H12-351_V1.0 HCIE-WLAN (Written) V1.0 Question and Answers

Radio calibration is applicable to high-density scenarios where a large number of users access the network simultaneously and require high bandwidth, such as stadiums, exhibition halls, and conference centers. Radio calibration can improve user experience by increasing the frequency bandwidth for high-load APs.

In a dual-link backup scenario, when the active link recovers, the AP waits for 15 Echo intervals before switching back to the original primary WAC. This prevents frequent link switchovers caused by unstable links.

According to the Huawei documents and resources, the VRRP preemption delay is the time that an AC waits before preempting another AC with a lower priority. If the VRRP preemption delay is set to a small value, the following problems may occur after a master/backup switchover:

B. A master/backup switchback is triggered too quickly. If the master AC recovers soon after a switchover, it may preempt the backup AC again and become the master AC.  This may cause frequent switchovers and affect network stability 1 .

C. Backup information is incomplete. If the backup AC takes over services from the master AC too quickly, it may not have received all the data sy nchronized from the master AC through HSB.  This may cause service interruption or data loss 2 .

Therefore, B and C are the correct answers. References:  1 : https://support.huawei.com/enterprise/en /doc/EDOC1100064368/80fc2ebd/example-for-configuring-vrrp-hsb  2 : https://support.huawei.com/enterprise/en/doc/EDOC1100096325/1a753937/vrr p-hsb-configuration

According to the Huawei documents and resources, the definitions of the short-range wireless IoT technologies are as follows:

ZigBee: IEEE 802.15.4-based wireless communication technology is a short-range, and low-power wireless communication technology that supports star, mesh, and hybrid networking.

Bluetooth: With the emergence of IoT industries such as smart wearables, smart home, and Internet of Vehicles, short-range communication technologies are attracting more and more developers.

REID: Its basic principle is to automatically identify objects based on the transmission characteristics of radio signals and space coupling (inductance or electromagnetic coupling) or radar reflection.

Wi-Fi: Wireless networking technology based on IEEE 802.11 is the most popular WLAN technology.

Therefore, ZigBee - 1, Bluetooth - 3, REID - 2, Wi-Fi - 4 is the correct answer. References: : https://support.huawei.com/enterprise/en/doc/EDOC1100158948/9a0d5c37/zigbee : https://support.huawei.com/enterprise/en/doc/EDOC1100158948/9a0d5c37/bluetooth : https://support.huawei.com/enterprise/en/doc/EDOC1100158948/9a0d5c37/rfid : https://support.huawei.com/enterprise/en/doc/EDOC1100158948/9a0d5c37/wi-fi

B is false because only Layer 3 VXLAN gateways need to maintain VBDIF interfaces for inter-subnet communication on a VXLAN network or communication with external non-VXLAN networks. Layer 2 VXLAN gateways do not need VBDIF interfaces.

According to the Huawei documents and resources, EAP termination and EAP relay are typical 802.1X authentication modes between the access device and authenticatio n server. In EAP termination mode, the access device terminates EAP packets and encapsulates them into RADIUS packets.  In EAP relay mode, the access device directly encapsulates t he received EAP packets into RADIUS using EAP over RADIUS (EAPoR) packets 2 .  Therefore, A and B are the correct answers. References:  2 : https://support.huawei.com/enterprise/en/doc/EDOC1100086527

The home agent is a device that communicates with the gateway on the STAs’ home network at Layer 3 and maintains the binding entries of STAs’ home addresses and care-of addresses. A home WAC can function as a home agent of STAs, while a home AP cannot.

Fingerprint-based positioning technology is a method that uses the signal strength or phase difference of wireless signals to locate objects. There are two types of fingerprint-based positioning technology: virtual fingerprint-based positioning and real fingerprint-based positioning. In virtual fingerprint-based positioning, the positioning engine generates a virtual fingerprint library through calculations based on the AP deployment and environment information. In real fingerprint-based positioning, the fingerprint map is obtained through onsite information collection.

In DHCPv6 stateful autoconfiguration, a client obtains an IPv6 address, a PD prefix (if required), and other configuration parameters (such as DNS server address) from a DHCPv6 server.

C is false because the license file only affects the number of devices that can be managed by iMaster NCE-CampusInsight, not the data display.

E is false because the UTC time of devices does not need to be consistent with that of iMaster NCE-CampusInsight.

The WPA3 transition mode applies to both WPA3-Enterprise and WPA3-Personal. In this mode, WPA3 and WPA2 can coexist for a period of time in the future to enable WPA3-incapable STAs to access a WPA3-configured network.

Broadcast address is not an IPv6 address type. IPv6 does not support broadcast addressing, but uses multicast addressing instead. The other options are valid IPv6 address types. Unicast address identifies a single interface, multicast address identifies a group of interfaces, and anycast address identifies multiple interfaces but delivers packets to only one of them.

BSS coloring is a feature introduced in Wi-Fi 6 that assigns different colors to different BSSs to reduce co-channel interference. BSS coloring provides the following advantages:

Higher packet rate on the air interface: BSS coloring reduces collisions between packets from different BSSs on the same channel, improving packet transmission efficiency.

More efficient channel use: BSS coloring allows spatial reuse of channels by different BSSs, increasing channel utilization.

Higher concurrency in high-density scenarios: BSS coloring reduces interference among neighboring APs and improves network performance in high-density scenarios.

MP: Mesh node that uses IEEE 802.11 MAC and PHY protocols for wireless communication. This node supports automatic topology discovery, automatic route discovery, and data packet forwarding.  It can provide both mesh service and user access service 1 .

MPP: MP node that connects a WMN to MPs on other types of networks.  This node can function as a portal for communication between internal mesh nodes and external networks 1 .

Neighbor MP: Neighboring MP with which an MP prepares to establish a mesh link 1 .

Candidate MP: AP that directly communicates with a mesh node 2 .

https://support.huawei.com/enterprise/en/doc/EDOC1100064365/90f2391e/configuration-examples-for-mesh  2 : https://support.huawei.com/enterprise/en/doc/EDOC1100169459/8d79210e/configuring-wireless-mesh-networking

B is false because calculated data can be displayed on iMaster NCE-CampusInsight without loading a license on the device management page. The license only affects the number of devices that can be managed by iMaster NCE-CampusInsight.

D is false because the UTC time of iMaster NCE-CampusInsight does not need to be the same as that of its managed devices. However, it is recommended that they use the same time zone to avoid confusion.

ATP stands for Acceptance Test Plan, which is a document that needs to be output after the low level design is complete. The ATP describes the acceptance criteria and test cases for the project.

The load percentage of an AP is calculated by dividing the number of associated STAs by the maximum number of STAs supported by the AP. In this case, the load percentage of AP_1 is 4/10 = 40%, and that of AP_2 is 1/10 = 10%. The load balancing mechanism needs to be enabled to balance the load between AP_1 and AP_2. Then some STAs are steered from AP_1 to AP_2 based on the load balancing threshold and the load difference threshold.

A router is not included in a typical RFID system. A typical RFID system consists of three components: RFID tag, RFID reader, and information processing platform. The RFID tag is attached to the object to be identified, the RFID reader communicates with the tag and reads its information, and the information processing platform processes and stores the data collected by the reader.

A. In EAP termination mode, an access device encapsulates EAP packets sent by an 802. IX client Into RADIUS packets, without processing the data in the EAP packets.  This statement is false because in EAP termination mode, an access device extracts informat ion from EAP packets, encapsulates the information into RADIUS packets, and sends the RADIUS packets to an authentication server 2 .

D. The EAP termination mode simplifies the proce ssing on an access device and supports various authentication methods. However, this mode requires an authentication server to support EAP and have high processing capability.  Thi s statement is false because it describes the EAP relay mode, not the EAP termination mode 2 .

Therefore , A and D are the correct answers. References:  2 : https://support.huawei.com/enterprise/en/doc/EDOC1100086527