HPE7-A07 Exam Dumps - Aruba Certified Campus Access Mobility Expert Written Exam

In an Aruba network, if an SSID is configured for a primary and secondary gateway cluster with cluster preemption enabled, each AP individually will decide to move to the secondary gateway cluster if all of the nodes in the primary gateway cluster are down. This decentralized decision-making process enhances network resilience and ensures uninterrupted service for clients connected to the APs.

In the provided frame capture, we can clearly observe the following sequence of events:

802.11 Association and 4-Way Handshake:

The client (MAC 20:0d:b0:41:5d:b6) associates with the AP (b8:3a:5a:84:24:30).

The EAPOL 4-way handshake successfully completes (Key Messages 1–4), indicating that the client has successfully joined the secured SSID.

This rules out authentication issues or WPA3 key management errors.

DHCP Exchange:

The client sends a DHCP Request, and the server responds with a DHCP ACK, confirming that the client has successfully obtained an IP address.

Example in the capture:

DHCP Request – Transaction ID 0xd3da62ef

DHCP ACK – Transaction ID 0xd3da62ef

This confirms that DHCP negotiation completed successfully.

ARP Requests and Replies:

After DHCP completion, an ARP broadcast is seen:

Who has 192.168.10.17? Tell 192.168.10.158

This is a normal ARP request from another device trying to reach 192.168.10.17.

However, we also see ARP replies for:

192.168.10.1 is at 00:1c:7f:7b:d2:4d

This indicates the default gateway responding with its MAC address.

Analysis of the Connectivity Issue:Even though the gateway is sending ARP replies, the repeated ARP responses for 192.168.10.1 in the capture suggest that the client is not caching or acknowledging the ARP entry for the default gateway. This behavior is consistent with a client that does not have a valid or populated ARP entry for its default gateway, leading to traffic failures beyond the local subnet.

This could be due to:

Incorrect ARP response handling on the client.

Firewall or driver issues preventing the ARP reply from being processed.

Power-save or roaming conditions where the ARP table did not update properly.

Exact Extract from HPE Aruba Networking Switching and WLAN Troubleshooting Documentation:

“If a client successfully completes the 4-way handshake and DHCP exchange but fails to pass traffic beyond the local subnet, check for ARP resolution issues.

Missing or invalid ARP entries for the default gateway can prevent Layer 3 connectivity even though the wireless association is successful.”

“Wireshark traces showing repeated ARP replies from the gateway indicate that the gateway is responding, but the client may not be updating its ARP cache, leading to connectivity failures.”

Hence, the conclusion is that the client’s ARP entry for the default gateway is missing or invalid, explaining why connectivity fails despite successful association and DHCP negotiation.

Why the Other Options Are Incorrect:

B. The SSID is using WPA3-Enterprise key management:The handshake shown (EAPOL 4 messages) uses the standard WPA2/AES (EAPOL-Key) exchange. There are no SAE or WPA3 transition frames present.

“WPA3 uses SAE or 802.1X with PMF indicators; the frame capture shows standard WPA2 key exchange.”

C. The client has not obtained an IP address on this network previously:The DHCP Request and ACK exchange confirm that the client has obtained an IP address (192.168.10.158). This option is invalid.

“A completed DHCP ACK indicates the client successfully received an IP address.”

D. The AP is using 20MHz wide 5GHz channels:The frame capture shows VHT/HE announcements, which indicate High Efficiency (HE) capabilities and channel sounding, not 20MHz restrictions. Channel width has no relation to the connectivity failure described.

“VHT/HE frames are part of 802.11ac/ax operation and do not indicate channel width problems.”

References of HPE Aruba Networking Switching Documents or Study Guide:

Aruba WLAN Troubleshooting and Analysis Guide – “ARP, DHCP, and Gateway Reachability Troubleshooting.”

ArubaOS 10 Wireless Fundamentals and Diagnostics Guide – “802.11 Association, 4-Way Handshake, and ARP Behavior.”

Aruba Client Connectivity Troubleshooting Guide (AOS-10 and AOS-8) – “Identifying ARP Cache Issues Post-DHCP Assignment.”

Aruba Network Access and Layer 2 Troubleshooting Guide – “Role of ARP in Wireless Client Connectivity.”

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

RAPIDS (Rogue AP Detection System) in Aruba Central or AirWave works by correlating information between wireless and wired infrastructure to detect rogue devices and identify their wired connectivity location.

When Aruba Central detects a rogue AP or interfering device, it uses wired-side discovery mechanisms such as LLDP (Link Layer Discovery Protocol) to trace the device’s physical connection.

If the managed switch supports LLDP, it advertises and records neighbor information, including device type, MAC address, and connected port. Aruba Central queries this LLDP neighbor table from managed switches to determine the exact switch port where the rogue AP is physically connected.

Aruba Central and RAPIDS Documentation Extract:

“Aruba Central correlates rogue or interfering AP MAC addresses with wired-side discovery data. Using LLDP neighbor table information from managed switches, Central identifies the physical switch port where the rogue device is connected.”

Other options such as the MAC address table can show where a MAC is learned, but LLDP provides the direct, authenticated neighbor relationship that allows Aruba Central to accurately identify the rogue AP connection point and display it in the dashboard.

Option Analysis:

A. Incorrect – Device profiling identifies endpoint types, not wired connection ports for rogue AP detection.

B. Incorrect – MAC tables alone don’t provide direct port-device mapping context for rogue detection in Central.

C. ✅ Correct – Aruba Central uses LLDP neighbor data from managed switches to map rogue or interfering APs to specific switch ports.

D. Incorrect – AP MAC address tables exist in controllers or APs, not in Central’s rogue-tracking mechanism.

✅ Final Verified Answer: C

📘 Reference Sources (HPE Aruba Official Materials):

Aruba Central Administration and RAPIDS Configuration Guide

ArubaOS-Switch and CX Network Management Fundamentals – LLDP Discovery Integration

Aruba Certified Network Security Professional (ACNSP) Study Guide – Rogue AP Detection and Wired Correlation

In Aruba gateways/switches, LLDP decodes and displays standard LLDP TLVs by default. LLDP-MED inventory TLVs (including Asset ID) are shown only when LLDP-MED is enabled.

When LLDP-MED is not enabled, received MED TLVs are counted as Unknown TLVs and are not decoded in the neighbor detail output.

In the exhibit, show lldp statistics shows “Unknown TLVs: 2” and show lldp neighbor ... detail displays only basic LLDP fields (Chassis ID, Mgmt Address, Port Description, MTU), with no MED inventory fields such as Asset ID. This is the expected symptom of LLDP-MED being disabled.

LLDP TX is not required to receive and display neighbor TLVs; the missing Asset ID is unrelated to transmit state. MTU is also not relevant to TLV decoding.

References (HPE Aruba official materials): Aruba AOS-CX LLDP/LLDP-MED configuration—MED must be enabled to advertise/parse MED inventory TLVs (Asset ID, Serial, HW/FW/SW, etc.).

The existing configuration for the WLAN ssid-profile has enabled MAC authentication which, while suitable for IoT devices that may not support 802.1X, can interfere with the normal 802.1X authentication process for other devices. By removing the mac-authentication directive from the WLAN configuration, the non-IoT 802.1X devices should be able to connect without issues as the authentication process will not be disrupted by MAC authentication checks. This adjustment ensures that the WLAN ssid-profile is correctly aligned with the authentication requirements for both IoT and non-IoT devices within the network environment, conforming to the best practices for mixed-device WLAN configurations.

The Aruba AOS-CX BGP Best Path Selection Process determines which route becomes the active (>) route in the BGP routing table.

This process is consistent with RFC 4271 but detailed in HPE’s Aruba AOS-CX Routing Guide and ACSP Study Guide – BGP and Dynamic Routing.

Extract 1 — BGP Path Selection Hierarchy (Aruba AOS-CX Routing Guide)

“When multiple BGP routes exist to the same destination, the router uses the following decision sequence to select the best path:

Highest LOCAL_PREFERENCE

Lowest AS_PATH length

Lowest ORIGIN type (IGP ‘i’ preferred over EGP ‘e’, preferred over Incomplete ‘?’)

Lowest MULTI_EXIT_DISC (MED) if received from the same AS

Lowest IGP cost to the next hop (closest exit)

Lowest BGP router ID as tie-breaker.”

Extract 2 — Aruba Certified Switching Professional (ACSP) Study Guide – BGP Path Decision

“Local Preference is the first and most significant criterion within a single AS.

A higher Local Preference value indicates a preferred exit.

If multiple routes have equal Local Preference, the router compares their Origin Codes.

An Origin Code of ‘i’ (IGP) is preferred over ‘?’ (Incomplete).

If still tied, the route with the lowest IGP cost to the next-hop is chosen as best.”

Step-by-Step Application to the Table

Step 1 – Local Preference

Routes B, D, and E have Local Preference = 100

Routes A and C have Local Preference = 0

✅ Routes A and C are eliminated.

Remaining candidates: B, D, E

Step 2 – Origin Code

D and E: Origin Code = i (IGP) → Preferred

B: Origin Code = ? (Incomplete) → Less preferred

✅ Eliminate B

Remaining candidates: D, E

Step 3 – MED / Metric

Both D and E have Metric = 0 → Still tied

Step 4 – IGP Cost / Administrative Distance

D: Distance = 200

E: Distance = 20

According to ArubaOS-CX:

“When all BGP attributes are equal, the route with the lowest internal cost (shortest IGP distance) to the next-hop is selected.”

✅ E wins because it has a lower distance (20 < 200)

Extract 3 — ArubaOS-CX Routing Reference

“The route that wins the selection process is marked with a ‘>’ symbol in the routing table.

This route is installed in the forwarding table and used for traffic forwarding.”

Final Explanation

Route E has:

Highest Local Preference (100)

Best Origin (IGP ‘i’)

Lowest IGP distance (20)

Hence, Route E is selected as the best path, and the “>” symbol is placed beside it in the BGP routing table.

✅ Final Verified Answer: E

📘 Official Aruba Documentation References:

Aruba AOS-CX Routing Guide – Section: BGP Best Path Selection Criteria

Aruba Certified Switching Professional (ACSP) Study Guide – Module: BGP and Path Selection Logic

Aruba AOS-CX Configuration and Management Guide – Command: show ip bgp summary / route selection

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.

When configuring Virtual Switching Extension (VSX) in a campus topology for link aggregation across two aggregation switches, it is important to synchronize Multi-Chassis Link Aggregation Group (MC-LAG) interfaces. The command "vsx-sync mclag-interfaces" ensures that the state and configuration of MC-LAG interfaces are synchronized between the two VSX-linked switches, providing consistent link aggregation and preventing any loops or mismatched configurations that might occur if the interfaces were not in sync.