This scenario describes the classic router-on-a-stick inter-VLAN routing design. A single physical interface on R1 connects to switch S1, and multiple sub-interfaces are created on that physical interface to serve as gateways for multiple VLANs. Therefore, if R1 provides Layer 3 gateway functions for VLAN 2 and VLAN 3, sub-interfaces such as GE0/0/1.2 and GE0/0/1.3 must be configured, so option A is correct.

Because PC2 and PC3 are connected to switch S1, S1 learns their source MAC addresses dynamically and stores them in its MAC address table, making option B correct. R1 receives tagged frames from different VLANs on the trunk link and, through its sub-interfaces, can identify and terminate frames for VLAN 2 and VLAN 3, so option C is also correct. Option D is incorrect because hosts in different VLANs do not need to be connected to different physical switches; VLAN separation is logical, not necessarily physical. HCIA-Datacom uses this deployment to explain inter-VLAN communication, 802.1Q trunking, and flexible campus gateway design using limited router interfaces.

The exhibit shows GE1/0/2 as an access port in VLAN 3 on both switches, so PC2 and PC4 belong to the same Layer 2 broadcast domain. The inter-switch GE1/0/3 link is a trunk that permits VLANs 2 and 3, allowing VLAN 3 frames to pass between SW1 and SW2. Therefore, PC2 and PC4 can communicate at Layer 2, making statement B true. GE1/0/1 remains an access interface in the default VLAN 1 because no other default VLAN is configured. VLAN 1 is not permitted across the shown trunk, so PC1 cannot communicate with PC3 across the switches. PC1 and PC2 are also in different VLANs locally, and PC2 and PC3 are in different VLANs. Devices in different VLANs cannot exchange Layer 2 traffic directly; a Layer 3 gateway is required for inter-VLAN communication. Accordingly, statements A, C, and D are the false statements, which makes A, C, and D the correct selections.

In STP, the root bridge has all its active ports elected as designated ports on each connected segment. On non-root switches, one port is selected as the root port , and on each LAN segment, one designated port is elected based on the best BPDU. Since SW1 is the root bridge and all links have equal cost, the election depends first on the path cost to the root, then on bridge ID, and then on port ID if needed.

According to the topology, the ports that become designated are GE1/0/2 of SW2 , GE1/0/1 of SW2 , and GE1/0/3 of SW3 , which correspond to option A , B , and C . Option D is not a designated port in this topology because that segment has another port with a superior BPDU and therefore SW4’s port does not win the designated-port election. HCIA-Datacom emphasizes that designated ports are elected per segment , not per switch, and that every non-root switch must compare received BPDUs to determine root and designated roles. This question tests the ability to apply STP election logic rather than simply memorizing port-role definitions.

The acronym in the source file is mistyped as PCF. The correct intelligent lossless Ethernet technology is PFC, which stands for Priority-based Flow Control. PFC extends Ethernet flow control by applying pause behavior to selected traffic priorities rather than stopping all traffic on an interface. When a downstream device detects that a lossless priority queue is approaching congestion, it can send a priority-specific pause indication to the upstream sender. The upstream device temporarily stops transmitting traffic for that priority, preventing the downstream buffer from overflowing and thereby supporting zero-packet-loss behavior for the protected traffic class. This capability is important in intelligent computing and data center fabrics carrying storage or high-performance computing workloads that are sensitive to packet loss. Huawei describes PFC as a foundational technology for intelligent lossless networks, often used together with congestion-management mechanisms such as ECN and related optimization features. Therefore, the blank must be filled with PFC in uppercase. The original answer PCF should be corrected to PFC.

According to the original topology and service-planning question, the required VLANs are VLAN 100 , VLAN 101 , and VLAN 102 , so options A , B , and C are correct. In HCIA-Datacom campus design questions, VLAN planning is usually based on service separation, such as user services, voice services, wireless services, management services, or specific departmental segmentation. Each service type is assigned an appropriate VLAN so that broadcast domains are separated and policies can be applied more effectively.

The reason option D is not selected is that it does not match the service requirements shown in the original figure. VLAN planning must follow the actual service design rather than arbitrary numbering. HCIA-Datacom emphasizes that campus VLAN planning should align with traffic isolation, gateway design, security policy deployment, and future scalability. Proper VLAN assignment helps simplify troubleshooting, reduce unnecessary broadcasts, and support service-based policy enforcement. This question tests the ability to read a service topology and identify which VLANs are actually required by the depicted design rather than choosing extra VLANs that are not part of the planned campus solution.

Duplicate Address Detection ( DAD ) is an IPv6 mechanism used to verify that a unicast address is not already in use before the address is assigned to an interface. DAD is implemented using Neighbor Solicitation (NS) and Neighbor Advertisement (NA) messages, which are part of the ICMPv6 Neighbor Discovery protocol. Therefore, options A and D are correct.

When a host wants to verify a tentative IPv6 address, it sends an NS message for that address. If another node on the link is already using that address, that node responds with an NA message, indicating the address is duplicated and cannot be assigned. If no NA is received within the required period, the host assumes the address is unique and can use it. Options B and C are incorrect because Router Solicitation (RS) and Router Advertisement (RA) are used for router discovery, prefix advertisement, and stateless address autoconfiguration, not for DAD itself. HCIA-Datacom emphasizes the distinction between Neighbor Discovery functions, including address resolution, next-hop reachability, router discovery, and duplicate address detection in IPv6 networks.

Huawei uses DHCP Option 148 for IPv4-based plug-and-play or zero-touch deployment of devices to iMaster NCE-Campus. The DHCP server can include controller information in this vendor-specific option, allowing a switch, router, or cloud-managed AP to obtain the southbound address or URL of iMaster NCE-Campus together with the required management port. After the device receives normal addressing information and the Option 148 parameters, it can reach the controller and establish the management channel, including NETCONF-based management in supported deployment scenarios. Huawei documentation distinguishes this from IPv6 deployment, where Option 17 can be used for equivalent controller discovery. The Option 148 value commonly carries fields such as the controller management mode, domain or IP address, and management port. This removes the need to manually enter controller information on every new device and is widely used in iMaster NCE- Campus onboarding workflows. Therefore, the numeric value required in the blank is 148, matching the source answer and Huawei campus deployment documentation.

Wi-Fi 7 supports operation in the 2.4 GHz , 5 GHz , and 6 GHz frequency bands, so options A , C , and D are correct. These three bands together provide flexible coverage and capacity options. The 2.4 GHz band offers better propagation and wider coverage, while the 5 GHz and 6 GHz bands provide more channels, higher capacity, and better support for high-speed, low-latency services.

Option B , 9.6 GHz , is incorrect because it is not a Wi-Fi 7 operating band. HCIA-Datacom WLAN content highlights Wi-Fi 7 as a major advancement in wireless performance, bringing improvements in throughput, channel usage, spectrum efficiency, and latency characteristics. The addition and use of the 6 GHz band is especially important because it expands available spectrum resources and helps reduce contention in dense wireless environments. In practical enterprise WLAN design, understanding supported frequency bands is essential for channel planning, interference control, device compatibility assessment, and service optimization. This question checks whether the learner can correctly identify the standard operating bands used by modern Wi-Fi 7 networks.

All four statements are correct. The code uses the Paramiko library to automate SSH login to a network device. import paramiko and import time load the Python modules required for SSH communication and delay control, so option C is correct. The statement ssh = paramiko.SSHClient() creates an SSH client object, and ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy()) allows the client to accept an unknown host key automatically in this example scenario.

The command ssh.connect( ' 192.168.1.254 ' , username= ' python ' , password= ' Huawei@123 ' ) establishes an SSH connection to the target device, so option B is correct. Then channel = ssh.invoke_shell() opens an interactive shell channel , which is commonly used to send CLI commands and receive output just as an administrator would in a terminal session, making option D correct. The command channel.send( ' screen-length 0 temporary\n ' ) disables page-by-page output for the current session, which is useful in network automation. Finally, ssh.close() closes the SSH session and releases the connection, so option A is correct. HCIA-Datacom automation knowledge often uses Paramiko examples to demonstrate basic Python-based device O & M.

LACP mode and manual load-balancing mode behave differently when an Eth-Trunk contains a link connected to the wrong peer. In LACP mode, member interfaces exchange LACPDUs and the switches determine which physical links can participate in the same aggregation. GE1/0/1 through GE1/0/3 are correctly connected between SW1 and SW2, so they can form an operational LACP Eth-Trunk. GE1/0/4 is connected to SW3 and cannot successfully negotiate as a member of the SW1-SW2 LAG; it is therefore not used for service forwarding to SW3. This makes A and B true. In manual mode, there is no LACP negotiation to validate that every member terminates on the same peer. If GE1/0/4 is manually placed in the trunk, the device may treat it as a forwarding member and hash some traffic onto that link toward SW3. The trunk does not automatically go Down solely because of that incorrect peer connection. Therefore C is false and D is true.

On a non-root bridge, the root port is the port that receives the best BPDU toward the root bridge. STP selects the root port by comparing several parameters in order. The first important parameter is the root path cost (RPC) , so option B is correct. If multiple ports have the same RPC, the switch then compares the bridge ID (BID) of the upstream device sending the BPDU, making option C correct. If those are still equal, the switch compares the port ID (PID) of the upstream sending port, so option D is also correct.

If all of those values remain identical from the switch’s perspective, the device can finally compare the local port ID to determine which local interface becomes the root port, so option A is also correct. HCIA-Datacom teaches this comparison logic as part of STP election rules. The process ensures deterministic selection of a single root port on every non-root switch. Understanding the comparison sequence is essential for predicting STP topology behavior and for influencing port roles through path cost tuning or bridge-priority adjustments during campus network design and troubleshooting.

This question tests the difference between Layer 3 addressing and Layer 2 encapsulation during routing. The IP packet originated by PC1 keeps PC1 ' s IP address as its source IP and PC2 ' s IP address as its destination IP as it traverses the routers. Ethernet MAC addresses, however, are rewritten at every routed hop. When R1 forwards the packet across the link toward R2, R1 builds a new Ethernet frame on its outgoing interface. According to the exhibit, R1 ' s outgoing interface on the R1-R2 link uses MAC_C, so MAC_C is the source MAC address. The next-hop device on that link is R2, whose receiving interface uses MAC_D, so MAC_D is the destination MAC address. MAC_A belongs to PC1 and was relevant only on the first local Ethernet segment. MAC_F belongs to PC2 and is used on the final Ethernet segment from R2 to PC2, not on the R1-R2 link. Therefore the correct statements are B and D. The uploaded key B, C is incorrect.

The destination address FF-FF-FF-FF-FF-FF is the Ethernet broadcast address. A switch floods a broadcast frame through the other eligible ports in the same VLAN, so both Host B and Host C can receive the frame. Option C, 53-80-C2-00-00-01, is a multicast MAC address because the individual/group bit, which is the least significant bit of the first octet, is 1. The first octet 0x53 has a binary least significant bit of 1, identifying a group address. Multicast frames may therefore be delivered to multiple receivers in the same Layer 2 domain, depending on multicast handling and membership behavior. By contrast, the first octets in options B and D, 0x98 and 0x34, have a least significant bit of 0 and are unicast addresses. A unicast frame is intended for a single MAC destination and is not normally delivered simultaneously to both hosts. Therefore A and C are the correct choices. This classification is fundamental when predicting whether a switched Ethernet frame is delivered to one station or replicated to multiple receivers simultaneously.