HPE3-U01 Aruba Certified Network Technician Exam (ACNT) Questions and Answers

To establish a secure web connection to YouTube.com, the computer will run two protocols: DNS and HTTPS. DNS (Domain Name System) is a protocol that translates domain names into IP addresses, which are used to identify and locate web servers on the internet. HTTPS (Hypertext Transfer Protocol Secure) is a protocol that encrypts and authenticates data transfer between a web browser and a web server, ensuring the security and integrity of the communication.

The computer does not need to run DHCP (Dynamic Host Configuration Protocol), FTP (File Transfer Protocol), or HTTP5 (a non-existent protocol) to connect to YouTube.com. DHCP is a protocol that assigns IP addresses to devices on a network automatically, but the computer already has a static address configured. FTP is a protocol that transfers files between a client and a server, but it is not used for web browsing. HTTP5 is not a valid protocol name, and it is likely a typo for HTTP (Hypertext Transfer Protocol), which is the unsecure version of HTTPS. References:

• Aruba Certified Network Technician (ACNT) | HPE Aruba Networking
• 6 Network Security Protocols You Should Know | Cato Networks
• What is HTTPS? | Cloudflare

To configure interfaces 1/1/1 and 1/1/2 as VLAN 10 access ports in ArubaOS-CX switches, the following commands are required:

switch(config)# vlan 10

switch(config-vlan-10)# name VLAN10

switch(config-vlan-10)# exit

switch(config)# interface 1/1/1

switch(config-if)# no shutdown

switch(config-if)# vlan access 10

switch(config-if)# exit

switch(config)# interface 1/1/2

switch(config-if)# no shutdown

switch(config-if)# vlan access 10

switch(config-if)# exit

Option B shows the correct syntax and sequence of commands to create VLAN 10, assign a name to it, and configure the interfaces as access ports in that VLAN. Option A is incorrect because it uses the wrong keyword vlan-id instead of vlan access. Option C is incorrect because it does not create VLAN 10 before assigning the interfaces to it. Option D is incorrect because it uses the wrong keyword vlan mode instead of vlan access. References: ArubaOS-CX 10.05 Fundamentals Guide 6200 Switch Series, Configuring VLANs on AOS-CX - Aruba

 The protocol that provides logical addressing used for routing messages across the network towards their destination is the Internet Protocol (IP). IP is a network layer protocol that assigns a unique numerical identifier to each device on a network, called an IP address. IP addresses are used to identify the source and destination of data packets, and to determine the best path to deliver them. IP is a connectionless and best-effort protocol, meaning that it does not guarantee the delivery, order, or integrity of the packets. IP relies on other protocols, such as TCP, to provide reliable and orderly data transfer.

The other options are incorrect because:

B. Transmission Control Protocol (TCP) is a transport layer protocol that provides reliable and orderly data delivery by establishing a connection between devices and providing error-checking and retransmission mechanisms. TCP does not provide logical addressing or routing functions, but it uses IP addresses to identify the endpoints of a connection.

C. Wired Ethernet is a data link layer protocol that defines the physical and logical characteristics of a wired network, such as cable types, frame formats, and MAC addresses. MAC addresses are used to identify the physical devices on a network segment, but they are not used for routing messages across the network. Ethernet does not provide logical addressing or routing functions, but it relies on IP to do so.

D. Link Layer Discovery Protocol (LLDP) is a data link layer protocol that allows devices to discover and advertise information about themselves and their neighbors on a network, such as device type, capabilities, port configuration, and VLAN membership. LLDP does not provide logical addressing or routing functions, but it can help network administrators to troubleshoot and optimize the network topology. References:

• Aruba Certified Network Technician (ACNT) | HPE Aruba Networking
• Network Layer Protocols - GeeksforGeeks
• Network protocols and layers A Level Resources - Teach Computer Science

Role Based controls are a feature of Aruba Central that allows you to assign different access privileges and policies to different groups of users on a WLAN network. You can set the Role Based controls in the Security section of the Aruba Central WLAN configuration Wizard. In this section, you can configure the following parameters:

• Authentication Type: The method of verifying the identity of users who connect to the WLAN network. You can choose from several options, such as WPA2-Enterprise, WPA2-Personal, Captive Portal, MAC Authentication, or Open.
• Authentication Server: The server that performs the authentication process for the users. You can select an existing server from the list, or create a new one by clicking the + icon. You can also configure the server settings, such as IP address, port, shared secret, and timeout.
• User Role Assignment: The method of assigning user roles to the authenticated users. You can choose from several options, such as Default Role, Role Derivation, or Server Group Role. A user role is a set of firewall policies and VLAN settings that define the access privileges and restrictions for a group of users.
• Default User Role: The user role that is assigned to the users by default, if no other role assignment method is selected. You can select an existing user role from the list, or create a new one by clicking the + icon. You can also configure the user role settings, such as firewall policies, VLAN ID, and bandwidth limit.

References:

• Configuring Security Settings for Wireless Network
• Basic WLAN Configuration Workflow

A hardwire desktop PC belongs to the category of stationary devices, which are devices that are fixed in one location and do not move. Stationary devices typically have a constant power supply and a wired network connection. Examples of stationary devices are desktop PCs, servers, printers, and IP phones. Stationary devices are different from mobile devices, which are devices that can move from one location to another and connect to the network wirelessly. Mobile devices can be further classified into somewhat mobile devices, highly mobile devices, and intermittent mobile devices, depending on their mobility patterns and network requirements. Examples of mobile devices are laptops, tablets, smartphones, and wearable devices. References:

• Aruba Certified Network Technician (ACNT) | HPE Aruba Networking
• Aruba Documentation Portal

The Wi-Fi Alliance is an organization that promotes interoperability among WLAN device manufacturers. The Wi-Fi Alliance is an important organization for the advancement of wireless LAN (WLAN) technology. It develops certification programs and technologies that deliver quality Wi-Fi experiences. Members have completed more than 80,000 certifications. Through industry-developed comprehensive testing, Wi-Fi Alliance certification programs ensure that Wi-Fi products from multiple manufacturers work well together. These certification programs are foundational to the rapid adoption and proliferation of Wi-Fi products in home, office, and public access locations around the world and underpin the success of Wi-Fi technology proliferation. Only Wi-Fi CERTIFIED™ products have been tested to deliver interoperability with the latest technologies, and industry-standard security protections. The Wi-Fi CERTIFIED logo gives consumersconfidence that the Wi-Fi devices purchased deliver a positive user experience, regardless of brand. For retailers, vendors, and service providers, the Wi-Fi CERTIFIED seal of approval means consistent performance and better user experience. A company must be a member of Wi-Fi Alliance ® and achieve certification to use the Wi-Fi CERTIFIED logo and Wi-Fi CERTIFIED certification marks. The Wi-Fi Alliance certification programs cover the following categories: Connectivity, Security, Mobility, Coexistence, and Performance123. References: Certification | Wi-Fi Alliance, Programs | Wi-Fi Alliance, Aruba Certified Network Technician Exam HPE3-U01 Actual Questions, Why Wi-Fi Certification Really Matters | Aruba Blogs

 The 5 GHz band is a radio frequency band used for Wi-Fi communications. It has a higherdata bandwidth than the 2.4 GHz band, but a shorter range and less penetration through walls. The 5 GHz band is divided into several sub-bands, each with a different set of channels. One of these sub-bands is the U-NII-3 band, which covers the frequency range from 5725 MHz to 5850 MHz. This sub-band contains 24 non-overlapping channels, numbered from 149 to 172. Channels 149 to 161 are part of the 5 GHz band and can be used for Wi-Fi communications. Channels 165 and 169 are restricted to indoor use only, and channel 173 is not allowed in some regions. Channels 12, 13, and 14 are not part of the 5 GHz band, but belong to the 2.4 GHz band, which has a different set of channels and regulations. U-NII-5 is not a valid sub-band name, but a proposed extension of the 5 GHz band to include the frequency range from 5925 MHz to 7125 MHz. This extension is not yet approved or implemented, and therefore not part of the 5 GHz band. References: List of WLAN channels, What’s the Difference Between 2.4 and 5 GHz Wi-Fi (and Which Should I Use)?, What is the difference between 2.4 GHz, 5 GHz, and 6 GHz wireless frequencies?

 The dual-band IEEE WLAN standard that provides up to 4.8 Gbps of theoretical data rate is 802.11 be, also known as Wi-Fi 7. This standard is an amendment to the IEEE 802.11-2020 standard that aims to improve the performance, efficiency, and reliability of WLANs operating in the 2.4 GHz and 5 GHz frequency bands. Some of the key features of 802.11 be include:

• Enhanced multi-user multiple-input multiple-output (MU-MIMO) that supports up to 16 spatial streams and 37 users per channel
• Orthogonal frequency division multiple access (OFDMA) that allows multiple users to share the same channel with different subcarrier allocations
• 320 MHz channel bandwidth that enables higher data rates and spectral efficiency
• 4096 quadrature amplitude modulation (QAM) that increases the number of bits per symbol
• Multi-link operation that allows a device to connect to multiple access points (APs) simultaneously
• Enhanced power saving mechanisms that reduce the energy consumption and extend the battery life of devices

The other options are incorrect because they do not provide the same level of data rate as 802.11 be. 802.11 ac, or Wi-Fi 5, supports up to 1.73 Gbps of data rate in the 5 GHz band with 160 MHz channel bandwidth and 256 QAM. 802.11 ax, or Wi-Fi 6, supports up to 9.6 Gbps of data rate in both 2.4 GHz and 5 GHz bands with 160 MHz channel bandwidth, 1024 QAM, and OFDMA, but it is not a dual-band standard as it also supports the 6 GHz band. 802.11 n, or Wi-Fi 4, supports up to 600 Mbps of data rate in both 2.4 GHz and 5 GHz bands with 40 MHz channel bandwidth and 64 QAM. 802.1 lax and 802.1 In are not valid IEEE WLAN standards. References: IEEE 802.11be Extremely High Throughput: The Next Generation of Wi-Fi Technology Beyond 802.11ax, Wi-Fi Timeline, IEEE 802.11-2020

According to the Aruba Network Technician (ACNT) documents and learning resources, the valid configurable “Client VLAN Assignment” options for a Bridge-based WLAN in Aruba Central are native VLAN, automatic VLAN, and static VLAN. These options allow you to specify how the VLAN ID for the WLAN clients is determined.

• Native VLAN: This option allows you to use the native VLAN of the AP’s Ethernet port as the VLAN ID for the WLAN clients. The native VLAN is the default VLAN that carries untagged traffic on a trunk port. This option is useful when you want to simplify the VLAN configuration and use the same VLAN for all the WLAN clients connected to the same AP.
• Automatic VLAN: This option allows you to use the VLAN ID assigned by a DHCP server to the WLAN clients. The DHCP server can use attributes such as MAC address, hostname, or vendor class to assign different VLAN IDs to different WLAN clients. This option is useful when you want to dynamically assign VLANs based on the client characteristics or policies.
• Static VLAN: This option allows you to specify a single VLAN ID for all the WLAN clients. You can either enter a VLAN ID manually or select a named VLAN from the drop-down list. A named VLAN is a VLAN that has a user-defined name associated with it for easy identification. This option is useful when you want to assign a fixed VLAN to a WLAN SSID.

References:

Layer 2 encapsulation is the process of adding a header and a trailer to the data coming from the upper layer (Layer 3) before sending it over the physical medium. The header and the trailer contain information such as source and destination MAC addresses, error detection, and protocol type. The devices that perform Layer 2 encapsulation are usually switches, bridges, or network interface cards (NICs). In the given network diagram, the PC is sending a message to the server. The PC first adds a Layer 2 header and trailer to the data and sends it to Switch-1. Switch-1 performs Layer 2 encapsulation again before forwarding it to the router. The router operates at Layer 3 and does not perform Layer 2 encapsulation. It only removes the Layer 2 header and trailer, checks the destination IP address, and forwards the packet to the next hop. The packet then reaches Switch-2, where Layer 2 encapsulation occurs again before it is sent to the server. The server also performs Layer 2 de-encapsulation by removing the header and trailer and passing the data to the upper layer. Therefore, the devices that have performed Layer 2 encapsulation by the time the message arrives at the server are Switch-1 and Switch-2. References: Understanding Data Link Layer Encapsulation, How Data Encapsulation & De-encapsulation Works?, HDLC Protocol and Encapsulation method Explained

To convert a hexadecimal number to a binary number, we need to follow these steps:

• Write down the hexadecimal number and assign a power of 16 to each digit, starting from the rightmost with 16^0.
• Convert each hexadecimal digit to its decimal equivalent by multiplying it with its power of 16.
• Add all the decimal values to get the decimal equivalent of the hexadecimal number.
• Divide the decimal number by 2 repeatedly and write down the remainders from bottom to top.
• The binary number is the sequence of remainders obtained in the previous step.

Let’s apply these steps to the hexadecimal number 17:

• 17 = 1 × 16^1 + 7 × 16^0
• 17 = 16 + 7
• 17 = 23 in decimal
• 23 / 2 = 11 with remainder 1
• 11 / 2 = 5 with remainder 1
• 5 / 2 = 2 with remainder 1
• 2 / 2 = 1 with remainder 0
• 1 / 2 = 0 with remainder 1
• The binary number is 10111

Therefore, the binary equivalent of the hexadecimal number 17 is 10111 (option B).

References: The answer can be verified by using the following resources:

• Hexadecimal to Binary Converter - Binary Hex Converters
• How to Convert 17 from hexadecimal to binary - Calculator Online
• Convert hexadecimal number 17 to binary - CoolConversion
• 17 in Binary - How to Convert 17 from Decimal to Binary? - Cuemath

The subnet mask 255.255.252.0 is equivalent to the CIDR notation /22, which means that 22 bits are used for the network prefix and 10 bits are used for the host part. To calculate the number of addresses that this subnet mask provides, we can use the formula2n−2, wherenis the number of bits in the host part. In this case,n=10, so the number of addresses is210−2=1024−2=1022. The subtraction of 2 is because the first and the last addresses are reserved for the network identifier and the broadcast address, respectively. Therefore, the subnet mask 255.255.252.0 provides 1022 usable addresses for hosts, plus 2 reserved addresses, for a total of 1024 addresses.References:IP Subnet Calculator,How many host addresses are available on the network … - ITExamAnswers

 Adjacent Channel Interference (ACI) is a type of interference that occurs when two or more wireless devices use channels that are close to each other in the same frequency band. ACI reduces the signal quality and throughput of the wireless devices, as they have to compete for the same spectrum and deal with the noise from the neighboring channels12

The 5 GHz band has more non-overlapping channels than the 2.4 GHz band, which means that there is less chance of ACI in the 5 GHz band. However, ACI can still occur in the 5 GHz band if the wireless devices use wider channel bandwidths, such as 40 MHz or 80 MHz, which are supported by 802.11n and 802.11ac standards. Wider channel bandwidths can increase the data rate and performance of the wireless devices, but they also occupy more spectrum and reduce the number of available channels134

Therefore, one condition that allows 5 GHz channels to avoid ACI is to transmit at 20 MHz bandwidth, which is the narrowest channel bandwidth supported by 802.11a/n/ac standards. By transmitting at 20 MHz bandwidth, the wireless devices can use more non-overlapping channels in the 5 GHz band and minimize the impact of ACI. However, this alsomeans that the wireless devices will have lower data rates and performance than using wider channel bandwidths134

Another condition that can help avoid ACI in the 5 GHz band is to use channel bonding, which is a technique that combines two or more adjacent channels into one wider channel. Channel bonding can increase the data rate and performance of the wireless devices, but it also requires careful planning and coordination to avoid overlapping with other wireless devices. Channel bonding can be done with 40 MHz or 80 MHz channel bandwidths, but not with 20 MHz channel bandwidths134 References: 

https://www.ti.com/pdfs/bcg/80211_acr_wp.pdf

https://www.ti.com/pdfs/bcg/80211_acr_wp.pdf

ARP is a protocol that maps an IP address to a MAC address, which is the physical address of a device on a network. ARP is necessary because the software address (IP address) of the host or computer connected to the network needs to be translated to a hardware address (MAC address). Without ARP, a host would not be able to figure out the hardware address of another host. ARP works by sending a broadcast message to all devices on the network, asking for the MAC address of the device that has a specific IP address. The device that has that IP address replies with its MAC address, and the sender stores this information in its ARP cache for future use. The sender then uses the MAC address as the destination address of the Layer 2 header that encapsulates the IP packet. The Layer 2 header is also known as the data link layer header, which is responsible for delivering the packet to the correct device on the same network. The Layer 3 header is also known as the network layer header, which is responsible for routing the packet to the correct network. Therefore, the correct answer is C, because ARP is used to discover the destination address of the Layer 2 header that encapsulates IP packets1234 References: What Is Address Resolution Protocol (ARP)? - Fortinet, Address Resolution Protocol - Wikipedia, ARP (Address Resolution Protocol) explained - Study-CCNA, Aruba Certified Network Technician Exam HPE3-U01 Actual Questions

In the 2.4 GHz band, only channels 1, 6, and 11 are non-overlapping, meaning that they do not share any frequency spectrum with each other. This makes them the preferred channels for Wi-Fi networks to minimize interference with other devices that use the same band, such as Bluetooth, microwave ovens, cordless phones, etc. Using non-overlapping channels also allows for better performance and throughput, as devices on the same channel have to contend for the medium and avoid collisions. Channels 2 to 5 overlap with channel 1, channels 7 to 10 overlap with channel 6, and channels 12 and 13 overlap with channel 11. Channel 14 is not allowed in most countries and regions, and it also overlaps with channel 11. Therefore, using any of these channels would cause interference with the non-overlapping channels and degrade the network quality. The 2.4 GHz band has a total of 14 channels, each with a bandwidth of 22 MHz and a center frequency separated by 5 MHz. However, the actual frequency range used by each channel is wider than 22 MHz, as the signal spreads out due to modulation. This means that adjacent channels partially overlap with each other, and only channels that are 25 MHz apart or more are completely non-overlapping. The following table shows the center frequency and frequency range of each channel in the 2.4 GHz band:

Table

Channel

Center frequency (MHz)

Frequency range (MHz)

1

2412

2401-2423

2

2417

2406-2428

3

2422

2411-2433

4

2427

2416-2438

5

2432

2421-2443

6

2437

2426-2448

7

2442

2431-2453

8

2447

2436-2458

9

2452

2441-2463

10

2457

2446-2468

11

2462

2451-2473

12

2467

2456-2478

13

2472

2461-2483

14

2484

2473-2495

As shown in the table, only channels 1, 6, and 11 have a 25 MHz separation between their center frequencies, and therefore do not overlap with each other or any other channel. This makes them the best choice for Wi-Fi communications in the 2.4 GHz band. References:

• Aruba Certified Network Technician (ACNT) | HPE Aruba Networking
• Aruba Documentation Portal
• List of WLAN channels - Wikipedia
• Why Channels 1, 6 and 11? | MetaGeek
• All about WiFi Channels & Frequency Bands – A simple Guide
• WiFi Channels: Complete Guide with Tips to Boost Signal Performance