HPE6-A85 Aruba Certified Campus Access Associate Exam Questions and Answers

In a Virtual Switching Extension (VSX) stack, the Virtual IP (VIP) provides a single default gateway IP address for clients connected to the access switch. This VIP is a floating IP that is active on the primary VSX switch. In the event of a failure of the primary switch, the VIP will failover to the secondary switch, ensuring that client traffic can continue to be routed without disruption.

AirMatch is a feature that provides centralized RF planning and optimization service for Aruba wireless networks. It uses cloud-based algorithms and machine learning to optimize the RF performance and user experience.References:https://www.arubanetworks.com/assets/ds/DS_AirMatch.pdf

In Aruba networks, the recommended Virtual Switching Framework (VSF) topologies include the daisy chain plus Multi-Active Detection (MAD) and the ring topology. The daisy chain topology with MAD provides a straightforward and effective way to connect multiple switches in a series while ensuring there is a mechanism in place (MAD) to detect and handle situations where more than one switch in the VSF might become active simultaneously. The ring topology offers redundancy by creating a looped connection pattern among the VSF members, enhancing network resilience and reliability.

In Aruba Central's network check page, you can run several diagnostic tests on switches. A ping test is a common utility to check the reachability of a host on an IP network. A Power over Ethernet (PoE) check can help verify the power delivery status to PoE-capable devices. These tests are crucial for ensuring connectivity and power supply to network devices

In large logistic facilities, to ensure comprehensive monitoring and performance analysis, it's recommended to place a User Experience Insight (UXI) sensor in every aisle. This allows for detailed and specific monitoring of network performance across the extensive coverage area of such facilities.

ICMP (Internet Control Message Protocol) is used by network devices to send error and operational information related to IP communications. It is used to send messages like "destination unreachable" or "time exceeded" when there are issues in IP communication

Virtual Router Redundancy Protocol (VRRP) is a network protocol that provides automatic assignment of available Internet Protocol (IP) routers to participating hosts. VRRP sends its messages over multicast for communication among routers for the election process of the master and advertisement of the virtual IP address.

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

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

Bonding multiple 20MHz wide 802.11 channels is a technique used to increase the throughput between the client device and the Access Point (AP). By combining two or more 20MHz channels into a wider channel (e.g., 40MHz, 80MHz, or even 160MHz), the data carrying capacity and, consequently, the overall throughput of the wireless connection are increased. This method is particularly useful in high-bandwidth applications or environments where higher data rates are required.

In the context of the OSI model, the network layer is responsible for packet forwarding including routing through intermediate routers. Hence, the network layer PDU is known as a packet.

 A slow amber-flashing Stack-LED indicates that stacking mode is selected on the switch. This means that the switch is ready to join a stack or form a new stack if no other switches are present.References:https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/1-overview/stacking-leds.htm

ClientMatch is an Aruba patented technology that helps to move sticky clients—clients that stay connected to an AP even when there are better APs available—to a more appropriate AP. This technology ensures that clients are always connected to the best available AP, optimizing both the client's performance and the overall performance of the wireless network.

The route "10.20.0.0/22, vrf default via 10.1.1.1, [110/200]" indicates that it is an OSPF route. This is evidenced by the administrative distance and metric "[110/200]" where 110 is the default administrative distance for OSPF routes.

QoS Quality of Service (QoS) is a set of techniques that manage network resources and provide different levels of service to different types of traffic based on their requirements. QoS can improve network performance, reduce latency, increase throughput, and prevent congestion. concept and its definition. Here is my answer:

QoS Concept:

Best Effort Service

Class of Service

Differentiated Services

WMM ====================== Definition:

d) A method where traffic is treated equally in a first-come, first-served manner a) A method for classifying network traffic at Layer 2 by marking 802.1Q VLAN Ethernet frames with one of eight service classes b) A method for classifying network traffic at Layer 3 by marking packets with one of 64 different service classes c) A method for classifying network traffic using access categories based on the IEEE 802.11e QoS standard

Short But Comprehensive Explanation of Correct Answer Only: The correct match between QoS concept and its definition is as follows:

Best Effort Service: This is a method where traffic is treated equally in a first-come, first-served manner without any prioritization or differentiation. This is the default service level for most networks and applications that do not have specific QoS requirements or guarantees. Best Effort Service does not provide any assurance of bandwidth, delay, jitter, or packet loss.

Class of Service: This is a method for classifying network traffic at Layer 2 by marking 802.1Q VLAN Ethernet frames with one of eight service classes (0 to 7). These service classes are also known as IEEE 802.1p priority values or PCP Priority Code Point (PCP) is a 3-bit field in the 802.1Q VLAN tag that indicates the priority level of an Ethernet frame . Class of Service allows network devices to identify and handle different types of traffic based on their priority levels. Class of Service is typically used in LAN Local Area Network (LAN) is a network that connects devices within a limited geographic area, such as a home, office, or building environments where Layer 2 switching is predominant.

Differentiated Services: This is a method for classifying network traffic at Layer 3 by marking packets with one of 64 different service classes (0 to 63). These service classes are also known as DiffServ Code Points (DSCP) DiffServ Code Point (DSCP) is a 6-bit field in the IP header that indicates the service class of a packet . Differentiated Services allows network devices to identify and handle different types of traffic based on their service classes. Differentiated Services is typically used in WAN Wide Area Network (WAN) is a network that connects devices across a large geographic area, such as a country or continent environments where Layer 3 routing is predominant.

WMM: This is a method for classifying network traffic using access categories based on the IEEE 802.11e QoS standard. WMM stands for Wi-Fi Multimedia and it is a certification program developed by the Wi-Fi Alliance to enhance QoS for wireless networks. WMM defines four access categories (AC): Voice, Video, Best Effort, and Background. These access categories correspond to different priority levels and contention parameters for wireless traffic. WMM allows wireless devices to identify and handle different types of traffic based on their access categories.

References: https://en.wikipedia.org/wiki/Quality_of_service https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/qos_dfsrv/configuration/xe-16/qos-dfsrv-xe-16-book/qos-dfsrv-overview.html https://www.cisco.com/c/en/us/support/docs/quality-of-service-qos/qos-packet-marking/10103-dscpvalues.html https://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/81831-qos-wlan.html https://www.wi-fi.org/discover-wi-fi/wi-fi-certified-wmm

The field in a Layer 3 IPv4 packet header that is used to mitigate Layer 3 route loops is Time To Live (TTL). TTL is an 8-bit field that indicates the maximum number of hops that a packet can traverse before being discarded. TTL is set by the source device and decremented by one by each router that forwards the packet. If TTL reaches zero, the packet is dropped and an ICMP Internet Control Message Protocol (ICMP) Internet Control Message Protocol (ICMP) is a network protocol that provides error reporting and diagnostic functions for IP networks. ICMP is used to send messages such as echo requests and replies (ping), destination unreachable, time exceeded, parameter problem, source quench, redirect, etc. ICMP messages are encapsulated in IP datagrams and have a specific format that contains fields such as type, code, checksum, identifier, sequence number, data, etc. ICMP messages can be verified by using commands such as ping , traceroute , debug ip icmp , etc . message is sent back to the source device. TTL is used to mitigate Layer 3 route loops because it prevents packets from circulating indefinitely in a looped network topology. TTL also helps to conserve network resources and avoid congestion caused by looped packets.

The other options are not fields in a Layer 3 IPv4 packet header because:

Checksum: Checksum is a 16-bit field that is used to verify the integrity of the IP header. Checksum is calculated by the source device and verified by the destination device based on the values of all fields in the IP header. Checksum does not mitigate Layer 3 route loops because it does not limit the number of hops that a packet can traverse.

Protocol: Protocol is an 8-bit field that indicates the type of payload carried by the IP datagram. Protocol identifies the upper-layer protocol that uses IP for datatransmission, such as TCP Transmission Control Protocol (TCP) Transmission Control Protocol (TCP) is a connection-oriented transport layer protocol that provides reliable, ordered, and error-checked delivery of data between applications on different devices . TCP uses a three-way handshake to establish a connection between two endpoints , and uses sequence numbers , acknowledgments , and windowing to ensure data delivery and flow control . TCP also uses mechanisms such as retransmission , congestion avoidance , and fast recovery to handle packet loss and congestion . TCP segments data into smaller units called segments , which are encapsulated in IP datagrams and have a specific format that contains fields such as source port , destination port , sequence number , acknowledgment number , header length , flags , window size , checksum , urgent pointer , options , data , etc . TCP segments can be verified by using commands such as telnet , ftp , ssh , debug ip tcp transactions , etc . , UDP User Datagram Protocol (UDP) User Datagram Protocol (UDP) is a connectionless transport layer protocol that provides

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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

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-hopaddress (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

In a 2.4GHz WLAN environment, channels 1, 6, and 11 are recommended for use simultaneously to avoid co-channel interference because these channels do not overlap with each other. Each of these channels is separated by enough frequency space to ensure that the signals do not interfere, which is not the case with other channel combinations.

Based on the exhibit showing the logging server configurations, server 172.17.17.43 will receive the smallest quantity of data because it is set to the "Warning" event log level. This means it will only log events that are categorized as warnings or higher severity, which are typically less frequent than lower severity levels such as "Information," "Debug," or "Emergency."

When checking the status of LACP (Link Aggregation Control Protocol) with the command "show lacp interfaces," various flags indicate the state of the LACP negotiation. "ALFOE" indicates different states for each letter: A (Activity), L (Link), F (Aggregation), O (Synchronization), and E (Collecting). In this context, the O flag is particularly of interest. If the O flag is not set (meaning the synchronization is not achieved), it typically suggests that LACP is not configured or not functioning correctly on the peer side, hence the link is not operational as part of an LACP channel.

When a network technician encounters an issue where a new SSID does not allow internet access despite successful connectivity and DNS resolution, they should verify the firewall policies associated with the new SSID. The firewall policies must include rules that permit traffic to and from the internet and should be correctly ordered to ensure that they are applied as intended. Since the existing SSID functions correctly, comparing the firewall rules between the two can be a useful method of troubleshooting.

To regain access to an Aruba CX switch when credentials are unknown or lost, one can press and hold the clear button, then power cycle the switch to reset the password. Additionally, using the boot profile 0 at the boot loader menu can be used to bypass the current startup configuration, which may include the unknown credentials.

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

Performing a hard reset on an Aruba CX switch typically involves pressing and holding the reset button for a specified amount of time, such as 5 seconds, and then releasing it. This action will initiate a reboot of the switch and return it to factory default settings, including the credentials.

When an Aruba AP is not receiving its configuration from Aruba Central, and other APs at the location are functioning normally, a common troubleshooting step is to disable and then re-enable the activation process on the AP. This action can trigger a provisioning refresh, prompting the AP to attempt to retrieve its configuration from Aruba Central again. This step is often effective in resolving communication or provisioning issues between the AP and the management platform.