Free Practice Questions for HP HPE3-U01 Exam

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

IPv4 or Internet Protocol version 4 is the fourth version of the Internet Protocol that is used to identify and communicate with devices on the Internet. IPv4 uses a 32-bit address space, which means that each IPv4 address consists of 32 binary digits or bits. These bits can be expressed in different notations, such as decimal, hexadecimal, or binary. The most common notation is the dot-decimal notation, which divides the 32 bits into four groups of eight bits, called octets, and separates them by periods. For example, the IPv4 address 172.16.254.1 is equivalent to the binary address 10101100.00010000.11111110.00000001. The 32-bit address space of IPv4 allows for 2^32or 4,294,967,296 possible addresses, but some of them are reserved for special purposes, such as private networks or multicast addresses12345 References: https://en.wikipedia.org/wiki/Internet_Protocol_version_4

https://www.geeksforgeeks.org/what-is-ipv4/

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 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

An access point is a device that creates a wireless local area network (WLAN) by connecting wireless devices to a wired network. An access point performs two main functions: bridging and wireless connectivity.

Bridging is the process of forwarding data frames between different networks or network segments. An access point bridges wireless frames from wireless devices to the wired network, and vice versa, using the destination MAC address of the frame. This allows wireless devices to communicate with other devices on the same network or on different networks.

Wireless connectivity is the process of providing a wireless signal to wireless devices, such as laptops, smartphones, tablets, etc. An access point offers wireless connectivity to endpoints by broadcasting a service set identifier (SSID), which is the name of the wireless network. Wireless devices can scan for available SSIDs and connect to the access point by providing the correct security credentials, such as a password or a certificate.

The other statements are false because:

A. They use destination IP addresses to switch the packets. This is false because access points do not use IP addresses to switch packets. IP addresses are used at layer three of the OSI model, which is the network layer. Access points operate at layer two of the OSI model, which is the data link layer. Access points use MAC addresses to switch frames, not packets.

C. They are used to interconnect wireless devices only. This is false because access points are not used to interconnect wireless devices only. Access points are also used to connect wireless devices to a wired network, which may contain other devices, such as routers, switches, servers, etc.

E. They only operate at Layer three of the OSI model. This is false because access points do not operate at layer three of the OSI model, which is the network layer. Access points operate at layer two of the OSI model, which is the data link layer. Access points do not use network layer protocols, such as IP, to perform their functions. References:

What is an Access Point? - Cisco

Access Point | What is it and how it works?IAPP specification

 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

 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 enable internet access on a multilayer switch, you need to configure a default route that points to the ISP router as the next hop. A default route is a special type of static route that matches any destination IP address that is not found in the routing table. The syntax for adefault route is ip route 0.0.0.0 0.0.0.0 , where 0.0.0.0 0.0.0.0 means any IP address and any subnet mask. Alternatively, you can use the slash notation 0.0.0.0/0 to represent the same thing. Therefore, the correct configuration line to enter on the switch is ip route 0.0.0.0/0 172.16.31.254, which means that any traffic that is not destined for a local network will be forwarded to the ISP router at 172.16.31.254.

The other options are incorrect because they either use the wrong syntax or the wrong IP address. Option A uses the route command instead of the ip route command, which is not valid on a multilayer switch. Option C uses the routing command instead of the ip route command, which is also not valid on a multilayer switch. Option D uses the ip routing command instead of the ip route command, which is used to enable routing on the switch, not to configure a default route. Option D also omits the dots in the IP address and the subnet mask, which makes it invalid.

References:

What Is a Multilayer Switch and How to Use It?

Inter-VLAN Routing Configuration - 2024 Step-by-Step Tutorial

Multilayer Switch - Configuring IP Multilayer Switching