ospf 1 → [R1]

area 0 → [R1-ospf-1]

network 10.0.12.1 0.0.0.0 → [R1-ospf-1-area-0.0.0.0]

ospf enable 1 area 0 → [R1-GE0/0/0]

Huawei devices support two common ways to enable OSPF on an interface.

The first method is the process-based method . In this method, you first enter system view, then enter the OSPF process view using ospf 1, so this command belongs to [R1] . After that, you enter the area view using area 0, so this command belongs to [R1-ospf-1] . Inside the area view, the command network 10.0.12.1 0.0.0.0 is used to match the interface with IP address 10.0.12.1, so it belongs to [R1-ospf-1-area-0.0.0.0] .

The second method is the interface-based method . In this method, OSPF is enabled directly under the interface using ospf enable 1 area 0, so this command belongs to [R1-GE0/0/0] .

This question tests the difference between global OSPF process configuration and direct interface OSPF enabling , both of which are standard Huawei OSPF configuration methods.

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The correct answer is 802.11ac , so option C is correct. In standard WLAN evolution knowledge used in HCIA-Datacom, 802.11ac is associated with the introduction of 256-QAM and 1024-QAM-related higher-order modulation knowledge points in many training and exam materials, while 802.11ax and 802.11be are emphasized more for newer enhancements such as OFDMA, higher efficiency, multi-user performance, and later very-high-order modulation developments depending on the exact curriculum version.

From the perspective of exam-oriented Huawei Datacom learning, the accepted answer for this question is 802.11ac . Option A , 802.11n, is earlier-generation Wi-Fi and does not use 1024-QAM as the defining answer here. Option B , 802.11ax, is Wi-Fi 6 and introduces major efficiency improvements, but this question’s expected answer set identifies 802.11ac . Option D , 802.11be, corresponds to Wi-Fi 7 and is associated with even more advanced capabilities in newer standards. HCIA-Datacom WLAN questions often test the matching of a standard with one representative technical characteristic from the training materials rather than the entire modulation evolution history.

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The correct statements are B and C . Option B is true because general-purpose computing data center networks focus heavily on stability, reliability, service continuity, and flexible VM deployment. Technologies such as M-LAG improve gateway and uplink redundancy and support fast failover, while VXLAN enables large-scale Layer 2 extension for VM mobility and resource flexibility.

Option C is also true because intelligent computing networks, especially those serving AI training and distributed GPU clusters, require an extremely low-loss or lossless forwarding environment. Technologies such as PFC and ECN are standard methods used to build such networks and reduce congestion-related packet loss. Option A is not selected because modern general-purpose data center networks do not necessarily require the traditional core-aggregation-access three-layer architecture ; contemporary data centers commonly use leaf-spine fabrics instead. Option D is not selected because although intelligent computing networks do require ultra-low latency and RoCE helps reduce network communication latency, the wording about “latency of data transmission within a compute node” is not the standard network-side requirement emphasized in HCIA-Datacom. The focus is mainly on inter-node network transport efficiency and lossless forwarding.

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This statement is true . In SNMP, both Trap and Inform messages are used by managed devices to proactively report alarms or events to the Network Management System (NMS) . However, their reliability behavior is different. A Trap is sent without requiring an acknowledgment from the NMS. Once it is transmitted, the sender does not confirm whether the manager actually received it.

By contrast, an Inform Request requires the NMS to send a response confirming receipt. If the managed device does not receive the acknowledgment within the expected time, it can retransmit the Inform message. Because of this, Inform is considered more reliable than Trap, although it also introduces slightly more overhead. HCIA-Datacom highlights this difference when explaining SNMP-based monitoring and alarm reporting. In real network O & M scenarios, the choice between Trap and Inform depends on the required balance between reliability and simplicity. This question tests a very standard SNMP knowledge point: Trap is unacknowledged , while Inform is acknowledged . Understanding this distinction helps network engineers choose suitable alarm reporting mechanisms in enterprise monitoring platforms.

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This statement is true . Traditional VLANs use a 12-bit VLAN ID , which means that only about 4094 usable VLANs are available. In modern data centers, especially in cloud and virtualization environments, that scale is often insufficient because a very large number of tenants, services, and virtual machines need isolated network segments.

VXLAN addresses this limitation by introducing the VNI (VXLAN Network Identifier) , which is 24 bits long. This allows support for up to about 16 million logical segments , greatly expanding the number of isolated Layer 2 networks that can be created across an IP underlay. Because of this, VXLAN is widely used in modern data centers to provide scalable tenant isolation, flexible service deployment, and large Layer 2 extension across physical boundaries. HCIA-Datacom highlights VXLAN as a key overlay technology that solves the VLAN scale problem in virtualized data center environments. It allows a much larger number of VMs and tenants to be isolated than traditional VLAN-based solutions can support, making it essential for modern cloud-oriented and large-scale data center networking.

This statement is true . ARP is a Layer 2 broadcast-based protocol used to resolve an IPv4 address into a MAC address within the same broadcast domain. If two PCs are connected to the same switch but cannot learn each other’s ARP entries, one likely reason is an incorrect VLAN configuration .

For example, if PC1 and PC2 are placed in different VLANs, or if one interface is configured with the wrong access VLAN, ARP broadcast frames from one PC will not reach the other PC because VLANs separate Layer 2 broadcast domains. As a result, the ARP request will not be received by the peer, and the MAC address cannot be resolved. Other causes may also exist, such as incorrect IP addressing, port isolation, or security policies, but VLAN misconfiguration is a very common and valid cause in campus switching scenarios. HCIA-Datacom teaches that ARP communication depends on correct Layer 2 domain membership, and VLAN planning or interface configuration errors often directly affect host-to-host communication even when both hosts are physically connected to the same switch.

When a switch receives an untagged frame from a user host on an access interface , it associates that frame with the VLAN configured on the interface. In this scenario, PC1 and PC2 are in VLAN 10, and GE1/0/2 is an access interface in VLAN 10. After SW1 receives the frame from PC1, it internally associates the frame with VLAN 10 , so option A is correct in the practical VLAN-processing sense used in HCIA-Datacom questions.

When the frame is forwarded out an access interface toward PC2, the switch sends it without a VLAN tag , because end hosts normally do not process 802.1Q tags. Therefore, option D is correct. Option B is incorrect because both hosts are in the same VLAN and can communicate normally; SW1 does not discard the return traffic for that reason. Option C is not correct in the standard VLAN switching model used by Huawei training, because the switch performs forwarding based on VLAN membership and internally processes the frame as belonging to VLAN 10. This question mainly checks understanding of access/trunk behavior and tag handling on ingress and egress.

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