HP HP Certifications HPE6-A85 Questions & Answers

• Question 41:

  Which Protocol Data Unit (PDU) represents the data link layer PDU?

  A. PDU1 - Signal

  B. PDU2 - Frame

  C. PDU3 - Packet

  D. PDU4 - Segment

  Correct Answer: B

  Explanation: A frame is the data link layer PDU that encapsulates the network layer PDU (packet) with a header and a trailer that contain information such as source and destination MAC addresses, frame type, error detection, etc. A frame is transmitted over a physical medium such asEthernet, Wi-Fi, etc.

  References:https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/ar ubaos-solutions/1-overview/networking-basics.htm

• Question 42:

  Where are wireless client roaming decisions made?

  A. Client device

  B. Virtual Controller

  C. Joint decision made by the origination and destination APs

  D. Aruba Central

  Correct Answer: A

  Explanation: Wireless client roaming decisions are made by the client device based on its own criteria, such as signal strength, noise level, data rate, etc. The network can influence the client's roaming decision by providing information such as neighbor reports, load balancing, band steering, etc., but the final decision is up to the client.

  References:https://www.arubanetworks.com/techdocs/Instant_86_WebHelp/Content/instan t-ug/wlan-roaming/client-roaming.htm

• Question 43:

  Which statement is correct when comparing 5 GHz and 6 GHz channels with identical channel widths?

  A. 5 GHz channels travel the same distances and provide different throughputs to clients compared to 6 GHz channels

  B. 5 GHz channels travel different distances and provide different throughputs to clients compared to 6 GHz channels

  C. 5 GHz channels travel the same distances and provide the same throughputs to clients compared to 6 GHz channels

  D. 5 GHz channels travel different distances and provide the same throughputs to clients compared to 6 GHz channels

  Correct Answer: B

  Explanation: The correct statement when comparing 5 GHz and 6 GHz channels with identical channel widths is that 5 GHz channels travel different distances and provide different throughputs to clients compared to 6 GHz channels. This

  statement reflects the fact that higher frequency signals tend to have higher attenuation Attenuation is a general term that refers to any reduction in signal strength during transmission over distance or through an object or medium . Higher

  attenuation means that higher frequency signals have shorter range and lower throughput than lower frequency signals. Some facts about this statement are:

  5 GHz channels have lower frequency than 6 GHz channels, which means they have lower attenuation than 6 GHz channels.

  Lower attenuation means that 5 GHz channels can travel longer distances and provide higher throughputs to clients than 6 GHz channels with identical channel widths.

  However, the difference in distance and throughput between 5 GHz and 6 GHz channels may not be significant in indoor environments where there are many obstacles and reflections that affect signal propagation. The advantage of using 6

  GHz channels over 5 GHz channels is that they offer more spectrum availability, less interference, and more non-overlapping channels than 5 GHz channels.

  The other options are not correct because:

  5 GHz channels travel the same distances and provide different throughputs to clients compared to 6 GHz channels: This option is false because 5 GHz channels do not travel the same distances as 6 GHz channels due to higher attenuation

  of higher frequency signals.

  5 GHz channels travel the same distances and provide the same throughputs to clients compared to 6 GHz channels: This option is false because 5 GHz channels do not travel the same distances or provide the same throughputs as 6 GHz

  channels due to higher attenuation of higher frequency signals. 5 GHz channels travel different distances and provide the same throughputs to clients compared to 6 GHz channels: This option is false because 5 GHz channels do not provide

  the same throughputs as

  6 GHz channels due to higher attenuation of higher frequency signals.

  References: https://www.wi-fi.org/discover-wi-fi/wi-fi-certified-6e

  https://www.wi-fi.org/file/wi- fi-alliance-spectrum-needs-study

  https://www.cisco.com/c/en/us/support/docs/wireless- mobility/wireless-lan-wlan/82068-power-levels.html

  https://www.cisco.com/c/en/us/products/collateral/wireless/spectrum-expert-wi- fi/prod_white_paper0900aecd807395a9.html

• Question 44:

  What is indicated by a solid amber radio status LED on an Aruba AP?

  A. Not enough PoE is provided from the switch to power both radios of the AP

  B. The radio is working in mesh mode

  C. The radio is working the 5 GHz band only.

  D. The radio is enabled in monitor or spectrum analysis mode

  Correct Answer: D

  Explanation: The solid amber radio status LED on an Aruba AP Access Point (AP) Access Point (AP) is a device that connects wireless devices to a wired network using Wi-Fi or other wireless standards . APs act as transmitters and receivers of wireless signals and provide wireless coverage for a specific area . APs can operate in different modes such as root , repeater , bridge , mesh , etc . APs can also support different features such as security , QoS , roaming , load balancing , etc . APs can be standalone devices or managed by controllers or cloud services . APs can be verified by using commands such as show ap active , show ap database , show ap bss-table , etc . indicates that the radio is enabled in monitor or spectrum analysis mode. Monitor mode is a mode that allows the AP to scan all channels and collect information about wireless traffic, interference, rogue devices, etc. Spectrum analysis mode is a mode that allows the AP to scan all channels and collect information about RF Radio Frequency (RF) Radio Frequency (RF) is a term that refers to electromagnetic waves that have frequencies between 3 kHz and 300 GHz . RF waves are used for various purposes such as communication , broadcasting , radar , navigation , remote control , etc . RF waves can be modulated by changing their amplitude , frequency , or phase to encode information . RF waves can also be affected by various factors such as attenuation , reflection , refraction , diffraction , scattering , interference , noise , etc . RF waves can be measured by using devices such as spectrum analyzers , power meters , antennas , etc . environment, noise sources, channel utilization, etc. Both modes are useful for troubleshooting and optimizing wireless performance, but they disable normal data transmission and reception on the radio. The other options are not indicated by a solid amber radio status LED on an Aruba AP because: Not enough PoE is provided from the switch to power both radios of the AP: This option is false because not enough PoE Power over Ethernet (PoE) Power over Ethernet (PoE) is a technology that allows network devices to receive power and data over the same Ethernet cable . PoE eliminates the need for separate power sources and cables for devices such as IP phones , cameras , access points , etc . PoE is defined in IEEE 802.3af and IEEE 802.3at standards and supports different power classes and modes . PoE can be provided by switches or injectors that act as power sourcing equipment (PSE) and received by devices that act as powered devices (PD) . PoE can be verified by using commands suchas show power inline , show power-over-ethernet , debug ip device tracking , etc . is indicated by a blinking amber power status LED on an Aruba AP, not by a solid amber radio status LED. A blinking amber power status LED means that the AP is receiving insufficient power from the switch or injector and cannot operate normally. A solid green power status LED means that the AP is receiving sufficient power from the switch or injector and can operate normally. The radio is working in mesh mode: This option is false because the radio working in mesh mode is indicated by a solid green radio status LED on an Aruba AP, not by a solid amber radio status LED. A solid green radio status LED means that the radio is working in normal mode or mesh mode and can transmit or receive data on the assigned channel. Mesh mode is a mode that allows the AP to connect wirelessly to other APs and form a mesh network without requiring wired connections. The radio is working the 5 GHz band only: This option is false because the radio working in the 5 GHz band only is indicated by a solid blue radio status LED on an Aruba AP, not by a solid amber radio status LED. A solid blue radio status LED means that the radio is working in dual-band mode and can transmit or receive data on both 2.4 GHz and 5 GHz bands. References: https://www.arubanetworks.com/techdocs/Instant_86_WebHelp/Content/instant-ug/ap-led- behavior.htm https://www.arubanetworks.com/techdocs/Instant_86_WebHelp/Content/instant- ug/troubleshooting/ap-monitor-mode.htm https://www.arubanetworks.com/techdocs/Instant_86_WebHelp/Content/instant- ug/troubleshooting/ap-spectrum-analysis.htm

• Question 45:

  When would you bond multiple 20MHz wide 802.11 channels?

  A. To decrease the Signal to Noise Ratio (SNR)

  B. To increase throughput between the client and AP

  C. To provision highly available AP groups

  D. To utilize high gain omni-directional antennas

  Correct Answer: B

  Explanation: Bonding multiple 20MHz wide 802.11 channels is a technique to create a wider bandwidth channel that supports higher data rate transmissions. It can increase the throughput between the client and AP by using more spectrum resources and reducing interference.

  References:https://ieeexplore.ieee.org/document/9288995

• Question 46:

  Which commands are used to set a default route to 10.4.5.1 on an Aruba CX switch when ln-band management using an SVl is being used?

  A. iP default-gateway 10.4.5.1

  B. ip route 0 0 0.070 10.4 5.1 vrf mgmt

  C. ip route 0.0 0 0/0 10.4.5.1

  D. default-gateway 10.4.5.1

  Correct Answer: C

  Explanation: The command that is used to set a default route to 10.4.5.1 on an Aruba CX switch when in-band management using an SVI is being used is ip route 0.0 0 0/0 10.4.5.1 . This command specifies the destination network address

  (0.0 0 0) and prefix length (/0) and the next-hop address (10.4.5.1) for reaching any network that is not directly connected to the switch. The default route applies to the default VRF Virtual Routing and Forwarding. VRF is a technology that allows multiple instances of a routing table to co-exist within the same router at the same time. VRFs are typically used to segment network traffic for security, privacy, or administrative purposes. , which is used for in-band management traffic that goes through an SVI Switch Virtual Interface. SVI is a virtual interface on a switch that allows the switch to route packets between different VLANs on the same switch or different switches that are connected by a trunk link. An SVI is associated with a VLAN and has an IP address and subnet mask assigned to it12.

  References: https://www.arubanetworks.com/techdocs/AOS-CX/10_08/HTML/ip_route_4100i-6000- 6100-6200/Content/Chp_StatRoute/def-rou.htm https://www.arubanetworks.com/techdocs/AOS-CX/10_08/HTML/ip_route_4100i-6000- 6100-6200/Content/Chp_VRF/vrf-overview.htm

• Question 47:

  A network technician is using Aruba Central to troubleshoot network issues Which dashboard can be used to view and acknowledge issues when beginning the troubleshooting process?

  A. the Alerts and Events dashboard

  B. the Audit Trail dashboard

  C. the Reports dashboard

  D. the Tools dashboard

  Correct Answer: A

  Explanation: The Alerts and Events dashboard displays all types of alerts and events generated for events pertaining to device provisioning, configuration, and user management. You can use the Config icon to configure alerts and notifications for different alert categories and severities1. You can also view the alerts and events in the List view and Summary view2.

  References: https://www.arubanetworks.com/techdocs/central/latest/content/nms/alerts/configuring- alerts.htm https://www.arubanetworks.com/techdocs/central/latest/content/nms/alerts/viewing- alerts.htm

• Question 48:

  The noise floor measures 000000001 milliwatts, and the receiver's signal strength is - 65dBm. What is the Signal to Noise Ratio?

  A. 35 dBm

  B. 15 dBm

  C. 45 dBm

  D. 25 dBm

  Correct Answer: D

  Explanation: The signal to noise ratio (SNR) is a measure that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to the noise power, often expressed in decibels (dB). A high

  SNR means that the signal is clear and easy to detect or interpret, while a low SNR means that the signal is corrupted or obscured by noise and may be difficult to distinguish or recover3. To calculate the SNR in dB, we can use the following

  formula:

  SNR (dB) = Signal power (dBm) - Noise power (dBm) In this question, we are given that the noise floor measures -90 dBm (0.000000001 milliwatts) and the receiver's signal strength is -65 dBm (0.000316 milliwatts). Therefore, we can plug

  these values into the formula and get:

  SNR (dB) = -65 dBm - (-90 dBm) SNR (dB) = -65 dBm + 90 dBm SNR (dB) = 25 dBm Therefore, the correct answer is that the SNR is 25 dBm.

  References: https://en.wikipedia.org/wiki/Signal-to-noise_ratio

• Question 49:

  After having configured the edge switch uplink as requested your colleague says that they have failed to ping the core You ask your colleague to verify the connection is plugged in and the switch is powered on They confirm that both are correct You attempt to ping the core switch and confirm that the ping is failing. Knowing the nature of this deployment, what commands might you use to troubleshoot this issued

  A. Ping 10.11 1 - ping the core to attempt to verify connectivity Show trunk - to verify if the LAG interface was correctly added to the switch Show spanning tree - to check for spanning-tree blocked states Show port-access clients interface all

  - to view any port- access blocking states or failed authentication attempts on all interfaces Show run interface vlan20 - to double check the layer 3 svi configuration is correct for l_3 connectivity Show lldp neighors - to verify whether you are able to see the Core as an L2 neighbor to verify if the correct links are plugged in to the correct ports

  B. diagnostic diag cable-diag 1/1/51 diag cable-diag 1/1/52 - to view diagnostic information for the physical link to get a status on any interruptions to Layer 1 connectivity, show ip route - to verify that the default gateway is present in the routing table show ip ospf - to check whether there is a layer 3 routing protocol enabled show ip dns - to view whether there is a valid dns source

  C. Ping 10.1.1.1 - ping the core to attempt to verify connectivity show lacp agg - to verify which link aggregations are currently configured using which physical ports show lacp int - to verify the LACP status and whether any links are blocking in your topology show lldp neighors - to verify whether you are able to see the Core as an L2 neighbor to verify if the correct links are plugged in to the correct ports show run interface 1/1/51.1/1/52-to ensure the physical interfaces are no-shut and members of the lag show run interface lag 1 - to ensure the correct vlan trunking configuration is applied to the logical interface show run int vlan 20 - to ensure you have the L3 SVI no shut and configured in the correct subnet

  D. Show run - to view the running configuration of the switch Show run | begin 20 "vlan 20"

  - to ensure VLAN 20 was correctly added to the database show run | begin 20 'interface vlan 20' - to view the L3 SVI configuration Show run interface 1/1/51.1/1/52 - to ensure the physical interfaces are no shut and were added as

  members of LAG 1 Show run int lag 1 - to verify LACP mode active was configured to eliminate LACP blocking states

  Correct Answer: C

  Explanation: These commands might help troubleshoot this issue as they check various aspects of the connectivity between the edge switch and the core switch, such as Layer 3 reachability, Layer 2 adjacency, LACP configuration and status, VLAN trunking configuration, and interface status. References:https://www.arubanetworks.com/techdocs/AOS-CX_10_04/CLI/GUID- 8F0E7E8B-0F4B-4A3C-AE7F-0F1B5A7F9C5D.html

• Question 50:

  What is a weakness introduced into the WLAN environment when WPA2-Personal is used for security?

  A. It uses X 509 certificates generated by a Certification Authority

  B. The Pairwise Temporal Key (PTK) is specific to each session

  C. The Pairwise Master Key (PMK) is shared by ail users

  D. It does not use the WPA 4-Way Handshake

  Correct Answer: C

  Explanation: The weakness introduced into WLAN environment when WPA2-Personal is used for security is that PMK Pairwise Master Key (PMK) is a key that is derived from PSK Pre-shared Key (PSK) is a key that is shared between two parties before communication begins , which are both fixed. This means that all users who know PSK can generate PMK without any authentication process. This also means that if PSK or PMK are compromised by an attacker, they can be used to decrypt all traffic encrypted with PTK Pairwise Temporal Key (PTK) is a key that is derived from PMK, ANonce AuthenticatorNonce (ANonce) is a random number generated by an authenticator (a device that controls access to network resources, such as an AP), SNonce Supplicant Nonce (SNonce) is a random number generated by supplicant (a device that wants to access network resources, such as an STA), AA Authenticator Address (AA) is MAC address of authenticator, SA Supplicant Address (SA) is MAC address of supplicant using Pseudo-Random Function (PRF). PTK consists of four subkeys: KCK Key Confirmation Key (KCK) is used for message integrity check, KEK Key Encryption Key (KEK) is used for encryption key distribution, TK Temporal Key (TK) is used for data encryption, MIC Message Integrity Code (MIC) key. . The other options are not weaknesses because: It uses X 509 certificates generated by a Certification Authority: This option is false because WPA2-Personal does not use X 509 certificates or Certification Authority for authentication. X 509 certificates and Certification Authority are used in WPA2- Enterprise mode, which uses 802.1X and EAP Extensible Authentication Protocol (EAP) is an authentication framework that provides support for multiple authentication methods, such as passwords, certificates, tokens, or biometrics. EAP is used in wireless networks and point-to-point connections to provide secure authentication between a supplicant (a device that wants to access the network) and an authentication server (a device that verifies the credentials of the supplicant). for user authentication with a RADIUS server Remote Authentication Dial-In User Service (RADIUS) is a network protocol that provides centralized authentication, authorization, and accounting (AAA) management for users who connect and use a network service . The Pairwise Temporal Key (PTK) is specific to each session: This option is false because PTK being specific to each session is not a weakness but a strength of WPA2-Personal. PTK being specific to each session means that it changes periodically during communication based on time or number of packets transmitted. This prevents replay attacks and increases security of data encryption. It does not use the WPA 4-Way Handshake: This option is false because WPA2- Personal does use the WPA 4-Way Handshake for key negotiation. The WPA 4- Way Handshake is a process that allows the station and the access point to exchange ANonce and SNonce and derive PTK from PMK. The WPA 4-Way Handshake also allows the station and the access point to verify each other's PMK and confirm the installation of PTK.

  References: https://en.wikipedia.org/wiki/Wi-Fi_Protected_Access#WPA_key_hierarchy_and_management https://www.cwnp.com/wp- content/uploads/pdf/WPA2.pdf