HPE6-A85 Practice Exam Questions with Answers Aruba Certified Campus Access Associate Exam Certification

A UXI (User Experience Insight) is a device that simulates user behavior and tests network performance from the user perspective. It can check different applications, such as HTTP, VOIP, or Office 365, and measure metrics such as latency, jitter, packet loss, and throughput. References:https://www.arubanetworks.com/products/networking/user-experience-insight/

The reason why you would configure OSPF Open Shortest Path First (OSPF) is a link-state routing protocol that dynamically calculates the best routes for data transmission within an IP network. OSPF uses a hierarchical structure that divides a network into areas and assigns each router an identifier called router ID (RID). OSPF uses hello packets to discover neighbors and exchange routing information. OSPF uses Dijkstra’s algorithm to compute the shortest path tree (SPT) based on link costs and build a routing table based on SPT. OSPF supports multiple equal-cost paths, load balancing, authentication, and various network types such as broadcast, point-to-point, point-to-multipoint, non-broadcast multi-access (NBMA), etc. OSPF is defined in RFC 2328 for IPv4 and RFC 5340 for IPv6. to use the IP address IP address Internet Protocol (IP) address is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. An IP address serves two main functions: host or network interface identification and location addressing. There are two versions of IP addresses: IPv4 and IPv6. IPv4 addresses are 32 bits long and written in dotted-decimal notation, such as 192.168.1.1. IPv6 addresses are 128 bits long and written in hexadecimal notation, such as 2001:db8::1. IP addresses can be either static (fixed) or dynamic (assigned by a DHCP server). 10.1.200.1 as the router ID Router ID (RID) Router ID (RID) is a unique identifier assigned to each router in a routing domain or protocol. RIDs are used by routing protocols such as OSPF, IS-IS, EIGRP, BGP, etc., to identify neighbors, exchange routing information, elect designated routers (DRs), etc. RIDs are usually derived from one of the IP addresses configured on the router’s interfaces or loopbacks, or manually specified by network administrators. RIDs must be unique within a routing domain or protocol instance. is that the loopback interface state Loopback interface Loopback interface is a virtual interface on a router that does not correspond to any physical port or connection. Loopback interfaces are used for various purposes such as testing network connectivity, providing stable router IDs for routing protocols, providing management access to routers, etc. Loopback interfaces have some advantages over physical interfaces such as being always up unless administratively shut down, being independent of any hardware failures or link failures, being able to assign any IP address regardless of subnetting constraints, etc. Loopback interfaces are usually numbered from zero (e.g., loopback0) upwards on routers. Loopback interfaces can also be created on PCs or servers for testing or configuration purposes using special IP addresses reserved for loopback testing (e.g., 127.x.x.x for IPv4 or ::1 for IPv6). Loopback interfaces are also known as virtual interfaces or dummy interfaces . Loopback interface state Loopback interface state refers to whether a loopback interface is up or down on a router . A loopback interface state can be either administratively controlled (by using commands such as no shutdown or shutdown ) or automatically determined by routing protocols (by using commands such as passive-interface or ip ospf network point-to-point ). A loopback interface state affects how routing protocols use the IP address assigned to the loopback interface for neighbor discovery , router ID selection , route advertisement , etc . A loopback interface state can also affect how other devices can access or ping the loopback interface . A loopback interface state can be checked by using commands such as show ip interfacebrief or show ip ospf neighbor . is independent of any physical interface and reduces routing updates.

The loopback interface state is independent of any physical interface because it does not depend on any hardware or link status. This means that the loopback interface state will always be up unless it is manually shut down by an administrator. This also means that the loopback interface state will not change due to any physical failures or link failures that may affect other interfaces on the router.

The loopback interface state reduces routing updates because it provides a stable router ID for OSPF that does not change due to any physical failures or link failures that may affect other interfaces on the router. This means that OSPF will not have to re-elect DRs Designated Routers (DRs) Designated Routers (DRs) are routers that are elected by OSPF routers in a broadcast or non-broadcast multi-access (NBMA) network to act as leaders and coordinators of OSPF operations in that network. DRs are responsible for generating link-state advertisements (LSAs) for the entire network segment, maintaining adjacencies with all other routers in the segment, and exchanging routing information with other DRs in different segments through backup designated routers (BDRs). DRs are elected based on their router priority values and router IDs . The highest priority router becomes the DR and the second highest priority router becomes the BDR . If there is a tie in priority values , then the highest router ID wins . DRs can be manually configured by setting the router priority value to 0 (which means ineligible) or 255 (which means always eligible) on specific interfaces . DRs can also be influenced by using commands such as ip ospf priority , ip ospf dr-delay , ip ospf network point-to-multipoint , etc . DRs can be verified by using commands such as show ip ospf neighbor , show ip ospf interface , show ip ospf database , etc . , recalculate SPT Shortest Path Tree (SPT) Shortest Path Tree (SPT) is a data structure that represents the shortest paths from a source node to all other nodes in a graph or network . SPT is used by link-state routing protocols such as OSPF and IS-IS to compute optimal routes based on link costs . SPT is built using Dijkstra’s algorithm , which starts from the source node and iteratively adds nodes with the lowest cost paths to the tree until all nodes are included . SPT can be represented by a set of pointers from each node to its parent node in the tree , or by a set of next-hop addresses from each node to its destination node in the network . SPT can be updated by adding or removing nodes or links , or by changing link costs . SPT can be verified by using commands such as show ip route , show ip ospf database , show clns route , show clns database , etc . , or send LSAs Link-State Advertisements (LSAs) Link-State Advertisements (LSAs) are packets that contain information about the state and cost of links in a network segment . LSAs are generated and flooded by link-state routing protocols such as OSPF and IS-IS to exchange routing information with other routers in the same area or level . LSAs are used to build link-state databases (LSDBs) on each router , which store the complete topology of the network segment . LSAs are also used to compute shortest path trees (SPTs) on each router , which determine the optimal routes to all destinations in the network . LSAs have different types depending on their origin and scope , such as router LSAs , network LSAs , summary LSAs , external LSAs , etc . LSAs have different formats depending ontheir type and protocol version , but they usually contain fields such as LSA header , LSA type , LSA length , LSA age , LSA sequence number , LSA checksum , LSA body , etc . LSAs can be verified by using commands such as show ip ospf database , show clns database , debug ip ospf hello , debug clns hello , etc . due to changes in router IDs.

The other options are not reasons because:

• The IP address associated with the loopback interface is non-routable and prevents loops: This option is false because the IP address associated with the loopback interface is routable and does not prevent loops. The IP address associated with the loopback interface can be any valid IP address that belongs to an existing subnet or a new subnet created specifically for loopbacks. The IP address associated with the loopback interface does not prevent loops because loops are caused by misconfigurations or failures in routing protocols or devices, not by IP addresses.
• The loopback interface state is dependent on the management interface state and reduces routing updates: This option is false because

the loopback interface state is independent of any physical interface state, including the management interface state Management interface Management interface is an interface on a device that provides access to management functions such as configuration, monitoring, troubleshooting, etc . Management interfaces can be physical ports such as console ports, Ethernet ports, USB ports, etc., or virtual ports such as Telnet sessions, SSH sessions, web sessions, etc . Management interfaces can use different protocols such as CLI Command-Line Interface (CLI) Command-Line Interface (CLI) is an interactive text-based user interface that allows users to communicate with devices using commands typed on a keyboard . CLI is one of the methods for accessing management functions on devices such as routers, switches, firewalls, servers, etc . CLI can use different protocols such as console port serial communication protocol Serial communication protocol Serial communication protocol is a method of transmitting data between devices using serial ports and cables . Serial communication protocol uses binary signals that represent bits (0s and 1s) and sends them one after another over a single wire . Serial communication protocol has advantages such as simplicity, low cost, long

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

If the AP has internet access but does not receive its configuration from Aruba Central, one possible reason is that the AP does not have a license assigned in Aruba Central. A license is required for each AP to be managed by Aruba Central. References:https://www.arubanetworks.com/techdocs/Central/2.5.2-GA/HTML_frameset.htm#GUID-8F0E7E8B-0F4B-4A3C-AE7F-0F1B5A7F9C5D.html

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

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

a) Alerts on config changes via email - Foundation b) Group-based firmware compliance - Foundation c) Heat maps of deployed APs - Advanced d) Live upgrades of an AOS10 cluster - Advanced

According to the Aruba Central Licensing Guide1, the Foundation License provides basic device management features such as configuration, monitoring, alerts, reports, firmware management, etc. The Advanced License provides additional features such as AI insights, WLAN services, NetConductor Fabric, heat maps, live upgrades, etc.

https://www.arubanetworks.com/techdocs/central/2.5.3/content/pdfs/licensing-guide.pdf

OAlOps is a feature of Aruba Central that uses artificial intelligence and machine learning to identify recommended steps to resolve network health issues and allows you to share detailed information with support personnel. OAlOps provides insights into network performance, root cause analysis, anomaly detection, proactive alerts, and automated remediation actions.OAlOps also integrates with Aruba User Experience Insight (UXI) sensors to measure and improve user experience across wired and wireless networks. References:https://www.arubanetworks.com/assets/ds/DS_ArubaCentral.pdf

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

Layer: 1) Physical layer Phase of Message Processing: d) Organize the data into bits

Layer: 2) Data Link layer Phase of Message Processing: c) Organize the data into frames

Layer: 3) Network layer Phase of Message Processing: b) Organize the data into packets

Layer: 4) Transport layer Phase of Message Processing: a) Organize the data into segments

The OSI model divides the networking process into seven layers, each representing a different step of the transmission chain. Each layer has its own function and is responsible for well-defined tasks. User data passes sequentially from the highest layer down through the lower layers until the device transmits it externally. The lowest layer, the physical layer, converts the data into bits that can be sent over a physical medium. The second layer, the data link layer, organizes the bits into frames that can be transmitted over a link between two nodes. The third layer, the network layer, organizes the frames into packets that can be routed across a network of nodes. The fourth layer, the transport layer, organizes the packets into segments that can provide reliable and error-free communication between two end points12. References: 1 https://www.linode.com/docs/guides/introduction-to-osi-networking-model/  2 https://en.wikipedia.org/wiki/OSI_model

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

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

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 data transmission, 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