HPE6-A47 Exam Dumps - Designing Aruba Solutions

One Aruba best practice for this design is to ensure that optimization and suppression of unnecessary multicast is enabled on the MCs. This is because multicast traffic can consume a lot of bandwidth and degrade the wireless performance, especially in a large building with many devices. By enabling optimization and suppression of unnecessary multicast, the MCs can reduce the amount of multicast traffic that is sent to the APs and the wireless clients, and improve the network efficiency and user experience.

Option A is incorrect because extending VLAN 10 to the edge and deploying Aruba APs on it is not a best practice for this design. This is because it creates a large broadcast domain that can increase the network congestion and complexity. It also exposes the VLAN 10 to potential security risks from the edge devices. Option B is incorrect because ensuring that each user role on the MCs is associated with a different VLAN ID is not a best practice for this design. This is because it creates a large number of VLANs that can increase the network overhead and management difficulty. It also limits the flexibility and scalability of the network design. Option C is incorrect because ensuring that the RADIUS server assigns users to different VLANs dynamically is not a best practice for this design. This is because it adds an extra layer of complexity and dependency to the network design. It also requires the RADIUS server to be configured and synchronized with the MCs and the VLANs, which can introduce potential errors and delays. References: Aruba Validated Design: Campus Wireless LAN), ArubaOS 8.7 User Guide)

The customer wants to use certificates to authenticate user devices, which means that they need a strong and secure method of verifying the identity of the devices that connect to the employee WLAN. The best option for this is to use EAP-TLS instead of PEAP-MSCHAPv2. EAP-TLS stands for Extensible Authentication Protocol-Transport Layer Security, and it is a protocol that uses certificates on both the client and the server side to establish a mutual authentication and a secure channel for data exchange. EAP-TLS is considered the most secure EAP method, as it prevents common attacks such as dictionary attacks, man-in-the-middle attacks, and replay attacks.

The other options are not suitable for the customer requirements:

• Option B is incorrect because TKIP encryption is weaker than AES encryption. TKIP stands for Temporal Key Integrity Protocol, and it is an older encryption method that was designed to replace WEP, which had serious security flaws. However, TKIP also has some vulnerabilities, and it is not recommended for modern WLANs. AES stands for Advanced Encryption Standard, and it is a newer and stronger encryption method that provides better security and performance for WLANs.
• Option C is incorrect because WPA2-PSK is less secure than WPA2-Enterprise. WPA2-PSK stands for Wi-Fi Protected Access 2-Pre-Shared Key, and it is a security mode that uses a common passphrase or key to authenticate all devices that connect to the WLAN. However, this passphrase or key can be easily compromised or shared, and it does not provide individual authentication or encryption for each device. WPA2-Enterprise stands for Wi-Fi Protected Access 2-Enterprise, and it is a security mode that uses a RADIUS server to authenticate each device individually and dynamically generate encryption keys for each session. WPA2-Enterprise provides better security and scalability for WLANs.
• Option D is incorrect because TTLS does not use certificates to authenticate user devices. TTLS stands for Tunneled Transport Layer Security, and it is a protocol that uses certificates only on the server side to establish a secure tunnel for data exchange. The client side can use different methods to authenticate, such as passwords, tokens, or certificates. However, TTLS does not require certificates on the client side, and it is less secure than EAP-TLS.

References:

• ArubaOS 8.5 User Guide)
• ArubaOS 8.5 Security Guide)
• Aruba Certified Design Professional Official Certification Study Guide (HPE6-A47))

 References:https://www.arubanetworks.com/assets/ds/DS_7200Series.pdf

• Aruba Mobility Controller Data Sheet (Aruba Networks)
• Designing Aruba Solutions Study Guide (HPE Press)

ClearPass Access licenses are required for each unique endpoint that authenticates to ClearPass using any supported protocol, such as 802.1X, MAC authentication, web authentication, or VPN authentication1. ClearPass Onboard licenses are required for each unique endpoint that is provisioned with a certificate using the ClearPass Onboard service2. In this scenario, the customer has 900 employees and up to 30 guests a day, which means there are at most 930 users who need to authenticate to the network. Assuming each user has about two or three devices, the maximum number of devices that need Access licenses is 930 x 3 = 2790, which can be rounded up to 3000. The customer also wants to use certificates to authenticate user devices, which means they need Onboard licenses as well. However, the customer only issues laptops to the employees, which means only 900 devices need Onboard licenses. Therefore, the architect should include 3000 Access licenses and 1000 Onboard licenses in the proposal. References:

• 1: ClearPass Licensing Guide - Aruba
• 2: ClearPass Onboard Data Sheet - Aruba

This is the general recommendation from the AirWave Server Sizing Guide1, which provides guidelines for selecting and configuring hardware based on the number of devices, clients, and features. The guide also lists the conditions that impact hardware sizing, such as polling frequency, RAPIDS, VisualRF, and Clarity.

References: 1: AirWave 8.2.14.0 Server Sizing Guide - Aruba, page 5.

Deployed as a purpose-built hardware or virtual machine image, each AirWave server supports up to 4,000 network devices (access points, switches, and controllers).https://www.arubanetworks.com/assets/ds/DS_AW.pdf

The customer needs a solution that can terminate VPN tunnels for Aruba RAPs, which are remote access points that connect to the corporate network over the Internet. The customer has only one public IP address, which means that they need to use NAT to forward the IPsec traffic to the device that will terminate the VPN tunnel. The customer also wants N+1 redundancy, which means that they need at least two devices that can act as backup for each other in case of failure.

The solution that meets the customer requirements is to use two Aruba MCs on the same subnet that use VRRP without clustering. VRRP stands for Virtual Router Redundancy Protocol, and it is a protocol that allows multiple devices to share a virtual IP address and act as a single gateway for the network. This way, the customer can use the virtual IP address as the public IP address for the NAT, and the IPsec traffic will be forwarded to the device that is the VRRP master. If the master device fails, the backup device will take over the role of the master and continue to terminate the VPN tunnels. This provides N+1 redundancy for the customer.

The other options are not suitable for the customer requirements:

• Option B is not suitable because a Layer 3 cluster requires two public IP addresses, one for each MC. The customer only has one public IP address, so they cannot use this option.
• Option C is not suitable because VRRP does not work across different subnets. The customer needs to have the MCs on the same subnet to use VRRP.
• Option D is not suitable because a Layer 2 cluster does not support NAT. The customer needs to use NAT to forward the IPsec traffic to the MCs.

References:

• Aruba Remote Access Point (RAP) Networks Validated Reference Design)
• Aruba Mobility Controller Virtual IP Configuration Guide)
• ArubaOS 8.5 User Guide)

To route at the core and extend some of the same VLANs in different buildings, the architect should recommend creating a backplane stack at the aggregation layer and a VSF fabric at the core. A backplane stack is a logical switch that combines multiple physical switches into a single unit, using dedicated stacking cables or ports. A VSF fabric is a virtual switch that combines multiple physical switches into a single unit, using standard Ethernet links. Both technologies provide high availability, scalability, and simplified management for the network12.

By creating a backplane stack at the aggregation layer, the architect can reduce the number of routing interfaces and routing protocols needed at the core layer, as well as simplify the configuration and maintenance of the aggregation switches. By creating a VSF fabric at the core layer, the architect can enable Layer 2 connectivity across different buildings, as well as provide redundancy and load balancing for the core switches. The VSF fabric can use Multi-Chassis Link Aggregation (MC-LAG) to extend the same VLANs to different aggregation stacks, without creating loops or blocking ports3.

The other options are not suitable for the customer’s requirements. Implementing broadcast filtering on switch-to-switch links across all of the buildings would not enable Layer 2 connectivity across different buildings, as it would prevent the propagation of Layer 2 control traffic, such as Spanning Tree Protocol (STP) and VLAN Trunking Protocol (VTP). Combining all switches in the aggregation layer and core into a single backplane stack would not be feasible, as it would require compatible switches and sufficient stacking ports or cables, as well as create a single point of failure for the entire network. Using VRRP on the core and aggregation switches, with the aggregation switches acting as standby, would not eliminate the routing at the aggregation layer, as it would still require the aggregation switches to participate in the routing process and maintain routing tables.

References:

• ArubaOS-Switch Stacking Guide
• ArubaOS-Switch Virtual Switching Framework Configuration Guide
• Aruba Validated Reference Design: Campus Wired LAN

The specifications for the AP models are in the format of Tx:Rx:SU-MIMO:MU-MIMO:MU-MIMO clients, where Tx is the number of transmit antennas, Rx is the number of receive antennas, SU-MIMO is the number of spatial streams supported in single-user MIMO mode, MU-MIMO is the number of spatial streams supported in multi-user MIMO mode, and MU-MIMO clients is the number of MU-MIMO clients that can be served simultaneously.

The customer requirements are:

• Support for MU-MIMO: This means the AP must have a MU-MIMO value greater than 1, as MU-MIMO is a technique that allows multiple spatial streams to be transmitted to different clients at the same time.
• Support for up to four spatial streams, both when MU-MIMO is used and when it is not used: This means the AP must have a SU-MIMO value and a MU-MIMO value of 4, as spatial streams are independent data streams that can be transmitted or received by an antenna.
• Support for transmissions to up to three MU-MIMO clients at the same time: This means the AP must have a MU-MIMO clients value of 3, as this indicates the maximum number of clients that can receive MU-MIMO transmissions from the AP at the same time.

Based on these criteria, only the AP 335 meets the customer requirements, as it has a specification of 4x4:4:4:4:3, which means it has 4 transmit and receive antennas, 4 spatial streams in both SU-MIMO and MU-MIMO modes, and can serve 3 MU-MIMO clients simultaneously. The AP 325 does not meet the customer requirements, as it has a specification of 4x4:4:4:3:3, which means it has only 3 spatial streams in MU-MIMO mode, and can only serve 2 MU-MIMO clients simultaneously.

References:

• Aruba AP-335 Wireless Access Point | Aruba
• Aruba AP-325 Wireless Access Point | Aruba
• Multi-User MIMO in WiFi 6 - Arista Networks