Pass the HP Aruba Certified Professional - Campus Access HPE7-A07 Questions and answers with Dumpstech

The CLI output provided shows routing information from a CX 6300 switch. The output under "VRF: default" shows various IP routes, including a route for 10.203.1.100/32 with a next hop of 172.21.11.2. This indicates that the route to the client with IP address 10.203.1.100 is known in the network and is reachable via another device in the fabric, which has the loopback IP address 172.21.11.2. Since the route is present in the routing table, it means that the client is known and active within the fabric network.

In HPE Aruba Networking (AOS-CX and AOS-Switch) OSPF implementation, the routing behavior for external routes (Type 5 LSAs) distinguishes between two types of external advertisements:

E1 (Type-1 external) — The total path cost is calculated as the sum of the internal cost to reach the ASBR (Autonomous System Boundary Router) plus the external cost as advertised in the LSA.

E2 (Type-2 external) — The external cost is considered independent of the internal OSPF path cost to reach the ASBR. Thus, the metric used is only the external cost from the LSA.

When both an E1 and an E2 route exist to the same external destination, OSPF gives preference to the E1 route, regardless of metric values, because the E1 route represents a more accurate total cost to the destination (including internal OSPF cost).

Extract (as per HPE Aruba OSPF Technical Overview and AOS-CX Routing Guide):

“When both Type-1 (E1) and Type-2 (E2) external LSAs for the same destination are present, the router always prefers the Type-1 route. Type-1 routes include both internal and external costs in the total metric, while Type-2 routes use only the external cost. The E1 path is therefore considered more precise and is selected as the preferred route.”

This is consistent across Aruba’s OSPF implementation and follows standard OSPF behavior as defined by the protocol (RFC 2328).

Therefore, when both E1 and E2 routes are available and have the same overall cost, the router will always prefer the E1 path.

The CLI output displays EVPN routes and their corresponding next hops. The "Route Distinguisher" entries followed by IP addresses in the 172.21.11.x range indicate these are loopback addresses used by the underlay network. The underlay network provides the basic routing and forwarding plane for the overlay network that EVPN is part of. These loopback addresses are crucial for the proper functioning of the EVPN control plane.

The issue indicated by the output is an invalid pre-shared key (PSK). The logs show multiple failures during the WPA2 key exchange process, which points to a mismatch between the PSK configured on the client device and the PSK expected by the AOS 10 mobility gateway.

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.).

Applying the 'acmethreshold' profile as shown in the exhibit would set a minimum and maximum threshold for queue 0, which affects the drop probability for traffic that exceeds these thresholds. The yellow marking indicates a medium drop precedence, so yellow-flagged traffic would be more likely to be dropped when congestion occurs, and the uplink is over-utilized. This action is intended to protect higher-priority traffic, such as VoIP, by giving it a lower probability of being dropped.

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

VOQ (Virtual Output Queuing) is a hardware-based queuing mechanism used in the ArubaOS-CX architecture to prevent head-of-line blocking and minimize packet drops in high-throughput environments.

How VOQ Works:

Each ingress port maintains a separate queue for every egress port in the system.

When a packet arrives, it is placed in the ingress buffer corresponding to its destination egress port.

This structure ensures that traffic destined for one congested egress port does not block packets heading to other ports.

This architecture is critical in high-speed modular switches and aggregation cores (such as the Aruba 8400 and 10000 Series), allowing the fabric interconnect to forward traffic efficiently without dropping packets due to port congestion.

ArubaOS-CX Technical Extract:

“Virtual Output Queuing (VOQ) provides per-egress-port queuing at ingress buffers, preventing head-of-line blocking and ensuring high throughput across the switch fabric. Each ingress queue corresponds to a specific egress port, allowing packets to be transmitted as soon as the egress port becomes available.”

Option Analysis:

A. Incorrect – Refers to priority marking (QoS), not VOQ operation.

B. Correct – VOQ provides ingress buffers with queues for each egress port, reducing dropped packets and head-of-line blocking.

C. Incorrect – VOQ is not related to LACP or VSX link aggregation.

D. Incorrect – VOQ does not dynamically allocate egress buffer space; it segregates ingress queues per egress destination.

Final Verified Answer: B

Reference Sources (HPE Aruba Official Materials):

Aruba AOS-CX Technical Architecture Overview – Virtual Output Queuing (VOQ)

Aruba 8400/10000 Series Switches Hardware and Performance Guide

Aruba Certified Switching Expert (ACSE) Study Guide – Switch Fabric and Queuing Mechanisms

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.

In a packet capture from an upstream switch port mirror, you would see the VLAN assignment. The port mirror captures the traffic as it is on the network, including any VLAN tags. GRE or IPsec tunnels encapsulate the original packet, including VLAN tags, but the VLAN information is not visible within the encapsulation headers.

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.