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

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

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.

A flashing amber global status indicator LED on an Aruba CX6200M switch typically indicates that the switch has encountered a fault, but it is recoverable. This LED behavior serves as an alert to the network administrator that an issue needs to be addressed, but it does not necessarily mean that the switch is inoperable.

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

Aruba's Captive Portal primarily uses Layer 3 authentication, which operates at the network layer. When a user connects to a network with a Captive Portal, they are redirected to a web page for authentication. This process involves the user entering credentials or accepting terms and conditions through a web interface before gaining full access to the network. The Captive Portal intercepts the user's web traffic at Layer 3, requiring them to authenticate before proceeding, which is why it's considered a form of Layer 3 authentication.

On an Aruba CX 6300M switch, routing between Switch Virtual Interfaces (SVIs) is enabled by default. Therefore, traffic between SVIs, like 120 and 130, can be routed internally without the need for additional configuration such as route leaking or static routes, as long as there is no 'no routing' configuration present on the SVIs.

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.

When a client connects to an Aruba AP in tunnel mode and is assigned to a VLAN based on the client's MAC address, this indicates a Dynamic VLAN assignment. The VLAN is determined dynamically at the time of authentication based on the client's credentials or attributes, such as its MAC address.

For an 80m distance between wiring closets, using SFP+ transceivers is appropriate as they can support longer distances than standard copper interfaces. Ports 1/1/51 and 1/1/52 are typically reserved for uplinks on Aruba CX 6200F 48G switches and can support SFP+ transceivers, making them suitable for a redundant link-aggregation port configuration.

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.

Strict queuing is the best scheduling technology for ensuring that voice traffic, which is sensitive to latency, is prioritized above other types of traffic. This method ensures that voice traffic is sent first before other queued traffic, effectively reducing the possibility of delay.

The RADIUS message that you should look for to ensure a successful connection via 802.1X is Access-Accept. This message indicates that the RADIUS server has authenticated and authorized the supplicant (the device that wants to access the network) and has granted it access to the network resources. The Access-Accept message may also contain additional attributes such as VLAN ID, session timeout, or filter ID that specify how the authenticator (the device that controls access to the network, such as a switch) should treat the supplicant’s traffic.

The other options are not RADIUS messages because:

Authorized: This is not a RADIUS message, but a state that indicates that a port on an authenticator is allowed to pass traffic from a supplicant after successful authentication and authorization.

Success: This is not a RADIUS message, but a status that indicates that an 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). exchange has completed successfully between a supplicant and an authentication server.

Authenticated: This is not a RADIUS message, but a state that indicates that a port on an authenticator has received an EAP-Success message from an authentication server after successful authentication of a supplicant.

References: https://en.wikipedia.org/wiki/RADIUS#Access-Accept https://www.cisco.com/c/en/us/support/docs/security-vpn/remote-authentication-dial-user-service-radius/13838-10.html https://en.wikipedia.org/wiki/IEEE_802.1X#Port-based_network_access_control https://en.wikipedia.org/wiki/Extensible_Authentication_Protocol#EAP_exchange

The part of WPA Key Hierarchy that is used to encrypt and/or decrypt data is Pairwise Temporal Key (PTK). PTK is a key that is derived from 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 , ANonce Authenticator Nonce (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 subkey that is specifically used for data encryption is TK Temporal Key (TK). TK is also known as Pairwise Transient Key (PTK). TK changes periodically during communication based on time or number of packets transmitted.

The other options are not part of WPA Key Hierarchy because:

PMK: PMK is not part of WPA Key Hierarchy, but rather an input for deriving PTK.

KCK: KCK is part of WPA Key Hierarchy, but it is not used for data encryption, but rather for message integrity check.

Nonce: Nonce is not part of WPA Key Hierarchy, but rather an input for deriving 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

Add certificates to Android devices with the Aruba Onboard Application in the Google Play store that will be used for wireless authentication A) ClearPass Policy Manager

Authenticate users on corporate-owned Chromebook devices using 802.1X and context gathered from the network devices that they log into B) Cloud Authentication and Policy

Leverage unbound Mum Pre-Shared Keys (MPSK) managed by Aruoa Central to the end-users and client devices B) Cloud Authentication and Policy

Validate devices exist in a Mobile Device Management (MDM) database before authenticating BYOD users with corporate Active Directory using certificates A) ClearPass Policy Manager

https://www.arubanetworks.com/techdocs/ClearPass/6.11/PolicyManager/Content/CPPM_UserGuide/About%20ClearPass/About_ClearPass.htm

https://www.arubanetworks.com/products/security/network-access-control/

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 Authenticator Nonce (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 ExtensibleAuthentication 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

When a wireless client’s countdown timer (also known as a backoff timer) reaches zero during contention-based access periods, and it receives a Transmit Opportunity (TXOP), it has the right to transmit its data frames on the medium. After sending the data frames, it expects an acknowledgment (ACK) from the Access Point (AP) to ensure the frames were received successfully.

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.

LLDP (Link Layer Discovery Protocol) is commonly used by network devices, including wireless access points, to negotiate PoE (Power over Ethernet) power levels with the switch they are connected to. This allows the access point to communicate its power requirements to ensure it receives the necessary power for optimal operation.

The Address Resolution Protocol (ARP) is used to map layer-3 IP addresses to layer-2 MAC addresses. When a device on a network wants to communicate with another device, it uses ARP to find the MAC address that corresponds to the IP address it wishes to communicate with, allowing it to construct a frame for the local network.

Aruba AirMatch is a feature that optimizes RF Radio Frequency. RF is any frequency within the electromagnetic spectrum associated with radio wave propagation. When an RF current is supplied to an antenna, an electromagnetic field is created that then is able to propagate through space. performance and user experience by using machine learning algorithms and historical data to dynamically adjust AP power levels, channel assignments, and channel width. AirMatch performs live firmware upgrades on Aruba APs by partitioning all the APs based on RF neighborhood data and minimizing the impact on clients. AirMatch uses a rolling upgrade process that upgrades one partition at a time while ensuring that adjacent partitions are not upgraded simultaneously. References: https://www.arubanetworks.com/assets/ds/DS_AirMatch.pdf https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/arm/AirMatch.htm

dBm is a unit of power that measures the ratio of a given power level to 1 mW. The formula to convert dBm to mW is: P(mW) = 1mW * 10^(P(dBm)/10). Therefore, -20 dBm corresponds to 0.01 mW, as follows: P(mW) = 1mW * 10^(-20/10) = 0.01 mW References:https://www.rapidtables.com/convert/power/dBm_to_mW.html

The dBm is a logarithmic unit of power relative to 1 milliwatt (mW). -20 dBm means that the signal strength is 20 decibels lower than 1 mW. In terms of mW, this is 0.01 mW. Each 10 dB decrease represents a tenfold decrease in power. Therefore, -20 dBm is10−210−2or 0.01 mW.

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

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

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

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.

The administrative distance is used as a trust rating for route entries (B). It is a metric used by routers to select the best path when there are two or more different routes to the same destination from two different routing protocols. The lower the administrative distance value, the more trustworthy the source of the route. For example, a directly connected network has an administrative distance of 0 because it is the most trusted source of routing information. In contrast, routes learned from different routing protocols have higher administrative distances, reflecting their relative trustworthiness.

The way that STP Spanning Tree Protocol. STP is a network protocol that ensures a loop-free topology for any bridged Ethernet local area network by preventing redundant paths between switches or bridges from creating loops that cause broadcast storms, multiple frame transmission, and MAC table instability. STP creates a logical tree structure that spans all of the switches in an extended network and blocks any redundant links that are not part of the tree from forwarding data packets3. will forward or discard traffic on these ports is as follows:

STP will elect a root bridge among the two switches based on their bridge IDs, which are composed of a priority value and a MAC address. The switch with the lower bridge ID will become the root bridge and will forward traffic on all its ports.

STP will assign a role and a state to each port on both switches based on their port IDs, which are composed of a priority value and a port number. The port with the lower port ID will become the designated port and will forward traffic, while the port with the higher port ID will become the alternate port and will discard traffic.

In this scenario, since both switches have two cables connected between ports 1/1/1 and 1/1/2, there will be two possible paths between them, creating a loop. To prevent this loop, STP will block one of these paths by discarding traffic on one of the ports on each switch.

Assuming that both switches have the same priority value (default is 32768), the switch with the lower MAC address will have the lower bridge ID and will become the root bridge. The root bridge will forward traffic on both ports 1/1/1 and 1/1/2.

Assuming that both ports have the same priority value (default is 128), port 1/1/1 will have a lower port ID than port 1/1/2 on both switches because it has a lower port number. Port 1/1/1 will become the designated port and will forward traffic, while port 1/1/2 will become the alternate port and will discard traffic.

Therefore, the switch with the lower MAC address will discard traffic on one port (port 1/1/2), while the switch with the higher MAC address will also discard traffic on one port (port 1/1/2).

References: 3 https://en.wikipedia.org/wiki/Spanning_Tree_Protocol

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.