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

The TCP/IP model is a hierarchical protocol for network communication. It consists of four layers: the application layer, the transport layer, the internet layer, and the network interface layer. Each layer has specific functions and protocols that enable data transmission over the internet123

The TCP/IP model does not specify how to compress, fragment, encrypt, or analyze data. These are functions that may be performed by some protocols at different layers, but they are not part of the TCP/IP model itself. Therefore, option B is incorrect.

The TCP/IP model does not depend on the underlying physical network or data link technology. It can work on any network that supports IP addressing and routing, such as Ethernet, Wi-Fi, ATM, etc. Therefore, options A and E are incorrect.

The TCP/IP model specifies how to assemble, address, transmit, route, and disassemble a data packet. This is the core function of the internet layer, which uses the Internet Protocol (IP) to perform these tasks. IP is responsible for delivering packets from the source to the destination, based on the IP addresses of the hosts. Therefore, option C is correct.

The TCP/IP model is a set of communication protocols used on IP-based networks only. This means that any network that supports the internet layer of the TCP/IP model can use the TCP/IP protocols. IP-based networks are the most common and widely used networks in the world, as they enable the interconnection of different networks and devices across the internet. Therefore, option D is correct. References: https://www.guru99.com/tcp-ip-model.html

https://www.javatpoint.com/computer-network-tcp-ip-model

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.

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

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

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

An omnidirectional antenna is an antenna that radiates almost equal power in all directions in the horizontal plane, which is also called the azimuth plane1. This means that the antenna has a 360-degree coverage in the horizontal plane, but a narrow coverage in the vertical plane, which is also called the elevation plane2. An omnidirectional antenna is suitable for indoor environments where the clients are distributed around the access point3. Therefore, statement D accurately describes an omnidirectional antenna. Statements A, B, and C are incorrect because they describe different types of antennas. Statement A describes an isotropic antenna, which is a theoretical antenna that radiates equal power in all directions in both the horizontal and vertical planes. Statement B describes a vertical antenna, which is an antenna that radiates almost equal power in all directions in the vertical plane, but a narrow coverage in the horizontal plane. Statement C describes a directional antenna, which is an antenna that radiates more power in a specific angle and less power in others, creating a focused beam of radio waves. References: 1: Aruba Certified Network Technician (ACNT) Study Guide, page 872: Aruba Certified Network Technician (ACNT) Study Guide, page 883: Aruba Certified Network Technician (ACNT) Study Guide, page 89. : Aruba Certified Network Technician (ACNT) Study Guide, page 87. : Aruba Certified Network Technician (ACNT) Study Guide, page 88. : Aruba Certified Network Technician (ACNT) Study Guide, page 89.

The digits in the ArubaOS-CX switch interface numbering represent the member, slot, and port numbers of the physical ports and their corresponding logical software interfaces. The format is member / slot / port, where:

• Member: Member number of the switch in a Virtual Switching Framework (VSF) stack. Range: 1 to 8. The primary switch is always member 1. VSF is a technology that allows multiple switches to operate as a single logical device, providing high availability, scalability, and simplified management.
• Slot: Slot number of the module on the switch chassis. Range: 1 to 6. The 6400 Switch Series has six slots for line cards, while the 8320, 8325, and 8400 Switch Series have four slots for line cards and two slots for management modules.
• Port: Port number of the interface on the module. Range: 1 to 48 for 1G/10G ports, 1 to 32 for 25G ports, and 1 to 8 for 40G/100G ports.

For example, interface 1/1/1 refers to the first port on the first module of the first switch in a VSF stack.

References:

• Identifying switch ports and interfaces
• ArubaOS-CX 10.05 Command-Line Interface Guide 6200 Switch Series
• ArubaOS-CX 10.04 Virtual Switching Extension (VSX) Guide

 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.

Full-duplex is a switchport feature that allows simultaneous transmission and reception of data on a link, without causing collisions. Collisions occur when two devices try to send data at the same time on a shared medium, such as a half-duplex link or a hub. Full-duplex eliminates the need for collision detection and avoidance mechanisms, such as CSMA/CD, and increases the effective bandwidth of the link. Full-duplex requires both ends of the link to support and be configured for full-duplex mode. If one end is configured for full-duplex and the other for half-duplex, the result is a duplex mismatch, which causes performance issues and errors. Auto speed is a switchport feature that allows the switch to negotiate the speed of the link with the connected device, such as 10 Mbps, 100 Mbps, or 1000 Mbps. VLANs are logical groups of devices that share the same broadcast domain, regardless of their physical location or connection. VLANs can reduce collisions by segmenting the network and limiting the scope of broadcasts. However, VLANs alone do not prevent collisions on a link, as they depend on the duplex mode of the switchport. Half-duplex is a switchport feature that allows only one direction of data transmission at a time on a link, either sending or receiving. Half-duplex requires collision detection and avoidance mechanisms, such as CSMA/CD, to coordinate the access to the shared medium. Half-duplex reduces the effective bandwidth of the link by half, as only one device can use the link at a time. Half-duplex can cause collisions if two devices try to send data at the same time on the same link. References:

• Aruba Certified Network Technician (ACNT) | HPE Aruba Networking
• Aruba Documentation Portal
• switch port collisions - Cisco Community
• Why is a switch port a collision domain? - Cisco Community

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 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

 A collision occurs when two or more devices try to transmit data at the same time on a shared medium, such as a cable or a wireless channel. Collisions result in corrupted or lost data, and reduce the efficiency of the network. Different connection types have different susceptibility to collisions, depending on how they handle data transmission and collision detection.

Dark fiber and fiber are optical connections that use light to transmit data. They are immune to electromagnetic interference and have very high bandwidth. They also use full-duplex communication, which means that data can be sent and received simultaneously on separate fibers. Therefore, collisions are very unlikely to happen on dark fiber and fiber connections.

Copper is an electrical connection that uses metal wires to transmit data. It is prone to electromagnetic interference and has lower bandwidth than optical connections. It can use either half-duplex or full-duplex communication, depending on the device and the protocol. Half-duplex communication means that data can only be sent or received at a time on the same wire. Therefore, collisions are more likely to happen on copper connections that use half-duplex communication, such as Ethernet hubs.

Wi-Fi is a wireless connection that uses radio waves to transmit data. It is also prone to electromagnetic interference and has lower bandwidth than optical connections. It uses half-duplex communication, which means that data can only be sent or received at a time on the same channel. Therefore, collisions are very likely to happen on Wi-Fi connections, especially when there are many devices using the same channel or frequency.

References:

• Types of Collisions
• What are elastic and inelastic collisions?
• Why is a switch port a collision domain?

OWE is a Wi-Fi technology that assists with data privacy on open networks by providing unauthenticated data encryption. OWE is based on the standard defined in RFC 8110, which specifies an extension to IEEE 802.11 that uses a cryptographic handshake to encrypt the devices connecting to open network access points. OWE reduces the risk of data exposure or theft when using an open Wi-Fi network, without adding complexity or scalability burdens. OWE is part of the Wi-Fi CERTIFIED Enhanced Open™ program, which is a new certification for Wi-Fi devices that support this technology123 References:

• Wi-Fi CERTIFIED Enhanced Open™: Transparent Wi-Fi … - Wi-Fi Alliance
• Debunking Wi-Fi® Security Myths: Cellular Networks are … - TechSpective
• 10. Use adequate security to send or receive health information over …

 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

Broadcast communication is the distribution of audio or video content to a dispersed audience via any electronic mass communications medium, using the electromagnetic spectrum (radio waves), in a one-to-many model1. A broadcast message is a message that is sent to all endpoints on the network, regardless of their address or identity2. An example of a broadcast message is an ARP request, which is used to find the MAC address of a device that has a specific IP address3. An ARP request is sent to the broadcast address of the network, which is usually the last address in the subnet (e.g., 192.168.1.255 for a /24 network). All devices on the network receive the ARP request and check if their IP address matches the one in the request. If so, they reply with their MAC address to the sender of the ARP request. If not, they ignore the request4. Therefore, an ARP request is an example of broadcast communication, while the other options are not. A DHCP offer is a message that is sent by a DHCP server to a specific client that requested an IP address5. An ICMP echo is a message that is sent by a device to test the connectivity and latency to another device. An HTTP Get is a message that is sent by a web browser to request a web page from a web server. These messages are not broadcast, but rather unicast, meaning they are sent to a single destination. References: 1: Broadcasting - Wikipedia 2: Broadcast communication network - Wikipedia 3: [Address Resolution Protocol - Wikipedia] 4: [How ARP Works - Cisco] 5: [DHCP - Wikipedia] : [Ping (networking utility) - Wikipedia] : [Hypertext Transfer Protocol - Wikipedia] : https://en.wikipedia.org/wiki/Address_Resolution_Protocol : https://www.cisco.com/c/en/us/support/docs/ip/dynamic-address-allocation- resolution/13718-5.html : https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol : https://en.wikipedia.org/wiki/Ping_(networking_utility) : https://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol