Pass the HP Aruba ACNT HPE3-U01 Questions and answers with ValidTests

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

Radio frequency (RF) power is the amount of energy radiated by an antenna or a transmitter in the form of electromagnetic waves. RF power can be measured in different units, such as watts (W), milliwatts (mW), or decibels (dB). However, some units are more convenient than others for expressing RF power due to its logarithmic nature1

Logarithmic units, such as dB, are useful for comparing power levels that span several orders of magnitude, such as the power output of a radio station versus the power received by a mobile device. Logarithmic units also simplify the calculation of power ratios, gains, and losses, as they can be added or subtracted instead of multiplied or divided12

One common logarithmic unit for RF power is the decibel relative to milliwatt (dBm), which is defined as the power level in dB with reference to 1 mW. For example, 0 dBm means 1 mW, 10 dBm means 10 mW, 20 dBm means 100 mW, and so on. Conversely, -10 dBm means 0.1 mW, -20 dBm means 0.01 mW, and so on. The dBm unit is convenient because many RF signals, especially in wireless communication, are at fairly low power levels, and the dBm unit can express them in a short form23

Another logarithmic unit for RF power is the decibel relative to isotrope (dBi), which is defined as the power level in dB with reference to an isotropic radiator, which is a hypothetical antenna that radiates equally in all directions. The dBi unit is used to measure the gain of an antenna, which is the ratio of the power radiated by the antenna in a specific direction to the power radiated by an isotropic radiator. For example, a 3 dBi antenna means that it radiates 3 dB more power than an isotropic radiator in its main direction. The dBi unit is not suitable for expressing absolute power levels, as it depends on the reference antenna45

Therefore, the recommended unit of measurement for expressing RF power due to its logarithmic nature is the dBm, as it is an absolute unit that can compare power levels across a wide range and simplify power calculations. The dBi unit is only used for expressing antenna gain, which is a relative unit that depends on the reference antenna. The other units, such as lumens and milliwatts, are not logarithmic and are not commonly used for RF power measurement12345 References: 1: Radio frequency - Wikipedia 2: dBm - Wikipedia 3: RF power measurement, Part 1: Why and where - Analog IC Tips 4: Radiant intensity - Wikipedia 5: Fundamentals of RF and Microwave Power Measurements - UC Davis

The 051 Model is a reference model that describes how data communications occur on a network using five layers: physical, data link, network, transport, and application. The 051 Model is based on the OSI Model, which has seven layers, but it simplifies the presentation and session layers into the application layer. The 051 Model is used to understand the functions and interactions of different network components, such as devices, protocols, and services. Each layer of the 051 Model has a specific role and responsibility in the data communication process, as follows:

The physical layer defines the electrical and mechanical characteristics of the transmission medium, such as cables, connectors, and signals. It also determines how data is encoded into bits and transmitted over the medium.

The data link layer defines the rules and methods for accessing and sharing the transmission medium among multiple devices. It also provides error detection and correction mechanisms to ensure reliable data delivery.

The network layer defines the logical addressing and routing schemes for data packets across different networks. It also provides congestion control and fragmentation/reassembly functions to optimize network performance.

The transport layer defines the end-to-end communication and reliability services for data segments between applications. It also provides flow control and multiplexing/demultiplexing functions to manage data streams.

The application layer defines the protocols and services that enable user applications to exchange data over the network. It also provides functions such as encryption, authentication, and compression to enhance data security and efficiency.

References:

051 Model

OSI Model

Network Fundamentals

A collision occurs when two or more devices try to transmit data at the same time on a shared medium, such as a bus or a hub. Collisions degrade network performance and cause data loss. Switches mitigate collisions by creating separate collision domains for each port. This means that each port can transmit and receive data without interfering with other ports. Switches also use full-duplex communication, which allows simultaneous transmission and reception of data on each port, further reducing the chances of collisions. VLANs and L3 protocols do not affect collisions, as they operate at different layers of the network model. Proprietary features are not a general characteristic of switches, and may not be compatible with other vendors’ switches. References: Aruba Certified Network Technician (ACNT) | HPE Aruba Networking, Aruba Documentation Portal

To save the switch configuration changes, so they survive a switch reboot, you can use either the write memory or the save memory command. Both commands perform the same function, which is to copy the running configuration to the startup configuration. The running configuration is the current active configuration in the switch’s RAM, while the startup configuration is the configuration that is loaded when the switch boots up. By saving the configuration changes to the startup configuration, you ensure that they are preserved after a reboot12. The other commands are not valid for saving the configuration changes. The copy running-config checkpoint backup and copy running-config checkpoint startup-config commands are used to create checkpoints, which are snapshots of the running configuration that can be used to roll back changes in case of errors3. The store memory command does not exist in Aruba switches. References: 1: Saving Configuration Changes - Aruba 2: [ArubaOS-Switch 16.10 CLI Reference Guide] 3: [ArubaOS-Switch 16.10 Configuration and Management Guide] : https://www.arubanetworks.com/techdocs/ArubaOS-Switch_16.10/5200-6928.pdf : https://www.arubanetworks.com/techdocs/ArubaOS-Switch_16.10/5200-6929.pdf

The Institute of Electrical and Electronics Engineers (IEEE) is an organization that develops and publishes international standards for various fields of engineering, including electrical, electronic, computer, software, and telecommunications. IEEE standards are widely used and recognized by the industry, academia, and governments. IEEE standards cover topics such as wireless networking, Ethernet, power systems, smart grid, cybersecurity, robotics, biomedical engineering, and more. IEEE standards are developed by consensus among experts from different sectors and regions, and are reviewed and updated regularly to reflect the latest technologies and best practices. IEEE standards aim to promote innovation, interoperability, safety, reliability, and efficiency in engineering applications. References: IEEE Standards Association, IEEE - Wikipedia, IEEE Standards - Creative Safety Supply

DNS (Domain Name System) is the protocol that performs name to IP resolution. DNS is a hierarchical and distributed database that maps domain names to IP addresses and vice versa. DNS allows users to access network resources using human-readable names instead of numerical addresses. DNS also provides other information such as mail exchange servers, name servers, and text records. DNS operates on the application layer of the TCP/IP model and uses UDP port 53 for queries and responses. DNS consists of several components, such as resolvers, name servers, zones, and records. Resolvers are clients that send queries to name servers and receive responses. Name servers are servers that store and provide DNS information for a domain or a zone. Zones are logical partitions of the DNS namespace that are delegated to different name servers. Records are data entries that define the mapping between names and addresses or other attributes. References: https://www.geeksforgeeks.org/address-resolution-in-dns-domain-name-server/

https://networkencyclopedia.com/name-resolution/

https://www.ibm.com/docs/en/aix/7.2?topic=protocol-tcpip-name-resolution

The management plane is the logical path of all traffic related to the management of the device. Examples of protocols processed in the management plane are Simple Network Management Protocol (SNMP), Telnet, HTTP, Secure HTTP (HTTPS), and SSH. These management protocols are used for monitoring and for command-line interface (CLI) access12. Therefore, HTTPS and SSH are protocols that operate on the management plane, while the other options are not. TCP is a transport layer protocol that provides reliable data delivery for various applications, but it is not specific to the management plane3. ARP is a network layer protocol that resolves IP addresses to MAC addresses, but it is not used for device management4. STP is a data link layer protocol that prevents loops in switched networks, but it is not related to the management plane5. References: 1: Management Plane Protection - Cisco 2: Planes of Operation > IP Routing on Cisco IOS, IOS XE, and IOS XR: How … 3: [Transmission Control Protocol - Wikipedia] 4: [Address Resolution Protocol - Wikipedia] 5: [Spanning Tree Protocol - Wikipedia] : https://en.wikipedia.org/wiki/Transmission_Control_Protocol : https://en.wikipedia.org/wiki/Address_Resolution_Protocol : https://en.wikipedia.org/wiki/Spanning_Tree_Protocol

The table that clients must populate to remember the L2 addressing of their neighbors is the ARP table. ARP stands for Address Resolution Protocol, which is a protocol that maps an IP address to a MAC address1. A MAC address is a unique identifier for a network interface card (NIC) that operates at the data link layer (layer two) of the OSI model2. An IPaddress is a logical identifier for a device that operates at the network layer (layer three) of the OSI model3. When a client wants to communicate with another device on the same network, it needs to know the MAC address of the destination device. To do this, the client sends an ARP request, which is a broadcast message that asks “Who has this IP address?” The device that has the matching IP address replies with an ARP reply, which contains its MAC address. The client then stores this information in its ARP table, which is a cache of IP-to-MAC mappings. Therefore, statement B is correct. Statements A, C, and D are incorrect because they describe different types of tables. A MAC table is a table that a switch uses to store MAC addresses and the corresponding ports that they are connected to. A routing table is a table that a router uses to store the destination networks and the next-hop addresses that they are reachable through. An ethernet table is not a valid term in networking. References: 1: Aruba Certified Network Technician (ACNT) Study Guide, page 342: Aruba Certified Network Technician (ACNT) Study Guide, page 283: Aruba Certified Network Technician (ACNT) Study Guide, page 29. : Aruba Certified Network Technician (ACNT) Study Guide, page 35. : Aruba Certified Network Technician (ACNT) Study Guide, page 30. : Aruba Certified Network Technician (ACNT) Study Guide, page 31.

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