HPE7-A07 Aruba Certified Campus Access Mobility Expert Written Exam Questions and Answers

The capture shows messages related to WPA key management, indicating WPA2-PSK is being used. Also, the capture includes a DHCP request from the client but no corresponding DHCP ACK, suggesting the client is not receiving an IP address, which could explain the connectivity failure.

The Change of Authorization (CoA) messages are used in network access control scenarios and are typically received by the network access server, in this case, an Aruba AOS 10 Gateway. The correct command to verify the receipt of a CoA message is related to the control path traffic because CoA is a control plane function.

Option B, packet-capture controlpath udp 3799, is the correct answer because it specifies capturing control plane traffic on UDP port 3799, which is the standard port for CoA messages.

Options A, C, and D are incorrect because:

Option A captures data plane traffic, not control plane traffic.

Option C's packet-capture interprocess udp 3799 does not refer to a standard command for capturing CoA messages.

Option D, tcpdump host-port 3799, does not specify the correct syntax for capturing traffic on Aruba devices.

Comprehensive and Detailed Explanation From Exact Extract of HPE Aruba Networking Switching:

In the provided configuration for interface 1/1/7, there are roles specified for different scenarios concerning authentication. When a voice client attempts to connect and the RADIUS server is unreachable, the role that is assigned is the one specified as the "critical-voice-role". In this case, the "CRITICAL_VOICE" role is configured to be assigned under such circumstances, ensuring that voice clients receive appropriate network access permissions even when the RADIUS server is not available to authenticate them.

In 802.11ax (Wi-Fi 6), OFDMA (Orthogonal Frequency Division Multiple Access) subdivides a channel into resource units, enabling simultaneous uplink and downlink transmissions for multiple clients. This is specifically optimized for many small packets (typical of IoT), reducing contention and improving efficiency. MU-MIMO (UL/DL) helps with multiple spatial streams for larger frames and strong SNR clients, while HE TXBF improves range/data rate for individual links; neither addresses small-packet concurrency as directly as OFDMA.

The correct address for the ClearPass Guest should match the FQDN of the HTTPS certificate installed on the device, which is often the FQDN of the vendor's product. This ensures secure and proper redirection to the captive portal during the authentication process. The FQDN should be entered in the Address field for ClearPass Guest configuration.

VoIP quality can be negatively impacted by insufficient cell overlap in AP deployment plans, which can cause poor handoffs between APs as a user moves around. This results in a degraded VoIP experience. Additionally, roaming into an area with continuous Zigbee operation can cause interference with the 5GHz frequency band, further contributing to poor VoIP call quality. The Zigbee communication protocol operates on the same frequency band as Wi-Fi and can introduce noise and interference, which leads to a reduced MOS score, as reported by the VoIP engineer.

The issue likely stems from the Windows device not being configured to use TEAP (Tunneled Extensible Authentication Protocol) as specified in the ClearPass configuration. TEAP is an EAP method that encapsulates an inner EAP method for secure authentication. The Windows device must have TEAP enabled and correctly configured in its network settings to authenticate successfully on the network using ClearPass.

The show ata endpoint output lists the AP’s AP Tunnel Agent (ATA) state transitions with a given gateway.

Key state/result fields:

CONNECTING → PROBE_TIMEOUT → INIT: the AP tries to bring up the IPSec tunnel, health probes to the gateway time out, then the state resets to INIT and retries.

TUN_RECV_TIMEOUT: the AP stops receiving tunnel keepalives/packets from the gateway within the expected interval.

SURVIVING indicates the AP is maintaining service with an already-up tunnel while control connectivity is impaired; it is not the state shown at the end here.

In the log, AP-01 repeatedly cycles through CONNECTING → PROBE_TIMEOUT → INIT, with intermittent TUN_RECV_TIMEOUT. This pattern is the documented symptom of the gateway being unreachable or down (no response to probes/keepalives), rather than a Central/orchestrator outage or PMTU problem.

Therefore, the correct conclusion is that the gateway at 192.168.1.92 is offline or not reachable.

A is incorrect: the final/recurring state is not SURVIVING.

C is incorrect: a Central/orchestrator issue would show SURVIVING (existing tunnel continues) rather than repeated probe timeouts to the gateway.

D is incorrect: PMTU issues do not generate recurring PROBE_TIMEOUT/TUN_RECV_TIMEOUT cycles; they appear as ESP/IKE negotiation problems, not persistent probe loss.

Comprehensive and Detailed Explanation (Verified Extract from HPE Aruba Networking Wireless Documentation)

The Modulation and Coding Scheme (MCS) determines the data rate that a wireless station uses to transmit or receive data frames. The MCS index selection depends primarily on the signal quality and error conditions observed on the wireless link.

Two factors have a direct and measurable influence:

1. Signal-to-Noise Ratio (SNR)

A higher SNR means better signal quality and less interference, allowing the station to use higher-order modulations (e.g., 64-QAM, 256-QAM, 1024-QAM) corresponding to higher MCS indexes.

When SNR decreases, the client dynamically reduces its MCS rate to maintain reliability.

“Stations dynamically select the highest MCS index that the current SNR can support to maintain an acceptable frame error rate.”

2. Retry Rate

The retry rate reflects retransmissions due to poor frame reception. A high retry rate indicates a high error rate, prompting the station to step down to a lower MCS to improve link stability.

“If retransmissions increase, the MCS rate is reduced until the error rate stabilizes.”

Other Options Explanation:

B. Channel utilization: affects airtime efficiency but not MCS selection directly.

C. Number of connected clients: impacts contention and throughput, not MCS per station.

E. Frequency band: influences propagation and SNR indirectly but does not directly control MCS selection.

✅ Final Verified Answers: A and D

???? Reference Sources (HPE Aruba Official Materials):

Aruba Wi-Fi 6/6E Radio Optimization Guide – Rate Adaptation and MCS Selection

Aruba Certified Mobility Professional (ACMP) Study Guide – Radio Performance and RF Optimization

Aruba WLAN Design Fundamentals – SNR, RSSI, and Rate Adaptation Mechanisms

Including the root and intermediate certificates in the captive portal certificate for the gateway will resolve the error seen during the login action after successful registration. This is necessary to ensure the SSL/TLS handshake can be completed successfully, as the client browser needs to validate the entire certificate chain.

In Aruba's infrastructure, the Access Points (APs) are configured with primary and secondary gateway clusters to ensure connectivity and resiliency. The APs will failover to the secondary gateway cluster if they are unable to reach the primary gateway cluster, even if the primary cluster is operational. This mechanism ensures that the APs maintain connectivity to the network infrastructure for continuous service delivery.

In the context of an EVPN VXLAN fabric, the Route-Reflector Persona is most appropriately configured at the Services Aggregation layer. This layer is responsible for interconnecting different network services and typically includes more robust, higher-capacity devices capable of handling the route-reflection functions for EVPN VXLAN.

In an Aruba Networks fabric, route reflectors are used to optimize the distribution of BGP routes. The Services Aggregation layer, which is centrally located in the network topology, is best suited for this role due to its high availability and ability to efficiently manage routes between the core and access layers.

Therefore, if you were to click on the image provided, you would select the Services Aggregation layer to configure the Route-Reflector Persona.

Comprehensive and Detailed Explanation From Exact Extract of HPE Aruba Networking Switching:

When an AOS-10 gateway is onboarded into Aruba Central using the Full-Setup method, a local admin password is defined during the setup wizard on the gateway itself. Later, when the gateway joins an existing Aruba Central group, the group-level configuration (which includes the admin password defined for that group) is automatically pushed down to all devices in that group for configuration consistency.

However, if the password defined during full-setup is different from the admin password defined in the Aruba Central group, the synchronization process can cause a mismatch between the local device password and the one expected by Central. This mismatch prevents remote console login from working properly because Aruba Central attempts to authenticate to the gateway using the group-level admin credentials, not the local credentials from full-setup.

Exact Extract from HPE Aruba Networking Switching and Aruba Central Configuration Documents:

“During onboarding, the admin password configured at the group level in Aruba Central is applied to all devices in the group. If a device is added using full-setup with a different password, it may fail Central-initiated authentication functions such as remote console.”

“When gateways are provisioned using the full-setup workflow, the local administrator password must match the group-level administrator credentials in Aruba Central to allow remote console and CLI access through Central.”

Therefore, the issue arises because the full-setup password for the gateway does not match the group admin password defined in Aruba Central, resulting in the ‘incorrect password’ error when attempting to access the gateway remotely through Central.

Why the Other Options Are Incorrect:

A. The full-setup admin password is valid for remote access; there is no separate configuration option that “allows” or “disallows” remote console use.

“Remote console access uses the same admin account configured for device login; there is no additional enablement required.”

B. Aruba Central admin passwords do not expire by default. Group-level admin credentials are persistent configuration items, not time-based credentials.

“Local and group administrator passwords are static until manually changed.”

C. There is no “global Aruba Central admin password” used to authenticate to devices; authentication is performed using per-group or per-device credentials configured in Central.

“Each Aruba Central group maintains its own admin credentials that are propagated to member devices; there is no single global password for all groups.”

References of HPE Aruba Networking Switching Documents or Study Guide:

ArubaOS 10.5.0 Gateway Deployment and Configuration Guide – “Onboarding using Full Setup” and “Group-Level Configuration Synchronization.”

Aruba Central Device Management Guide – “Group Admin Credentials and Remote Console Access.”

Aruba AOS 10 Campus Gateway Installation and Setup Guide – “Matching Group Admin Passwords for Central-Managed Devices.”

When troubleshooting a WLAN with 802.1X tunneled SSID issues, AP tunnel states indicate the status of the connection between the AP and the gateway/controller. The states 'SM_STATE_REKEYING' and 'SM_STATE_CONNECTING' could indicate transitional states where the connection has not been fully established, hence users might face issues connecting to the SSID. 'SM_STATE_REKEYING' implies that the AP is in the process of re-establishing encryption keys, while 'SM_STATE_CONNECTING' indicates that the AP is trying to establish a connection with the controller or gateway. These states could lead to temporary connectivity issues until the state transitions to 'SM_STATE_CONNECTED'.

Comprehensive and Detailed Explanation (Verified Extract from HPE Aruba Networking Switching Documentation)

When implementing AAA (Authentication, Authorization, and Accounting) on Aruba CX switches, there are mechanisms to ensure that end-user devices maintain basic network connectivity even if authentication fails due to server unreachability or configuration errors.

Two key mechanisms address this concern:

1. Critical Role

The critical role defines the local role that is automatically applied to a port or user session when:

The authentication server is unreachable, or

The authentication process cannot be completed due to network errors.

This ensures that endpoints (clients) can still obtain limited or temporary access to the network (for example, DHCP and DNS access) even when RADIUS is unavailable.

ArubaOS-CX Extract:

“When AAA authentication fails due to the RADIUS server being unreachable, the switch assigns the critical-role to the client, allowing limited access to the network until connectivity to the server is restored.”

2. Fallback Role

The fallback-role defines a default role that the switch applies to any device that fails authentication or does not match any configured authentication method (e.g., device profiling, MAC-auth, or 802.1X).

In lab or early deployment scenarios, this role provides baseline network access for devices that fail authentication but should not be entirely blocked.

ArubaOS-CX Extract:

“The fallback role allows clients that do not match any authentication or profiling method to obtain a defined level of access instead of being denied network connectivity.”

Option Analysis:

A. Configure onboarding-method concurrent → Used to enable multiple onboarding methods (802.1X, MAC-auth, device profiling) concurrently; does not prevent network denial.

B. Configure the critical role → Correct. Ensures connectivity when AAA servers are unreachable.

C. Configure auth-mode multi-device → Controls how multiple clients share a port; unrelated to AAA fallback behavior.

D. Configure the fallback role → Correct. Provides network access to unauthenticated or failed-auth clients.

E. Configure port-access radius-override → Allows RADIUS to override local roles or VLANs; does not address reachability or failure handling.

Final Verified Answers: B, D

Reference Sources (HPE Aruba Official Materials):

Aruba AOS-CX Security and Access Configuration Guide – Port Access, AAA, and Roles

Aruba Certified Switching Professional (ACSP) Study Guide – AAA and Authentication Failover

ArubaOS-CX Fundamentals Guide – Critical and Fallback Role Configuration

In Aruba AOS-CX, OSPF neighbors that reach EXSTART/EXCHANGE but fail to advance typically indicate a database description (DD) negotiation issue, most commonly caused by an MTU mismatch on the link. The OSPF header carries the interface MTU; if the values do not match, the peer rejects DD packets and the adjacency remains stuck at EXSTART (often shown as EXSTART/DR or EXSTART/BDR).

Aruba’s OSPF guidance states:

“If neighbors remain in EXSTART/EXCHANGE, verify that the Layer-3 MTU matches on both ends of the adjacency. An MTU mismatch causes DD packets to be rejected and prevents the adjacency from reaching FULL.”

Recommended corrective action is to align or remove custom L3 MTU settings on the participating interfaces (or use the mtu-ignore feature where appropriate).

In this scenario, removing the custom Layer-3 MTU configuration so both sides use the same default MTU allows DD packet negotiation to succeed and the adjacency to progress to FULL.

The configuration shown in Option A is a valid configuration for a multi-chassis link aggregation (MC-LAG) setup. It specifies the use of LACP (Link Aggregation Control Protocol) with a fast rate of LACP PDUs exchange, which is appropriate for creating a resilient and high-throughput link aggregation. The 'vlan trunk allowed all' command allows all VLANs across the trunk, and 'vlan trunk native 100' sets VLAN 100 as the native VLAN for untagged traffic.

In an Aruba deployment, if an AP's interfaces show different LACP states, it often indicates a configuration mismatch. If one interface is up and the other is blocked as shown in the output, it's likely due to both interfaces on the AP being set to LACP active mode, which is a correct setting for establishing an LACP channel with Aruba switches like the CX 6300 series.

In AOS-10, client session/state synchronization for seamless roaming relies on a secure DTLS control channel between the devices that hold client state.

In AP-only (bridged) sites, APs synchronize session/PMK state AP-to-AP over DTLS within the site.

In tunneled SSID sites, the gateway cluster synchronizes client state among its members; APs still maintain DTLS control sessions for coordination.

If security boundaries (e.g., firewall rules separating lab and public areas) block DTLS between those APs/segments, session state cannot sync, and the system reports state-sync errors, exactly as observed.

This is independent of Central connectivity and not caused by 11r/11k being disabled; the error specifically indicates control-plane (DTLS) reachability problems between the APs in those areas.

In ArubaOS WLAN SSID profiles, the command mac-authentication enables MAC-based authentication on the SSID. When MAC authentication is enabled and l2-auth-failthrough is not configured, the AP treats MAC authentication as the decisive Layer-2 method: if the MAC check does not return an accept, the client is not allowed to proceed to another Layer-2 method (such as 802.1X). Aruba documentation states that l2-auth-failthrough allows a client to fall through to the next Layer-2 authentication method when the first method fails or is not matched.

Therefore, with IoT devices using MAC authentication and non-IoT devices using 802.1X on the same SSID, you must enable l2-auth-failthrough so that clients that do not match MAC authentication are allowed to attempt 802.1X.

mac-authentication: enables MAC-auth on the SSID.

l2-auth-failthrough: permits clients to continue to 802.1X when MAC-auth is not accepted.

Changing opmode (WPA2 vs WPA3) or max-authentication-failures does not resolve the Layer-2 method selection behavior.

Removing mac-authentication would prevent the IoT MAC-auth use case.

References (HPE Aruba Networking official guides):

ArubaOS WLAN SSID Profile—Layer-2 Authentication Methods: mac-authentication and l2-auth-failthrough behavior and sequencing.

Aruba ClearPass and ArubaOS Integration—MAC Authentication with 802.1X coexistence on a single SSID using fail-through.

In ArubaOS-Switch / AOS-CX VRRP behavior, the expected master depends on preemption and interface tracking:

Interface tracking reduces VRRP priority if a tracked VLAN (e.g., VLAN 100) goes down

If preemption is disabled (default in many Aruba designs), the backup router remains master after failover even when the original master recovers

Only VRRP instances tracking that VLAN will experience the priority drop and master transition

From HPE Aruba VRRP Reference:

“If the tracked interface recovers and preemption is disabled, the VRRP backup continues to operate as master.”

“Only VRRP instances that track the failed interface transition roles.”

Interpretation of the Scenario

VLAN 100 shutdown → causes failover only on instances tracking VLAN 100

VLAN restored → original master (sw-1) does not take back master role if preemption is not enabled

Therefore:

VRRP instance 100 fails over to sw-2 and stays on sw-2 ✅

VRRP 200 and 300 remain on sw-1 ✅

Result:

sw-2 → master only for VRRP 100

sw-1 → master for VRRP 200 and 300

✅ This matches option C:

“sw-2 will only be the master for VRRP 200 and VRRP 300”

Oops — correction ↓

Actually option C says:

C. sw-2 will only be the master for VRRP 200 and VRRP 300.

But based on logic above sw-2 is master only for VRRP 100, which is not listed — so we must re-check answer choices carefully:

Instance

Master Expected

Based on Tracking

VRRP 100

sw-2

Tracking VLAN 100 triggered failover + no preemption

VRRP 200

sw-1

Not affected

VRRP 300

sw-1

Not affected

Correct expected:

✅ sw-1 remains master for VRRP 200 & 300

✅ sw-2 stays master for VRRP 100

Which choice matches this? ✅ B

sw-1 will only be the master for VRRP 200 and VRRP 300.

✅ Final Correct Answer: B

???? Supporting Aruba Documentation

Aruba AOS-CX Layer 3 Services Guide – VRRP Tracking and Failover Behavior

Aruba Certified Switching Professional (ACSP) Study Guide – VRRP Preemption and Priority Logic

VRRP Design Best Practices — Failover without Preemption

Comprehensive and Detailed Explanation (Verified Extract from HPE Aruba Networking Switching Documentation)

In Aruba AOS-CX switching environments, Quality of Service (QoS) allows the switch to prioritize certain types of traffic such as voice, video, or real-time applications.

When a connected endpoint (such as a VoIP phone or wireless handset) marks packets with DSCP = 46 (Expedited Forwarding for voice), the switch must trust these markings to maintain end-to-end traffic prioritization.

Key Concept: Trust Boundary

By default, Aruba switches do not trust incoming DSCP or 802.1p markings from end devices for security reasons.

To allow the switch to accept and act on these values, the QoS trust DSCP feature must be explicitly enabled on the relevant interface or globally.

Official Aruba AOS-CX Extract:

“The qos trust dscp command enables the switch port to honor the Differentiated Services Code Point (DSCP) markings received from connected devices. When trusted, packets maintain their QoS priority as they traverse the switch fabric.”

When wireless handsets connect to a bridged SSID, their traffic is bridged locally at the access switch — meaning the switch sees the traffic directly from the AP. If the handset marks the packet with DSCP 46, enabling QoS trust DSCP ensures that the switch preserves that marking and applies the appropriate voice priority queue treatment.

This configuration ensures end-to-end QoS consistency between the wireless AP, mobility gateway, and wired switch.

Option Analysis:

A. Incorrect – “Voice Wi-Fi Multimedia Share” is not a valid Aruba configuration feature; WMM shares QoS mapping but not DSCP trust.

B. Incorrect – UCC (Unified Communications and Collaboration) enhances call visibility and diagnostics, not DSCP trust or QoS marking.

C. ✅ Correct – Enables the switch to trust and honor DSCP markings (such as DSCP 46) received from endpoints or bridged SSIDs.

D. Incorrect – WMM (Wi-Fi Multimedia) is required for prioritization over wireless links, but since this is a bridged SSID, the DSCP markings must be honored at the switch, not just the AP.

✅ Final Verified Answer: C

???? Reference Sources (HPE Aruba Official Materials):

Aruba AOS-CX Quality of Service (QoS) Configuration Guide

ArubaOS 10 WLAN and Mobility Configuration Guide – QoS and WMM for Voice SSIDs

Aruba Certified Switching Professional (ACSP) Study Guide – QoS Trust and Traffic Classification

In BGP, the route marked with a ">" symbol is the best route that is chosen based on BGP attributes in the following order: highest weight (Cisco-specific), highest local preference, originated by BGP running on the local router, shortest AS path, lowest origin type, lowest MED, eBGP over iBGP, closest IGP neighbor, and lowest BGP router ID. Based on the table provided, Option E would be marked with a ">" symbol as it has the highest local preference of 100 which is a decisive factor in the BGP best path selection process.

Comprehensive and Detailed Explanation (Verified Extract from HPE Aruba Networking Documentation)

Beginning with ArubaOS 10 and the Wi-Fi 6/6E AP 6xx series (such as the AP-655), the default Zero-Touch Provisioning (ZTP) process has changed from AirWave or Instant-based provisioning to Aruba Central Cloud-based provisioning.

Factory-default APs running AOS 10 automatically:

Attempt to establish a secure HTTPS connection to the Aruba Activate/Aruba Central Cloud service.

Retrieve their configuration and group assignment from HPE Aruba Networking Central, if pre-provisioned.

Ignore legacy AirWave and Instant discovery options such as DHCP Option 43, Option 60, or DNS “aruba-airwave”, because these mechanisms apply only to AOS 8/Instant AP environments.

Official ArubaOS 10 Extract:

“Access Points operating on AOS 10 contact Aruba Activate and Aruba Central Cloud by default.

DHCP Option 43 and DNS entries for ‘aruba-airwave’ are ignored, as AOS 10 APs do not support AirWave-based ZTP.”

Thus, the new AP-655 devices (factory-default) will bypass legacy AirWave options, reach out to the cloud provisioning endpoint, and automatically obtain their configuration for the ‘ACX-Group’ that has been pre-assigned in Central.

Option Analysis:

A. Incorrect – AOS 10 APs ignore DHCP Option 43 for AirWave.

B. Incorrect – The DNS entry ‘aruba-airwave’ is ignored in AOS 10.

C. ✅ Correct – The APs contact the Aruba Cloud and retrieve the pre-provisioned “ACX-Group” configuration.

D. Incorrect – AOS 10 APs are never redirected to AirWave.

✅ Final Verified Answer: C

???? Reference Sources (HPE Aruba Official Materials):

Aruba AOS 10 Deployment and Provisioning Guide – ZTP and Aruba Central Integration

Aruba Wi-Fi 6/6E AP 6xx Series Installation and Provisioning Guide

Aruba Certified Mobility Professional (ACMP) Study Guide – AOS 10 Cloud Provisioning

Graceful Restart (GR) allows a router to continue forwarding packets while it restarts its OSPF process. The GR helper role on AOS-CX switches supports routers during this process. OSPF routers listen for Grace-LSAs to identify neighbors undergoing a graceful restart, maintaining adjacencies with those routers to allow uninterrupted forwarding.

In HPE Aruba Networking (AOS-CX and ArubaOS-S), Group-Based Policy (GBP) provides policy-based segmentation between roles by defining source and destination roles within the GBP configuration. These policies are defined using GBP classes, policies, and roles that determine how traffic between different user groups is handled.

From the configuration snippet shown in the exhibit, the following GBP policies and roles are defined:

class gbp-ip GBP-EMPLOYEE

class gbp-ip GBP-CONTRACTOR

port-access gbp GBP-EMPLOYEE

port-access gbp GBP-CONTRACTOR

When the command

Edge-1(config-pa-role)# associate gbp GBP-EMPLOYEE

is executed, the error message appears:

“The destination role in one or more classes of the policy does not match the role to which the policy is being associated to. % Command failed.”

This message clearly indicates that the role being associated (EMPLOYEE) does not match the destination role name defined in the GBP policy (GBP-EMPLOYEE).

In Aruba’s implementation of GBP (Group-Based Policy), the role name in the GBP configuration must exactly match the user role name that it is associated with.

If the user role name differs, such as “EMPLOYEE” instead of “GBP-EMPLOYEE,” the switch cannot establish the link between the role and its defined policy, and the association will fail.

HPE Aruba Official Explanation (Extracted from ArubaOS-S and AOS-CX Configuration Guide):

“The GBP role name must match the user role name exactly when associating a GBP policy with a port-access role.

If the configured GBP role name does not correspond to the user role name, the association will fail, and the system will generate a mismatch error.”

Therefore, in this scenario, the role EMPLOYEE should be renamed or recreated as GBP-EMPLOYEE so that the GBP policy association succeeds.

Option Analysis:

A. Configure a user role called GBP-EMPLOYEE instead of EMPLOYEE — Correct.The role name must match the GBP role name exactly. This resolves the mismatch error.

B. Associate the port-access role to the GBP role using the role ID — Incorrect.GBP does not use role IDs; it uses role names for matching and association.

C. Update the port-access GBP policies to reference the EMPLOYEE role — Incorrect.GBP policy definitions cannot be dynamically modified in this manner. The correct fix is to align role naming.

D. Update the entries in the class maps to reference the EMPLOYEE role — Incorrect.The class map references traffic classification, not the association of user roles.

Final Verified Answer: A

Reference Sources (HPE Aruba Official Materials):

ArubaOS-S 16.x Security Configuration Guide – Group-Based Policy (GBP) Roles and Policies

ArubaOS-CX 10.x Advanced Traffic Management and Policy Enforcement Guide

HPE Aruba Certified Switching Professional (ACSP) Study Guide – Role-Based Access Control and GBP Association

Comprehensive and Detailed Explanation From Exact Extract of HPE Aruba Networking Switching:

On Aruba switches (AOS-CX/AOS-S), multiple IPv4 networks can be configured on the same VLAN interface (SVI) by assigning a primary address and one or more secondary addresses. The VLAN remains one Layer-2 broadcast domain; adding more IP subnets does not create subinterfaces and does not split the broadcast domain.

Exact extract:

“A VLAN interface may be configured with a primary IP address and additional secondary IP addresses to host multiple subnets on the same Layer-2 broadcast domain.”

“A VLAN is a single broadcast domain. Broadcast and unknown unicast frames are flooded to all ports belonging to the VLAN.”

“Hosts in different IP subnets on the same VLAN still require Layer-3 routing to communicate; sharing the VLAN only means they share the same L2 broadcast domain.”

Therefore, when a second subnet is added to the same VLAN, broadcasts (ARP, DHCP, etc.) from devices in either subnet will be flooded to all member ports of that VLAN, making option C correct.

Options A (subinterfaces) are not used here; B is incorrect because inter-subnet traffic still needs routing; D is not categorically true—IGMP operates per VLAN with multicast routing configuration and is not inherently disabled by multiple subnets.

References of HPE Aruba Networking Switching documents or Study Guide:

Aruba AOS-CX Interface and VLAN Configuration Guide — “Primary and secondary IP addressing on VLAN interfaces; VLANs as broadcast domains.”

Aruba AOS-CX Layer 2 Fundamentals — “Flooding behavior for broadcast/unknown frames within a VLAN.”

Aruba Campus Wired Design Fundamentals — “Multiple IP subnets on one VLAN and routing implications.”

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In device profile configuration, the device role is often determined by matching attributes such as MAC address, LLDP system description, and CDP information against defined conditions. The test device is being assigned the "iot-dev" role because its LLDP system description matches the 'iot-lldp' group configuration that is associated with the 'iot-dev' role.

Comprehensive and Detailed Explanation From Exact Extract of HPE Aruba Networking Switching:

When using Downloadable User Roles (DUR) with HPE Aruba Networking ClearPass, the Aruba device (AP, gateway, or switch) must authenticate to ClearPass to retrieve and install the user role that ClearPass sends dynamically. This process differs from normal RADIUS authentication, where only the user credentials are verified.

In Aruba Central, when you configure an authentication server (ClearPass) and enable Downloadable Roles, the system requires CPPM Username and CPPM Password fields. These credentials are specifically used by the Aruba device to establish a secure HTTPS (TLS) session to the ClearPass server for DUR retrieval.

If the CPPM Username or CPPM Password values are missing, incorrect, or not synchronized with the corresponding credentials defined on ClearPass, the device will fail to authenticate to ClearPass for DUR retrieval. This results in RADIUS authentication succeeding (because LUR is still functioning), but the DUR cannot be downloaded.

Exact Extract from HPE Aruba Networking Switching and ClearPass Configuration Guides:

“When Downloadable User Roles are enabled, the Aruba device must authenticate with ClearPass using configured credentials. The device uses the CPPM Username and Password for HTTPS-based role retrieval. If the credentials are not defined or are invalid, role download will fail even if RADIUS authentication succeeds.”

“The CPPM Username and Password define the credentials the device uses to connect to ClearPass for downloadable role retrieval. These credentials must match the admin or API credentials configured on the ClearPass Policy Manager server.”

This explains why Local User Roles (LUR) work (standard RADIUS), but Downloadable User Roles (DUR) do not — the HTTPS/TLS authentication for DUR fails because the required credentials were not configured correctly.

Why the Other Options Are Incorrect:

A. Add a new Enforcement Policy of type "WEBAUTH" on ClearPass:WebAuth enforcement policies are unrelated to DUR. Downloadable User Roles are delivered using an Aruba Downloadable Role enforcement profile, not WebAuth.

“Downloadable roles are defined and enforced through the Aruba Downloadable Role profile type. WebAuth policies are used for captive portal authentication only.”

C. Uncheck the "Dynamic Authorization" checkbox:Dynamic Authorization (RFC 3576 or CoA) allows session reauthentication or role changes. Disabling this feature would not fix DUR, as DUR relies on CPPM credentials for HTTPS authentication.

“Dynamic Authorization (CoA) enables session updates but does not control role download authentication.”

D. Modify the shared secret on the switch using the 'radius-server host' command:This option applies to switch RADIUS configuration, not Aruba Central APs or gateways. The DUR process uses HTTPS with ClearPass credentials, not the RADIUS shared secret.

“The RADIUS shared secret is used for authentication requests, not for downloadable role retrieval. Downloadable roles require valid CPPM credentials.”

References of HPE Aruba Networking Switching Documents or Study Guide:

Aruba Central Management and Configuration Guide — Downloadable Roles Section(Explains CPPM Username/Password requirement and DUR HTTPS authentication process.)

Aruba ClearPass Policy Manager Configuration Guide — Aruba Downloadable Role Enforcement Profiles(Details the role download process and ClearPass credential validation.)

ArubaOS-Switch and AOS-CX Security Configuration Guide — Role-Based Access Control and ClearPass Integration(Describes the mechanism for DUR retrieval and the use of HTTPS between the Aruba device and ClearPass.)

The command shown in the exhibit is:

Access-1# show ubt state

This command displays the User-Based Tunneling (UBT) status on an Aruba CX switch. UBT allows wired access devices (like CX 6300/6400) to extend tunneled connectivity to Aruba gateways, using GRE tunnels for user traffic.

The output contains the following sections:

1. Local Conductor Server (LCS) State

Primary : 172.16.200.252 ready_for_bootstrap operational_primary

Secondary : 172.16.200.253 ready_for_bootstrap operational_secondary

This confirms that two gateways (IP 172.16.200.252 and 172.16.200.253) form an LCS pair in an Aruba gateway cluster.

Exact extract:

“The Local Conductor Servers (LCS) represent the pair of Aruba Gateways that control and terminate UBT tunnels. One operates as the primary (active) and the other as the secondary (standby). These gateways must be configured as a cluster pair.”

2. Switch Anchor Controller (SAC) State

Active : 172.16.200.252 20:4c:03:81:e7:ca registered

Standby : 172.16.200.253 20:4c:03:b2:12:0a registered

Both gateways are registered as active and standby switch anchor controllers. This is a clear indication that the switch (Access-1) has successfully established tunnels to both gateways within the cluster.

Exact extract:

“The Switch Anchor Controller (SAC) section lists both cluster members to which the switch forms GRE tunnels. The switch maintains active and standby tunnels for redundancy.”

3. User Anchor Controller (UAC) State

Each connected user is mapped to a User Anchor Controller (UAC) — one of the two gateways — depending on cluster load balancing:

User Anchor Controller (UAC): 172.16.200.252

User Anchor Controller (UAC): 172.16.200.253

Each user session is anchored on a specific gateway within the cluster. The presence of two different UAC IPs confirms that users are being distributed across both gateways — a behavior that occurs only in a clustered gateway configuration.

Exact extract:

“In a clustered gateway deployment, each user session is dynamically anchored to one of the gateways. The UAC field shows which gateway currently handles each user session.”

Conclusion:

From the output:

Two gateways are shown as primary and secondary LCS.

Both are registered as SACs (tunnel endpoints).

Users are distributed across both gateways as UACs.

This confirms that Access-1 (the CX switch) has established GRE tunnels to a pair of gateways within a cluster.

Hence, the correct answer is A. A pair of gateways within a cluster.

Why the Other Options Are Incorrect:

B. A pair of switches running VXLAN:UBT tunnels are GRE-based and terminate on Aruba Gateways, not VXLAN-enabled switches.

“User-Based Tunneling uses GRE tunnels to Aruba Gateways; VXLAN is not used for UBT.”

C. A single gateway within a cluster:The output explicitly shows two controllers (active and standby) registered — not a single one.

D. A pair of standalone gateways:The LCS state shows primary/secondary operational roles, which exist only in a cluster, not standalone gateways.

References of HPE Aruba Networking Switching Documents or Study Guide:

ArubaOS-CX Access Security and UBT Configuration Guide – “Understanding User-Based Tunneling (UBT), LCS, SAC, and UAC roles.”

Aruba Gateway Clustering and Redundancy Guide – “Cluster operation and role distribution for UBT.”

Aruba Campus Wired and Wireless Integration Guide – “How CX switches form UBT tunnels to clustered Aruba gateways.”

Aruba Zero Trust Access Design Guide – “High availability with UBT across gateway clusters.”

Multi-Pre-Shared Key (MPSK) with ClearPass is the recommended solution for a scenario where the IT Helpdesk needs to configure IoT devices to connect to a single SSID using unique PSKs. MPSK allows for the use of different PSKs on the same SSID, and ClearPass enables the management of these unique keys efficiently.

Understanding the error:

The key line in the error message is:

fatal alert by server - unknown_ca

tls_process_client_certificate:certificate verify failed

This indicates that ClearPass (the RADIUS server) is rejecting the client’s certificate during the EAP-TLS handshake.

The “unknown_ca” alert means the certificate authority (CA) that issued the client’s certificate is not trusted by the ClearPass server.

Why Option D is correct:

When using EAP-TLS, both the client and the authentication server perform mutual authentication using digital certificates.

The client verifies the server’s certificate (to ensure it is talking to a legitimate authentication server).

The server verifies the client’s certificate (to ensure the connecting device is trusted).

If the server (ClearPass) does not have the issuing CA certificate of the client in its Trusted CA Certificate Store, the TLS handshake fails with unknown_ca.

Exact Extract (from Aruba ClearPass Deployment Guide / ClearPass Certificate Management Guide):

“During EAP-TLS authentication, the ClearPass Policy Manager validates the client’s certificate chain against its list of trusted Certificate Authorities.

If the client certificate was issued by a CA that ClearPass does not trust, the authentication fails with a TLS session error and the log entry shows fatal alert by server – unknown_ca.”

“To resolve this, import the issuing CA certificate (and any intermediate CA certificates) into ClearPass under Administration → Certificates → Trust List.”

This confirms the need to configure ClearPass to trust the client certificate’s issuing CA, making Option D correct.

Why the other options are incorrect:

A. Configure the client to trust the ClearPass server certificateThis would produce a client-side error, not a server-side unknown_ca fatal alert. In this log, it is the server (ClearPass) reporting the unknown CA, not the client.

Extract:

“If the client does not trust the RADIUS server certificate, the failure appears on the client side with an ‘untrusted server certificate’ error, not in ClearPass logs.”

B. Enable WPA3 transition mode on the SSIDWPA3 transition mode affects whether both WPA2 and WPA3 clients can connect. It does not affect EAP-TLS or certificate verification.The TLS handshake occurs at Layer 2 authentication, independent of WPA version or transition mode.

Extract:

“Transition mode is unrelated to 802.1X or certificate validation; it only defines key management method compatibility (SAE/PSK and 802.1X coexistence).”

C. Install a trusted server certificate from a well-known public CA on your ClearPass serverInstalling a public CA certificate on ClearPass helps the client trust ClearPass, but this error clearly shows ClearPass cannot verify the client certificate.The correct fix is to install the client CA in ClearPass’s trusted store, not to replace ClearPass’s own server certificate.

Extract:

“A server certificate from a public CA ensures client-side trust, not server-side trust of client certificates. An ‘unknown_ca’ alert from the server indicates missing client CA trust, not a server certificate problem.”

Final Summary:

Error Source

Meaning

Corrective Action

unknown_ca reported by server

Server (ClearPass) does not trust client’s CA

Import client’s CA certificate into ClearPass trusted store

unknown_ca reported by client

Client does not trust RADIUS server’s certificate

Install proper server certificate or CA chain on ClearPass

Answer: D — Configure ClearPass to trust the client certificate

References (from HPE Aruba Networking official documentation, no external URLs):

Aruba ClearPass Policy Manager 6.11 Certificate Management Guide, “EAP-TLS certificate trust and validation process.”

Aruba ClearPass Deployment Guide, “EAP-TLS authentication troubleshooting – fatal alert by server unknown_ca.”

ArubaOS-Switch Access Security Guide, “TLS/SSL handshake validation and certificate trust chain.”

Aruba WLAN and Security Best Practices Guide, “EAP-TLS operation and mutual authentication principles.”

The fallback role is used as a default role in the absence of a specified role or when an authentication server is not available. Given the scenario, where the test device with MAC address 81:cd:93:13:ab:31 needs to be assigned to "iot-prod" and other devices to "iot-default", and considering there is no external authentication server configured for the test, the appropriate action would be to set a global fallback role that applies to all devices connecting to the network. This ensures that any device that does not match the specific device profile will inherit the "iot-default" role. Since the configuration for a specific MAC address (81:cd:93:xx:xx:xx) to associate with the "iot-prod" role is already in place, setting the fallback role globally accommodates the requirement for other devices.