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

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

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 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 OSI model is a conceptual framework that describes the process of transmitting data between computers. It is divided into seven layers, each with a specific function. The application layer, or layer 7, is the highest layer of the OSI model and is responsible for creating data. The application layer provides services such as resource sharing, remote file access, email, web browsing, etc. The data created by the application layer is then passed down to the presentation layer, which translates it into a common format for the lower layers. The data is then further processed by the session, transport, network, data link, and physical layers until it reaches the destination12 References:

• What is OSI Model | 7 Layers Explained
• OSI model - Wikipedia

In order to allow inter-PC communication in the same broadcast domain, both switches need to have the same VLAN configured on the ports that connect to the PCs and the trunk port that connects to each other. Option B shows the correct configuration for both switches, as follows:

• On Switch-1, interface 0/1 is configured as an access port on VLAN 10, which matches the VLAN of PC-1. Interface 0/2 is configured as a trunk port, which allows VLAN 10 traffic to pass through to Switch-2.
• On Switch-2, interface 0/1 is configured as an access port on VLAN 10, which matches the VLAN of PC-2. Interface 0/2 is also configured as a trunk port, which allows VLAN 10 traffic to pass through from Switch-1.

Option A is incorrect because it does not configure the trunk port on Switch-2, which prevents VLAN 10 traffic from reaching Switch-1. Option C is incorrect because it configures the trunk port on Switch-1 with the wrong encapsulation mode (ISL instead of dot1q), which causes a mismatch with Switch-2. Option D is incorrect because it configures the access ports on Switch-2 with the wrong VLAN (20 instead of 10), which isolates PC-2 from PC-1.

References:

1: Layer 2 VLAN Configuration on a Cisco Switch (with Example) - Networks Training 2: VLAN Configuration Commands Step by Step Explained - Computer Networking Notes 3: How To Configure VLANs On the Catalyst Switches - Cisco Community 4: Configure VLAN on Cisco Switch Using Cisco Packet Tracer - TECHNIG

 The TCP three-way handshake is a process that is used in a TCP/IP network to create a connection between a client and a server. It involves the exchange of three packets: SYN, SYN-ACK, and ACK. The goal of the TCP three-way handshake is to establish a reliable, flow-controlled connection between the two endpoints. This means that the connection is able to ensure that the data is transmitted without errors, losses, or duplications, and that the data is sent at a rate that both sides can handle.

The TCP three-way handshake works as follows:

• The client initiates the connection by sending a SYN packet to the server. The SYN packet contains a random sequence number that indicates the starting point of the data that the client will send.
• The server responds to the client by sending a SYN-ACK packet. The SYN-ACK packet contains the server’s own sequence number and an acknowledgment number that is equal to the client’s sequence number plus one. This indicates that the server has received the client’s SYN packet and is ready to receive data from the client.
• The client completes the handshake by sending an ACK packet to the server. The ACK packet contains an acknowledgment number that is equal to the server’s sequence number plus one. This indicates that the client has received the server’s SYN-ACK packet and is ready to send data to the server.

After the TCP three-way handshake is completed, the connection is established and the data transfer can begin.

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

• TCP 3-Way Handshake Process - GeeksforGeeks
• TCP 3-Way Handshake (SYN, SYN-ACK,ACK) - Guru99
• Akamai Blog | What is a TCP Three-Way Handshake?
• What is a Three-Way Handshake? - Definition from Techopedia
• What is TCP 3-Way Handshake, Benefits, and Drawbacks? - Networking Signal

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 Wi-Fi frame is a unit of data transmission in a wireless network that follows the 802.11 standard. There are three types of Wi-Fi frames: management, control, and data. Management frames are used to establish and maintain the connection between wireless devices, such as access points (APs) and stations (STAs). Control frames are used to coordinate the access to the wireless medium and avoid collisions. Data frames are used to carry the actual information between wireless devices1

A Service Set Identifier (SSID) is a name that identifies a wireless network. A Basic Service Set Identifier (BSSID) is a unique identifier for a wireless access point within a wireless network. A BSSID is usually the MAC address of the wireless interface of the AP. An SSID can be associated with multiple BSSIDs, forming an Extended Service Set (ESS). For example, a wireless network with multiple APs can have the same SSID but different BSSIDs for each AP23

A beacon is a type of management frame that is periodically broadcasted by an AP to announce its presence and provide information about the wireless network, such as the SSID, the BSSID, the supported data rates, the security parameters, and the channel number. A beacon is used by STAs to discover and join a wireless network, as well as to synchronize their clocks with the AP. A beacon is usually sent every 100 milliseconds on a fixed interval45

Therefore, the Wi-Fi frame that announces the SSID to BSSID mapping is the beacon, as it contains both the SSID and the BSSID fields in its frame format. The other options are not correct because:

• An association request is a type of management frame that is sent by a STA to an AP to request to join a wireless network. It contains the SSID of the network that the STA wants to join, but not the BSSID of the AP. The BSSID is specified in the association response frame that is sent by the AP to the STA to accept or reject the request4
• A probe request is a type of management frame that is sent by a STA to scan for available wireless networks. It can contain the SSID of a specific network that the STA wants to join, or it can be blank to request information from all networks. It does not contain the BSSID of any AP. The BSSID is specified in the probe response frame that is sent by the AP to the STA to provide information about the network4
• A network allocation vector (NAV) is not a type of Wi-Fi frame, but a mechanism to avoid collisions in a wireless network. It is a timer that indicates how long the wireless medium will be busy for a transmission. Each Wi-Fi frame contains a duration field that specifies the NAV value for that transmission. The NAV value is updated by the wireless devices based on the duration field of the received frames. A wireless device will not transmit any frame if the NAV value is greater than zero, meaning that the medium is occupied.

References: 1: Wi-Fi Frames: A Brief Intro - Cisco Blogs 2: SSID vs BSSID: What’s the Difference? - Actiontec.com 3: Difference Between BSSID and SSID | Difference Between 4: 802.11Management Frames - Tutorialspoint 5: [Beacon frame - Wikipedia] : [Association Request frame - 802.11 Wireless Networks: The Definitive Guide, 2nd Edition [Book]] : [Probe Request frame - 802.11 Wireless Networks: The Definitive Guide, 2nd Edition [Book]] : [Network Allocation Vector - an overview | ScienceDirect Topics] : [NAV (Network Allocation Vector) - GeeksforGeeks]

 Unicast is a type of data transmission where a message is sent from one sender to one receiver, each identified by a network address. Unicast is a one-to-one communication, as opposed to broadcast and multicast, which are one-to-many communications. Unicast is typically used for real-time data streams, such as video, audio, or online presentations, that are shared with a single user over the Internet. Unicast can also be used for email, file transfer, and other applications that require a specific recipient. References: Unicast - Wikipedia, Difference between Unicast, Broadcast and Multicast in Computer Network - GeeksforGeeks, Unicast Definition - TechTerms.com

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:

 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

The binary equivalent of the decimal number of 233 is 11101001. To find this, we can use the following method:

• Divide 233 by 2 and write down the remainder. The remainder is either 0 or 1.
• Divide the quotient by 2 and write down the new remainder.
• Repeat this process until the quotient is 0.
• Write the remainders from the bottom to the top. This is the binary equivalent.

For example:

Table

Quotient

Remainder

233 / 2

1

116 / 2

0

58 / 2

0

29 / 2

1

14 / 2

0

7 / 2

1

3 / 2

1

1 / 2

1

0 / 2

0

The remainders from the bottom to the top are 11101001, which is the binary equivalent of 233.

References:

1: Decimal to Binary Converter - RapidTables 2: How to Convert Decimal to Binary - wikiHow 3: Decimal to Binary Conversion Methods - GeeksforGeeks

A BSSID is a 48-bit label that identifies a basic service set (BSS) within a wireless network. A BSS is a subgroup of devices that share physical-layer medium access characteristics, such as radio frequency, modulation scheme, and security settings. A BSSID is usually the MAC address of the access point (AP) that creates the BSS, or a randomly generated value in an ad hoc network. A BSSID is different from an SSID, which is the name of the wireless network that users see and connect to. An SSID can have multiple BSSIDs associated with it, depending on the number and location of the APs. A BSSID is used to differentiate between different BSSs and to facilitate roaming and load balancing among them. References: https://internetspeedtest.world/wiki/bssid

https://www.minthaik.com/bssid-basic-service-set-identifier/

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

 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