquely suited for one-to-one interactions, making it essential for most standard network operations, including web browsing, file transfers, and secure device-to-device communication.
Question 107
Which type of cable is used to connect two switches directly?
A) Crossover
B) Straight-through
C) Rollover
D) Fiber patch
Answer: A) Crossover
Explanation
Crossover cables are a specific type of Ethernet cable designed to connect similar types of network devices directly, such as switch-to-switch or router-to-router connections. The key characteristic of a crossover cable is that it swaps the transmit and receive pairs, allowing the transmitting pins on one device to connect directly to the receiving pins on the other device. This wiring arrangement ensures that the devices can communicate without the need for an intermediate device, such as a switch or hub. Crossover cables were historically essential for creating direct links between networking devices of the same type, enabling data to flow correctly between interfaces that expect traffic in opposite directions.
The use of crossover cables is particularly important in scenarios where devices of the same type need to be connected for redundancy, network expansion, or aggregation. For example, connecting two switches directly with a crossover cable allows network administrators to establish an additional path between switches, which can be used for load balancing, redundancy, or linking different parts of a network without requiring a central switch. Similarly, connecting two routers with a crossover cable can enable point-to-point communication for routing experiments, lab setups, or backup connections. By ensuring the transmit and receive signals are properly aligned, crossover cables prevent communication failures that would occur if standard straight-through cables were used in these situations.
In contrast, straight-through cables are designed to connect different types of devices, such as a PC to a switch, a switch to a router, or a computer to a hub. Straight-through cables maintain the same wiring pattern on both ends, which works because the devices at each end of the connection have complementary transmit and receive pin arrangements. While straight-through cables are the most common type of Ethernet cable and are widely used for connecting end devices to network infrastructure, they are not suitable for direct connections between similar devices without the use of auto-MDI/MDIX technology, which many modern devices now support.
Rollover cables, sometimes called console cables, are another type of Ethernet cable used primarily for management purposes. These cables allow administrators to connect a PC or terminal to the console port of a network device, such as a switch or router, for configuration and maintenance. Rollover cables are not used for standard network data communication and are unsuitable for connecting network devices to one another.
Fiber patch cables are used for optical connections between devices equipped with fiber-optic interfaces. These cables are ideal for long-distance or high-speed network connections but require compatible transceivers and ports, and they are not interchangeable with copper-based Ethernet connections. Fiber patch cables also do not provide the specific transmit-receive swapping needed for connecting similar devices with standard Ethernet ports.
Because the question specifies a direct connection between two switches, a crossover cable is the correct choice. It ensures proper alignment of transmit and receive pairs, enabling seamless communication between similar devices without intermediate network equipment. Unlike straight-through, rollover, or fiber patch cables, crossover cables are specifically designed to handle one-to-one connections between devices of the same type, making them essential in scenarios such as switch-to-switch or router-to-router connections.
Question 108
Which command clears the ARP table on a Cisco device?
A) clear arp-cache
B) show arp
C) show mac address-table
D) show ip interface brief
Answer: A) clear arp-cache
Explanation
The clear arp-cache command is used in networking to remove all entries from a device’s ARP table, effectively forcing the device to rebuild the table with current and accurate mappings between IP addresses and MAC addresses. The ARP table, which stores these mappings, is essential for devices to communicate on a local network because it allows a device to resolve the hardware address of a destination when given its IP address. Over time, the ARP table may contain outdated or incorrect entries due to changes in network topology, IP address conflicts, or temporary device unavailability. Stale ARP entries can lead to communication problems, such as packets being sent to the wrong device or network connectivity issues. By using clear arp-cache, administrators can remove these potentially problematic entries, ensuring that the device retrieves fresh ARP information from the network.
When a device clears its ARP cache, it immediately begins the process of rebuilding the table. Any outgoing packets that require MAC address resolution will trigger ARP requests on the local network. Other devices respond with their correct MAC addresses, allowing the requesting device to update its ARP table with accurate mappings. This process ensures that future communication is based on current network conditions, eliminating problems caused by stale or incorrect entries. Clearing the ARP cache is particularly useful in troubleshooting situations where network connectivity is inconsistent or when a device’s IP address has been reassigned. For example, in a scenario where two devices are mistakenly assigned the same IP address, clearing the ARP cache ensures that each device learns the correct MAC address for the given IP, reducing conflicts and preventing data from being misdirected.
The show arp command, in comparison, is used to display the current ARP table on a device. It provides a read-only view of the mappings between IP addresses and MAC addresses, allowing administrators to verify which addresses the device has learned. While show arp is valuable for monitoring and diagnosing network issues, it does not actively modify or clear the ARP table. It is a diagnostic tool rather than a corrective command.
The show mac address-table command provides a similar function but operates at a different layer. It displays MAC addresses learned by a switch and the ports on which the corresponding devices are connected. While this command is important for verifying device connectivity at the data link layer, it does not show the IP-to-MAC mappings stored in the ARP table and cannot clear stale entries.
The show ip interface brief command provides an overview of the device’s interfaces, including IP addresses and operational status. Although this information is useful for understanding which interfaces are active and their assigned addresses, it does not provide ARP information or allow the ARP cache to be cleared.
Because the question specifically asks about clearing the ARP table to force a device to rebuild its mappings, the correct command is clear arp-cache. It directly addresses the need to remove stale or problematic entries, ensuring that future communications are accurate and reliable. None of the other commands—show arp, show mac address-table, or show ip interface brief—perform this clearing function, making clear arp-cache the proper solution for maintaining accurate IP-to-MAC relationships on a network device.
Question 109
Which protocol resolves hostnames to IP addresses?
A) DNS
B) DHCP
C) ARP
D) ICMP
Answer: A) DNS
Explanation
The Domain Name System, commonly referred to as DNS, is an essential component of modern networking that provides the ability to translate human-readable hostnames into IP addresses. Computers and network devices use IP addresses to identify and communicate with one another across networks, but remembering numerical addresses for each website, server, or device would be impractical for humans. DNS solves this problem by acting as a distributed database that maps descriptive hostnames, such as www.example.com, to their corresponding IP addresses, whether IPv4 or IPv6. This translation allows users to access resources easily without needing to memorize complex numerical strings, enabling intuitive navigation of the internet and local networks.
When a user enters a hostname in a web browser or application, the device sends a DNS query to a DNS resolver. The resolver then searches through a hierarchy of DNS servers, starting from the root servers and moving through top-level domain servers, authoritative servers, and cached entries, to find the IP address that matches the requested hostname. Once the resolver retrieves the correct IP address, it returns it to the device, which can then establish a connection using standard IP communication. This process happens quickly and transparently, allowing seamless access to websites, email servers, and other network services. The efficiency and reliability of DNS are critical for the overall functionality of networked systems, as the vast majority of internet and enterprise applications depend on accurate hostname resolution.
In contrast, the Dynamic Host Configuration Protocol, or DHCP, serves a different purpose in networking. DHCP is responsible for dynamically assigning IP addresses and other network configuration parameters, such as subnet masks, default gateways, and DNS server addresses, to devices on a network. While DHCP ensures that devices can communicate on the network without requiring manual configuration, it does not provide the translation of hostnames into IP addresses. DHCP primarily manages IP allocation and network configuration rather than resolving names for human convenience.
Address Resolution Protocol, or ARP, is another protocol that operates at the local network level. ARP is used to map IP addresses to MAC addresses, which are the hardware identifiers used to deliver packets on a local Ethernet network. ARP is essential for local packet delivery and proper communication between devices on the same subnet, but it does not provide a mechanism for translating hostnames into IP addresses. Its function is entirely different from that of DNS.
ICMP, the Internet Control Message Protocol, is also unrelated to hostname resolution. ICMP is used for network diagnostics and error reporting, allowing devices to send messages about connectivity issues, unreachable hosts, or network congestion. Tools such as ping and traceroute rely on ICMP to measure connectivity and network paths, but ICMP does not convert hostnames to IP addresses.
Because the question specifically asks about translating hostnames into IP addresses, DNS is the correct choice. It uniquely provides the function of mapping human-readable names to numerical addresses, enabling users to access network resources conveniently and reliably. Neither DHCP, ARP, nor ICMP offers this capability, making DNS the essential protocol for hostname resolution in networking.
Question 110
Which command verifies connectivity and measures latency to a destination?
A) ping
B) traceroute
C) show ip route
D) show interfaces
Answer: A) ping
Explanation
Ping is a fundamental network utility used to test the connectivity between two devices on a network. It operates by sending Internet Control Message Protocol (ICMP) echo request packets to a specified target host and waiting for echo reply responses. This simple mechanism allows network administrators and users to determine whether a host is reachable, ensuring that there is a functioning path between the source and the destination. Beyond verifying basic connectivity, ping also measures the round-trip time for packets to travel to the target and back, providing valuable information about network latency and the responsiveness of the destination. By using ping, administrators can quickly detect network outages, misconfigurations, or issues that may impact communication between devices.
When a ping is executed, the source device sends an ICMP echo request to the IP address or hostname of the target device. If the target is reachable, it responds with an ICMP echo reply. The source then records the time taken for the packet to complete the round trip, displaying statistics such as minimum, maximum, and average latency. These measurements are crucial for assessing network performance, as higher latency values may indicate congestion, faulty links, or inefficient routing. Ping also reports packet loss, which can reveal network reliability issues. A consistent lack of responses may suggest that the destination is offline, that there are firewall rules blocking ICMP traffic, or that there is a connectivity problem somewhere along the path.
Traceroute is another diagnostic tool that uses ICMP or UDP packets to trace the path that packets take from the source to the destination. While traceroute provides detailed information about each hop along the route, including the IP addresses and response times of intermediary routers, it is primarily focused on path discovery rather than verifying simple end-to-end connectivity. Traceroute is more useful for identifying routing issues, network loops, or bottlenecks along the path, but it is not as direct as ping for testing whether a host is reachable and how quickly it responds.
The show ip route command displays the routing table of a device, including information about directly connected networks, static routes, and routes learned through dynamic routing protocols. While this command is important for understanding how traffic should be routed through the network, it does not actually test whether a destination host is reachable. It only shows the paths known to the device, meaning that the routes may exist even if the destination device is offline or unreachable due to other issues.
Similarly, the show interfaces command provides details about the operational status, IP addresses, and error statistics of network interfaces. It is valuable for diagnosing interface-level problems or monitoring port activity, but it does not verify the reachability of remote hosts. Interface status alone cannot confirm that packets can successfully traverse the network to a specific device.
Because the question specifically asks about verifying connectivity and measuring network latency to a target host, ping is the correct choice. It directly tests whether a host is reachable, provides round-trip time measurements, and reports packet loss, making it an essential tool for both basic connectivity testing and performance analysis. None of the other commands or tools provide the same combination of reachability verification and latency measurement, which is why ping is the most appropriate solution for this scenario.
Question 111
Which command displays the running configuration of a Cisco device?
A) show running-config
B) show startup-config
C) copy running-config startup-config
D) show version
Answer: A) show running-config
Explanation
The show running-config command is a fundamental tool used on network devices to display the current active configuration stored in the device’s RAM. This configuration represents the settings and parameters that are currently in effect on the device, including all modifications made since the last time the device was powered on or reloaded. Network administrators rely on show running-config to verify, troubleshoot, and understand the current operational state of a device, such as a router or switch. By viewing the running configuration, administrators can check interface settings, routing protocols, VLAN assignments, access control lists, and other critical parameters that dictate how the device processes traffic and interacts with the network. This makes it an essential command for day-to-day network management and troubleshooting.
When a network administrator executes show running-config, the device outputs a comprehensive list of all commands that are currently active in memory. This includes any configuration changes that have been made during the current session, even if they have not yet been saved to non-volatile storage. Because the running configuration is stored in RAM, it is volatile and will be lost if the device is restarted without saving the configuration. Viewing the running configuration allows administrators to verify that recent changes have been applied correctly and to ensure that the device is operating as intended. It is particularly useful when diagnosing network issues, as it provides a complete snapshot of the device’s active settings, which can be compared with the intended configuration or with configurations on other devices in the network.
In contrast, the show startup-config command displays the configuration that is saved in NVRAM, which is non-volatile memory. This configuration is used when the device boots up to determine its initial settings. While show startup-config is useful for verifying what will be applied on the next reload, it does not include any changes made to the running configuration that have not yet been saved. Therefore, it cannot provide a real-time view of the active configuration and is less useful for immediate troubleshooting or verification of recent changes.
The copy running-config startup-config command serves a different purpose. It saves the current active configuration from RAM to NVRAM, ensuring that changes persist across reboots. While this command is critical for preserving configuration changes, it does not display the configuration itself; instead, it performs the action of storing it for future use. Administrators use this command after verifying the running configuration to prevent the loss of important settings, but it does not replace the need to view the active configuration.
The show version command provides system information, including hardware details, software versions, uptime, and memory usage. While valuable for understanding the device’s general status and capabilities, it does not provide detailed configuration information. It cannot show interface settings, protocol configurations, or other operational parameters, making it insufficient for understanding the current active configuration.
Because the question specifically asks about viewing the active configuration currently in effect on the device, show running-config is the correct command. It provides a complete and real-time view of the device’s operational settings, including all recent changes, which is essential for verification, troubleshooting, and network management. Other commands such as show startup-config, copy running-config startup-config, and show version either display stored configurations, save changes, or provide system information but do not fulfill the requirement of showing the active running configuration.
Question 112
Which protocol provides reliable, connection-oriented communication?
A) TCP
B) UDP
C) ICMP
D) ARP
Answer: A) TCP
Explanation
Transmission Control Protocol, commonly referred to as TCP, is one of the core protocols in the suite of Internet protocols and is designed to provide reliable, connection-oriented communication between devices over a network. TCP ensures that data sent from one device to another is delivered accurately, completely, and in the correct order. It achieves this reliability through several mechanisms, including error checking, sequencing, and acknowledgments. Error checking allows the protocol to detect corrupted data during transmission. Sequencing ensures that even if packets arrive out of order, they can be reassembled correctly at the destination. Acknowledgments confirm the receipt of data, enabling the sender to retransmit any packets that are lost or not successfully delivered. This combination of features makes TCP suitable for applications that require precise and reliable data transfer.
TCP is used by a wide range of critical network applications. For example, HTTP, the protocol used for web browsing, relies on TCP to ensure that web pages are delivered completely and in order. File Transfer Protocol (FTP), used for transferring files between devices, also depends on TCP to guarantee that files arrive without errors and that large files can be broken into smaller packets and reassembled correctly. Email protocols such as SMTP, IMAP, and POP3 similarly use TCP to ensure that messages are transmitted accurately. In all of these cases, the connection-oriented nature of TCP means that a session is established between the sender and receiver before data is transmitted, providing a structured and reliable communication channel.
In contrast, User Datagram Protocol, or UDP, provides connectionless communication. UDP does not establish a session or connection between devices before sending data, and it does not include error checking, sequencing, or acknowledgments. While this makes UDP faster and more efficient for applications that can tolerate some loss, such as streaming audio, video, or online gaming, it cannot guarantee reliable delivery. Packets sent using UDP may be lost, duplicated, or arrive out of order without the protocol automatically correcting these issues. Therefore, UDP is not suitable for applications that require guaranteed and accurate data transmission.
The Internet Control Message Protocol, or ICMP, serves a different purpose entirely. ICMP is used for network diagnostics and error reporting, such as when using the ping command to test connectivity or traceroute to trace the path to a destination. ICMP does not provide transport-layer reliability, sequencing, or error recovery, making it unsuitable for general data transfer that requires accuracy.
The Address Resolution Protocol, or ARP, is used to map IP addresses to physical MAC addresses within a local network. ARP allows devices to deliver packets to the correct hardware address but does not provide any mechanisms for reliable or ordered data delivery.
Because the question specifically asks about reliable, connection-oriented communication, TCP is the correct choice. Its error-checking, sequencing, acknowledgment, and connection-oriented design make it uniquely suited for applications that require accuracy and reliability, distinguishing it from UDP, ICMP, and ARP, which do not provide these guarantees. TCP ensures that data reaches its destination intact, in order, and without loss, making it the cornerstone of dependable network communication.
Question 113
Which command is used to configure a static route on a Cisco router?
A) ip route <destination> <mask> <next-hop>
B) ping <IP>
C) show ip route
D) traceroute
Answer: A) ip route <destination> <mask> <next-hop>
Explanation
The ip route command is a key tool used in networking to configure static routes on routers and Layer 3 devices. Static routing involves manually defining the path that network traffic should take to reach a specific destination. By using the ip route command, administrators can specify the destination network, the subnet mask, and the next-hop IP address or exit interface. This explicit configuration ensures that packets destined for a particular network follow a predetermined path, rather than relying on dynamic routing protocols to calculate the route. Static routes are particularly useful in small networks, for backup paths, or in situations where a fixed, predictable route is required to optimize traffic flow or enhance security.
When a static route is configured using the ip route command, the router adds the route to its routing table. This allows the router to forward packets according to the defined path, bypassing the need to rely on routing protocol calculations. For example, if a network administrator wants all traffic destined for the 192.168.2.0/24 network to be sent via a next-hop router at 192.168.1.2, they would use the ip route command with the appropriate parameters. Once configured, the router will check incoming packets, match the destination network to the static route, and forward the packets to the specified next hop. This method provides predictable routing behavior, which is essential for ensuring reliable communication and meeting specific network design requirements.
Ping, by comparison, is a diagnostic tool used to test connectivity between devices on a network. While it is valuable for verifying that a host is reachable and measuring round-trip time, ping does not alter the routing table or configure paths. It merely sends ICMP echo request packets to a target host and waits for a reply, providing information about connectivity and latency. Because ping does not establish routing rules, it cannot be used to configure static routes.
The show ip route command displays the current routing table on a router or Layer 3 switch. It provides a read-only view of all the routes the device knows, including directly connected networks, static routes, and dynamically learned routes from routing protocols. While show ip route is essential for monitoring and troubleshooting network paths, it does not allow the creation or modification of routes. Administrators can use it to verify that a static route has been successfully added or to examine existing routes, but it does not configure new routing paths.
Traceroute is another network diagnostic tool that identifies the path packets take from a source to a destination. It helps detect routing issues, latency, or network bottlenecks by showing each hop along the path. However, traceroute does not modify the routing table or create static routes; it only observes the existing paths in the network.
Because the question specifically asks about configuring a static route, the ip route command with the destination network, subnet mask, and next-hop IP address is the correct choice. It directly allows administrators to define how traffic is forwarded, providing precise control over network paths. Unlike ping, show ip route, or traceroute, the ip route command actively modifies the routing table, making it the proper tool for static route configuration and ensuring predictable, reliable packet delivery.
Question 114
Which type of VLAN is used for administrative traffic?
A) Management VLAN
B) Voice VLAN
C) Data VLAN
D) Native VLAN
Answer: A) Management VLAN
Explanation
A management VLAN is designed specifically to carry the administrative and control-plane traffic needed for managing network devices. This includes protocols and services such as SSH for secure remote access, Telnet on older or less secure systems, SNMP for monitoring and reporting device status, and other administrative functions. By separating this kind of traffic from regular user traffic, the network ensures that sensitive management communication does not mix with everyday data transmission. This separation greatly enhances security, since administrative access should always be protected and isolated from normal users. It also helps improve the clarity and reliability of network monitoring by ensuring that management information is not obscured or interfered with by common user data.
In contrast, the voice VLAN exists for a completely different purpose. Its role is to transport VoIP traffic generated by IP phones. Voice traffic has strict requirements for latency, jitter, and packet loss, so it is given its own VLAN to allow the network to apply priority queuing and quality-of-service mechanisms. Keeping voice traffic separate from other kinds of communication ensures that phone calls remain clear and uninterrupted, even when the data network is under heavy load.
The data VLAN, on the other hand, is meant for normal user data traffic. This includes activities such as web browsing, file transfers, application usage, and other everyday operations performed by computers, laptops, and other end devices. It is the most common type of VLAN in a typical enterprise environment. While it carries the bulk of network traffic, it does not handle the specialized functions that are assigned to the management or voice VLANs. Keeping user data in its own VLAN helps control broadcast domains, improve performance, and enforce network segmentation.
The native VLAN serves yet another role. On trunk links, which carry traffic for multiple VLANs between switches, the native VLAN is used for untagged frames. Most trunk traffic is tagged so that switches can identify the VLAN of each frame, but certain protocols and situations involve untagged traffic. The native VLAN acts as the default VLAN for these untagged frames. Although it is part of the network structure, it is not intended for management operations or user communication. In fact, best practices advise against using the native VLAN for sensitive or critical traffic due to potential security risks such as VLAN hopping attacks.
Given these distinctions, the correct VLAN for administrative traffic is clearly the management VLAN. This VLAN’s purpose is to provide a secure and isolated channel for device configuration, monitoring, and control. Since the question specifically asks where administrative traffic such as SSH, Telnet, and SNMP should be placed, the management VLAN is the correct and intended answer. It was created specifically for this type of sensitive communication, ensuring that administrators can securely and reliably access network devices without interference or unnecessary exposure to other parts of the network.
Question 115
Which protocol provides one-to-many communication to a subscribed group?
A) Multicast
B) Unicast
C) Broadcast
D) Anycast
Answer: A) Multicast
Explanation
Multicast communication is designed to send packets to multiple devices that have explicitly joined a particular group. This method avoids the inefficiency of sending traffic to every device on a network. Instead, only systems that have expressed interest in the information will receive it. By doing so, multicast reduces unnecessary network congestion and provides a controlled form of one-to-many communication. It is commonly used for applications such as video streaming, online conferencing, and the distribution of real-time data where the same content needs to reach multiple recipients simultaneously without overwhelming network resources.
Unicast, in contrast, represents a straightforward one-to-one communication model. In this model, a single sender communicates directly with a single receiver. Each communication path is unique between the two devices, and separate streams are required if the same information must be sent to multiple receivers. This makes unicast unsuitable for scenarios where many devices need identical data, because the sender would have to produce multiple individual streams, resulting in increased bandwidth consumption. Unicast is best for personalized or private communication such as web browsing, email, or file transfers, where only one intended recipient needs the data.
Broadcast communication differs from both multicast and unicast by sending packets to all devices within the same network segment or subnet. Every device connected to that segment processes the broadcast frames, whether the information is relevant to them or not. While broadcast is useful for functions like device discovery, ARP queries, or certain types of announcements, it is not efficient for delivering information only intended for a subset of devices. Excessive broadcast traffic can degrade network performance by forcing every device on the subnet to pay attention to each broadcast, even when the data is unnecessary for them.
Anycast communication provides a unique one-to-nearest approach. Instead of delivering data to all members of a group, anycast sends packets to the closest device—based on network routing metrics—within a pool of devices offering the same service. This makes anycast useful for load balancing and for improving response times. Common uses include global DNS services, content delivery networks, and geographically distributed servers that want to provide quicker responses by directing clients to the nearest server instance. However, because only one device receives the data, anycast is not a true one-to-many method.
When analyzing the different communication types, it becomes clear that multicast is the correct choice for one-to-many transmission. Unicast cannot achieve one-to-many efficiently because it requires separate streams. Broadcast reaches every device in the subnet instead of a selected group, wasting resources when only some devices need the data. Anycast does not provide one-to-many delivery at all, since only the nearest device receives the packet. Multicast, however, strikes a balance by delivering information to multiple interested receivers without including devices that do not need it. Because the question specifically focuses on one-to-many communication aimed at a particular group of subscribers, multicast is the appropriate and most efficient answer.
Question 116
Which command verifies the IP address assigned to an interface?
A) show ip interface brief
B) show running-config
C) show mac address-table
D) ping
Answer: A) show ip interface brief
Explanation
The command show ip interface brief is widely used on Cisco devices because it provides a clear and efficient of all network interfaces and their assigned IP addresses. This command is especially useful when an administrator needs to quickly verify how interfaces are configured, whether they have the correct IP assignments, and whether they are currently operational. In a single, compact display, the command lists each interface, the IP address associated with it, and two key status indicators: the line status and the protocol status. These status fields help determine whether the interface is physically up and whether the protocol running on that interface is functioning as expected. Because the command presents this information in a simplified table format, it is ideal for troubleshooting, initial device checks, or quick validation after making configuration changes.
In contrast, the show running-config command provides a comprehensive view of the device’s active configuration. While this command is extremely valuable for examining detailed settings, it is not optimized for quickly identifying interface IP addresses. The output includes all configuration elements such as routing settings, VLAN definitions, security features, and interface-specific commands. Finding IP addresses within this lengthy output requires scrolling through multiple lines of text and manually locating each interface’s configuration. Although show running-config is essential for in-depth troubleshooting and auditing, it does not offer the concise, easy-to-read that the question is asking for.
Meanwhile, the show mac address-table command serves an entirely different purpose. Its focus is on listing MAC addresses that the switch has learned and the ports on which those MAC addresses have been detected. This command is primarily used for diagnosing issues related to Layer 2 switching, such as verifying where a device is connected, checking for proper MAC learning behavior, or identifying switching loops. Because it operates at Layer 2 and deals only with MAC addresses and switch ports, it does not display any IP addresses or provide information about interface IP configuration. Therefore, it is not relevant for verifying IP address assignments.
Another commonly used tool, ping, tests network connectivity by sending ICMP echo requests to a specified destination. While ping is very effective for determining whether a device is reachable and whether there are latency or packet loss issues, it does not provide any information about the local device’s interface IP addresses. It simply confirms whether the chosen destination responds. Administrators use ping frequently during troubleshooting, but it is not designed for examining interface configurations.
Given these comparisons, the correct command for verifying IP addresses assigned to interfaces is show ip interface brief. It is the most efficient and direct method, offering a quick overview of all interfaces, their IP assignments, and their operational status in a single output. This makes it the ideal choice when the question specifically requires checking which IP addresses are configured on each interface.
Question 117
Which type of IPv4 address allows communication with a specific group of hosts?
A) Multicast
B) Unicast
C) Broadcast
D) Anycast
Answer: A) Multicast
Explanation
Multicast addresses are used for one-to-many communication to devices that have joined a specific multicast group, efficiently sending data to multiple subscribers.
Unicast addresses communicate with a single device.
Broadcast addresses send data to all devices in a subnet.
Anycast addresses send data to the nearest device among a group sharing the same address.
Because the question specifies communication with a group of hosts, Multicast is correct.
Question 118
Which command displays all connected neighbors discovered using CDP?
A) show cdp neighbors
B) show interfaces
C) show ip route
D) ping
Answer: A) show cdp neighbors
Explanation
Show cdp neighbors lists all directly connected Cisco devices discovered via Cisco Discovery Protocol (CDP), providing device ID, local interface, and port ID.
Show interfaces displays interface status and statistics but not neighbor information.
Show ip route displays routing table information.
Ping tests connectivity to a specific host but does not discover neighbors.
Because the question asks for connected neighbors using CDP, show cdp neighbors is correct.
Question 119
Which VLAN type carries untagged traffic on a trunk port?
A) Native VLAN
B) Access VLAN
C) Management VLAN
D) Voice VLAN
Answer: A) Native VLAN
Explanation
Native VLAN is assigned on trunk ports to handle untagged traffic. Frames sent on this VLAN are not tagged with 802.1Q headers.
Access VLAN is assigned to an access port for a single VLAN.
Management VLAN is for device administrative traffic.
Voice VLAN is for IP phone traffic with QoS prioritization.
Because the question specifies untagged traffic on a trunk, Native VLAN is correct.
Question 120
Which command displays all the IP addresses learned through DHCP?
A) show ip dhcp binding
B) show ip interface brief
C) show running-config
D) show mac address-table
Answer: A) show ip dhcp binding
Explanation
Show ip dhcp binding displays all IP addresses leased to clients, along with MAC addresses, lease expiration, and associated VLAN or interface.
Show ip interface brief shows interface IPs and status but not DHCP bindings.
Show running-config displays the active configuration but not lease information.
Show mac address-table shows learned MAC addresses on switch ports.
Because the question asks for DHCP-learned addresses, show ip dhcp binding is correct.