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

The PCs are not able to successfully establish bidirectional communication because they are on different subnets and their default gateways are not configured correctly. The default gateway is the IP address of the router interface that connects to the same subnet as the PC. The default gateway allows the PC to send packets to destinations outside its own subnet. In this case, PC-1 and PC-2 are on the 172.16.30.0/24 and 172.16.31.0/24 subnets respectively, and the router interfaces are 172.16.30.254 and 172.16.31.254 respectively. Therefore, the correct default gateway for PC-1 is 172.16.30.254 and the correct default gateway for PC-2 is 172.16.31.254. Changing PC-2’s default gateway to 172.16.31.254 will enable the communication between PC-1 and PC-212 References:

• Aruba Certified Network Technician (ACNT) - HPE Certification and Learning
• Aruba Certified Network Technician (ACNT) - Aruba Networks.

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

 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

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

• Write down the binary number and assign a power of 2 to each digit, starting from the rightmost with 2^0.
• Convert each binary digit to its decimal equivalent by multiplying it with its power of 2.
• Add all the decimal values to get the decimal equivalent of the binary number.

Let’s apply these steps to the binary number 10001010:

• 10001010 = 0 × 2^0 + 1 × 2^1 + 0 × 2^2 + 1 × 2^3 + 0 × 2^4 + 0 × 2^5 + 0 × 2^6 + 1 × 2^7
• 10001010 = 0 + 2 + 0 + 8 + 0 + 0 + 0 + 128
• 10001010 = 138 in decimal

Therefore, the decimal equivalent of the binary number 10001010 is 138 (option A).

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

• Convert 10001010 from binary to decimal - Calculator Online
• How to Convert decimal number 10001010 in binary? - CoolConversion
• 10001010 to decimal - Calculatio
• Binary Code | Binary: 10001010 | Decimal: 138 | Bits: 8

The command to access the second interface of the third slot in a modular ArubaOS-CX switch is interface 1/3/2. This is because the interface numbering format for modular switches is interface slot/module/port, where slot is the chassis slot number, module is the module number within the slot, and port is the port number within the module1. The slot number starts from 1, the module number starts from 0, and the port number starts from 12. Therefore, the second interface of the third slot is interface 1/3/2. The other options are incorrect because they do not follow the correct interface numbering format. References: AOS-CX 10.06 Command-Line Interface Guide 8320, 8

A router is a device that operates at the network layer (layer three) of the OSI model and forwards packets between different networks based on their destination IP addresses1. A router also utilizes routing protocols, such as OSPF, RIP, or BGP, to learn all possible paths to a destination network and select the best one based on a metric2. Therefore, statements D and E are true about a router. Statements A, B, and C are false because they describe the functions of a switch, a bridge, and a firewall, respectively3. References: 1: Aruba Certified Network Technician (ACNT) Study Guide, page 292: Aruba Certified Network Technician (ACNT) Study Guide, page 313: Aruba Certified Network Technician (ACNT) Study Guide, page 28.

 Wi-Fi is a wireless networking protocol that uses radio waves to communicate data over the air. Radio waves are electromagnetic waves that have different characteristics depending on their amplitude, phase, and frequency. Amplitude is the height of the wave, phase is the position of the wave relative to a reference point, and frequency is the number of cycles of the wave per second. To transmit data using Wi-Fi, these characteristics are modulated, or changed, according to a predefined scheme that encodes bits of information. For example, a high amplitude wave can represent a 1 bit, and a low amplitude wave can represent a 0 bit. Similarly, a positive phase shift can represent a 1 bit, and a negative phase shift can represent a 0 bit. Likewise, a high frequency wave can represent a 1 bit, and a low frequency wave can represent a 0 bit. By modulating these characteristics, Wi-Fi can transmit data in binary form over the air. Different modulation schemes can achieve different data rates and reliability, depending on the channel conditions and interference. Some common modulation schemes used by Wi-Fi are Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM), and Orthogonal Frequency Division Multiplexing (OFDM). References: Understanding Wi-Fi and How It Works, Introduction to Wi-Fi Wireless Networking, Wireless Communication - Overview, Wireless Communication | Set 1.

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 header in the exhibit belongs to the Internet Protocol version 4 (IPv4), which is the most widely used protocol for routing and delivering packets across networks. IPv4 is a connectionless and unreliable protocol that operates at the network layer of the OSI model. The IPv4 header consists of 20 bytes (160 bits) of fixed fields and up to 40 bytes (320 bits) of optional fields. The fixed fields include:

• Version: 4 bits that indicate the version of the IP protocol, which is 4 for IPv4.
• IHL (Internet Header Length): 4 bits that indicate the length of the IP header in 32-bit words, which is 5 for the minimum header size of 20 bytes.
• Type of Service: 8 bits that indicate the quality of service (QoS) parameters for the packet, such as precedence, delay, throughput, and reliability.
• Total Length: 16 bits that indicate the total length of the IP packet in bytes, including the header and the data.The maximum value is 65535 bytes.
• Identification: 16 bits that identify the packet for fragmentation and reassembly purposes.
• Flags: 3 bits that control the fragmentation of the packet. The first bit is reserved and must be zero. The second bit is the Don’t Fragment (DF) bit, which indicates whether the packet can be fragmented or not. The third bit is the More Fragments (MF) bit, which indicates whether the packet is the last fragment or not.
• Fragment Offset: 13 bits that indicate the position of the fragment in the original packet, measured in units of 8 bytes.
• TTL (Time To Live): 8 bits that indicate the maximum number of hops that the packet can traverse before being discarded. The TTL is decremented by one at each hop, and the packet is dropped if the TTL reaches zero.
• Protocol: 8 bits that indicate the protocol of the data carried in the packet, such as TCP, UDP, ICMP, etc. The protocol numbers are defined in the List of IP protocol numbers.
• Header Checksum: 16 bits that provide error detection for the IP header. The checksum is calculated by adding the 16-bit words of the header and taking the one’s complement of the result.The checksum is recomputed and verified at each hop.
• Source IP Address: 32 bits that indicate the IP address of the sender of the packet.
• Destination IP Address: 32 bits that indicate the IP address of the receiver of the packet.
• Options: Variable-length field that contains optional information for the IP packet, such as security, routing, timestamp, etc. The options are padded with zeros to make the header length a multiple of 32 bits.

The IPv4 header can be distinguished from other protocol headers by the value of the Version field, which is 4 for IPv4. Other protocol headers have different values for the Version field or do not have a Version field at all. For example, the IPv6 header has a Version field of 6, the UDP header does not have a Version field, the Ethernet header has a Type field instead of a Version field, and the TCP header has a Data Offset field instead of a Version field. References:

• Aruba Certified Network Technician (ACNT) | HPE Aruba Networking
• Aruba Documentation Portal
• Introduction and IPv4 Datagram Header - GeeksforGeeks
• Protocol header - Oxford Reference
• List of IP protocol numbers - Wikipedia

 Switches and routers are both networking devices that operate at different layers of the OSI model and perform different functions. The key differences between L2 switches and routers are:

• Switches operate at the data link layer (Layer 2) of the OSI model, while routers operate at the network layer (Layer 3). This means that switches forward frames based on the MAC addresses of the source and destination devices, while routers route packets based on the IP addresses of the source and destination networks.
• Switches build a MAC table that maps MAC addresses to switch ports, while routers build a routing table that maps IP addresses to next-hop interfaces. The MAC table is used by switches to determine which port to send a frame to, while the routing table is used by routers to determine which interface to send a packet to.
• Switches offer a considerably higher port density than routers, meaning that they can connect more devices to the network. Switches typically have dozens or hundreds of Ethernet ports, while routers usually have a few Ethernet ports and other types of ports such as ADSL, cable, fiber, dial-up, etc. Switches are used to create LAN segments, while routers are used to connect different networks or subnets.
• Switches are faster than routers because they do not take up time looking at the network layer header information. Switches can forward frames at wire speed, while routers need to process packets at the network layer and perform additional functions such as NAT, firewall, QoS, etc.

References: Switch (L2/L3) Vs Router: Comparison and Differences in TCP/IP Networks, Key Differences Between Routers and Different Types of Switches, Layer 2 Switch - How it operates, when to use it - Network Encyclopedia, Layer 2 switching - Study-CCNA, Differences Between Layer 2 and Layer 3 Switches｜Which one do you need？

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

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

 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

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

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