HPE6-A85 Sample Questions Answers

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

Aruba Central allows you to create device configuration groups that define common settings for devices within each group. You can create different types of groupsdepending on your network requirements and management preferences. Two types of groups that you can define in Aruba Central during group creation are:

• Template group: A template group allows you to create configuration templates using variables and expressions that can be applied to multiple devices or device groups. Template groups provide flexibility and scalability for managing large-scale deployments with similar configurations.
• Default group: A default group is automatically created when you add devices to Aruba Central for the first time. The default group contains basic configuration settings that are applied to all devices that are not assigned to any other group. You can modify or delete the default group as needed.

References: https://www.arubanetworks.com/techdocs/Central/latest/content/nms/device-groups.htm https://www.arubanetworks.com/techdocs/Central/latest/content/nms/template-groups.htm https://www.arubanetworks.com/techdocs/Central/latest/content/nms/default-group.htm

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

A static route is a route that is manually configured on a router or switch and does not change unless it is modified by an administrator. Static routes are used to specify how traffic should reach specific destinations that are not directly connected to the device or that are not reachable by dynamic routing protocols. In Aruba CX switches, static routes can be configured using the ip route command in global configuration mode. Based on the “show ip route” output on an Aruba CX 8400 switch, the route “10.1 20 0/24, vrf default via 10.1.12.2, [1/0]” is a static route because it has an administrative distance of 1 and a metric of 0, which are typical values for static routes. References: https://en.wikipedia.org/wiki/Static_routing https://www.arubanetworks.com/techdocs/AOS-CX_10_04/NOSCG/Content/cx-noscg/ip-routing/static-routes.htm https://www.arubanetworks.com/techdocs/AOS-CX_10_04/NOSCG/Content/cx-noscg/ip-routing/show-ip-route.htm

Multiple Pre-Shared Key (MPSK) is a feature that allows device-specific or group-specific passphrases to securely add headless devices to the WLAN Wireless Local Area Network. WLAN is a wireless computer network that links two or more devices using wireless communication to form a local area network (LAN) within a limited area such as a home, school, computer laboratory, campus, or office building. . MPSK enhances the WPA2 PSK Wi-Fi Protected Access 2 Pre-Shared Key. WPA2 PSK is a method of securing your network using WPA2 with the use of the optional Pre-Shared Key (PSK) authentication, which was designed for home users without an enterprise authentication server. mode by allowing different PSKs for different devices on the same SSID Service Set Identifier. SSID is a case-sensitive, 32 alphanumeric character unique identifier attached to the header of packets sent over a wireless local-area network (WLAN). The SSID acts as a password when a mobile device tries to connect to the basic service set (BSS) — a component of the IEEE 802.11 WLAN architecture. . MPSK passwords can be generated or user-created and are managed by ClearPass Policy Manager12. References: 1 https://blogs.arubanetworks.com/solutions/simplify-iot-authentication-with-multiple-pre-shared-keys/  2 https://www.arubanetworks.com/techdocs/ClearPass/6.8/Guest/Content/AdministrationTasks1/Configuring-MPSK.htm

The source that WPA3-Personal uses to generate a different Pairwise Master Key (PMK) each time a station connects to the wireless network is session-specific information (MACs and nonces). WPA3-Personal uses Simultaneous Authentication of Equals (SAE) to replace PSK authentication in WPA2-Personal. SAE is a secure key establishment protocol that uses a Diffie-Hellman key exchange to derive a shared secret between two parties without revealing it to an eavesdropper. SAE involves the following steps:

• The station and the access point exchange Commit messages that contain their MAC addresses and random numbers called nonces.
• The station and the access point use their own passwords and the received MAC addresses and nonces to calculate a shared secret called SAE Password Element (PE).
• The station and the access point use their own PE and the received MAC addresses and nonces to calculate a shared secret called SAE Key Seed (KS).
• The station and the access point use their own KS and the received MAC addresses and nonces to calculate a shared secret called SAE Key Confirmation Key (KCK).
• The station and the access point use their own KCK and the received MAC addresses and nonces to calculate a confirmation value called SAE Confirm.
• The station and the access point exchange Confirm messages that contain their SAE Confirm values.
• The station and the access point verify that the received SAE Confirm values match their own calculated values. If they match, the authentication is successful and the station and the access point have established a shared secret called SAE PMK.

The SAE PMK is different for each session because it depends on the MAC addresses and nonces that are exchanged in each authentication process. The SAE PMK is used as an input for the 4-way handshake that generates the Pairwise Temporal Key (PTK) for encrypting data frames.

The other options are not sources that WPA3-Personal uses to generate a different PMK each time a station connects to the wireless network because:

• Opportunistic Wireless Encryption (OWE): OWE is a feature that provides encryption for open networks without requiring authentication or passwords. OWE uses a similar key establishment protocol as SAE, but it does not generate a PMK. Instead, it generates a Pairwise Secret (PS) that is used as an input for the 4-way handshake that generates the PTK.
• Simultaneous Authentication of Equals (SAE): SAE is not a source, but a protocol that uses session-specific information as a source to generate a different PMK each time a station connects to the wireless network.
• Key Encryption Key (KEK): KEK is not a source, but an output of the 4-way handshake that generates the PTK. KEK is used to encrypt group keys that are distributed by the access point.

References: https://www.wi-fi.org/discover-wi-fi/wi-fi-certified-6e https://www.wi-fi.org/file/wi-fi-alliance-unlicensed-spectrum-in-the-us https://www.cisco.com/c/en/us/products/collateral/wireless/catalyst-9100ax-access-points/wpa3-dep-guide-og.html https://info.support.huawei.com/info-finder/encyclopedia/en/WPA3.html https://rp.os3.nl/2019-2020/p99/presentation.pdf

Aruba’s Captive Portal uses Layer 3 authentication, which means that it intercepts the client’s HTTP requests and redirects them to a web page where the client can enter their credentials. The credentials are then verified by a RADIUS server or a local database before granting network access. References:https://www.arubanetworks.com/techdocs/Instant_86_WebHelp/Content/instant-ug/captive-portal/captive-portal-auth.htm

The ideal access switch for a large hospital with distribution racks of over 400 ports in a single VSF stack is the CX 6300. This switch provides the following benefits:

• The CX 6300 supports up to 48 ports per switch and up to 10 switches per VSF stack, allowing for a total of 480 ports in a single stack. This meets the requirement of having over 400 ports in a single VSF stack.
• The CX 6300 supports high-performance switching with up to 960 Gbps of switching capacity and up to 714 Mpps of forwarding rate. This meets therequirement of having high throughput and low latency for mobile equipment and patient data.
• The CX 6300 supports advanced features such as dynamic segmentation, policy-based routing, and role-based access control. These features enhance the security and flexibility of the network by applying different policies and roles to different types of devices and users.
• The CX 6300 supports Aruba NetEdit, a network configuration and orchestration tool that simplifies the management and automation of the network. This reduces the complexity and human errors involved in network configuration and maintenance.

The other options are not ideal because:

• OCX 6400: This switch is designed for data center applications and does not support VSF stacking. It also does not support dynamic segmentation or policy-based routing, which are useful for network security and flexibility.
• OCX 6200: This switch is designed for small to medium-sized businesses and does not support VSF stacking. It also has lower switching capacity and forwarding rate than the CX 6300, which may affect the performance of the network.
• OCX 6100: This switch is designed for edge applications and does not support VSF stacking. It also has lower switching capacity and forwarding rate than the CX 6300, which may affect the performance of the network.

References: https://www.arubanetworks.com/assets/ds/DS_CX6300Series.pdf https://www.arubanetworks.com/assets/ds/DS_OC6400Series.pdf https://www.arubanetworks.com/assets/ds/DS_OC6200Series.pdf https://www.arubanetworks.com/assets/ds/DS_OC6100Series.pdf

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 recover1. When the signal from an AP Access Point. AP is a device that allows wireless devices to connect to a wired network using Wi-Fi, or related standards. weakens by being absorbed as it moves through an object, such as a wall or a furniture, the signal power decreases. This reduces the SNR and affects the quality of the wireless connection. The noise power may also increase due to interference from other sources, such as other APs or devices operating in the same frequency band2. Therefore, the correct answer is that SNR decreases when the signal from an AP weakens by being absorbed as it moves through an object. References: 1 https://en.wikipedia.org/wiki/Signal-to-noise_ratio  2 https://documentation.meraki.com/MR/Wi-Fi_Basics_and_Best_Practices/Signal-to-Noise_Ratio_%28SNR%29_and_Wireless_Signal_Strength

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: 1 https://www.arubanetworks.com/techdocs/AOS-CX/10_08/HTML/ip_route_4100i-6000-6100-6200/Content/Chp_StatRoute/def-rou.htm  2 https://www.arubanetworks.com/techdocs/AOS-CX/10_08/HTML/ip_route_4100i-6000-6100-6200/Content/Chp_VRF/vrf-overview.htm

TCP 3-Way Handshake sequence is:

• Step 1: The initiating host sends a packet with no data to the target host with a SEQ=1 and sets the SYN flag to 1.
• Step 2: The target host responds with a packet with ACK=2, SEQ=8, and the SYN and ACK flags set to 1.
• Step 3: The initiating host sends a packet with SEQ=2, ACK=9, and the ACK flag set to 1.
• Step 4: A normal-controlled connection is established.

References: https://en.wikipedia.org/wiki/Transmission_Control_Protocol https://www.cisco.com/c/en/us/support/docs/ip/routing-information-protocol-rip/13788-3.html

USE CASE: a) Controls the dynamic addition and removal of ports to groups Technology: 3) LACP

USE CASE: b) Tags Ethernet frames with an additional VLAN header Technology: 1) 802.1Q

USE CASE: c) Used to authenticate EAP-Capable client on a switch port Technology: 2) 802.1X

USE CASE: d) Used to identify a voice VLAN to an IP phone Technology: 4) LLDP

The following table summarizes the switching technologies and their use cases:

Technology

Use case

1) 802.1Q

802.1Q is a standard that defines how to create and manage virtual LANs (VLANs) on a network. VLANs allow network administrators to logically segment a network into different broadcast domains, improving security, performance, and manageability. 802.1Q tags Ethernet frames with an additional VLAN header that contains a VLAN identifier (VID), which indicates which VLAN the frame belongs to1.

2) 802.1X

802.1X is a standard that defines how to provide port-based network access control (PNAC) on a network. PNAC allows network administrators to authenticate and authorize devices before granting them access to network resources. 802.1X uses the Extensible Authentication Protocol (EAP) to exchange authentication messages between a supplicant (a device that wants to access the network), an authenticator (a device that controls access to the network, such as a switch), and an authentication server (a device that verifies the credentials of the supplicant, such as a RADIUS server)2.

3) LACP

LACP stands for Link Aggregation Control Protocol, which is part of the IEEE 802.3ad standard that defines how to bundle multiple physical links into a single logical link, also known as a link aggregation group (LAG) or an EtherChannel. LAGs provide increased bandwidth, load balancing, and redundancy for network connections. LACP controls the dynamic addition and removal of ports to groups, ensuring that only ports with compatible configurations can form a LAG3.

4) LLDP

LLDP stands for Link Layer Discovery Protocol, which is part of the IEEE 802.1AB standard that defines how to discover and advertise information about neighboring devices on a network. LLDP operates at Layer 2 of the OSI model and uses TLVs (type-length-value) to exchange information such as device name, port number, VLAN ID, capabilities, and power requirements. LLDP can be used to identify a voice VLAN to an IP phone by sending a TLV that contains the voice VLAN ID and priority.

References: 1 https://en.wikipedia.org/wiki/IEEE_802.1Q  2 https://en.wikipedia.org/wiki/IEEE_802.1X  3 https://en.wikipedia.org/wiki/Link_aggregation https://en.wikipedia.org/wiki/Link_Layer_Discovery_Protocol

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/arubaos-solutions/1-overview/networking-basics.htm

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: 1 https://www.arubanetworks.com/techdocs/central/latest/content/nms/alerts/configuring-alerts.htm  2 https://www.arubanetworks.com/techdocs/central/latest/content/nms/alerts/viewing-alerts.htm