HPE6-A47 Designing Aruba Solutions Questions and Answers

The correct answer is option C, 20-25. This is because a general rule of thumb for 802.11ac wireless deployment is to have one AP for every 200 square meters (approximately 2,000 square feet) of coverage area. This assumes a moderate user density and application demand. Therefore, for a coverage area of 4,645 square meters (approximately 50,000 square feet), the architect should have in mind about 23 APs (4,645 / 200 = 23.225). This number can be adjusted based on the actual site survey and VisualRF plan, but it serves as a good starting point. References: The information can be referenced from the official HPE documents and learning materials available on HPE Press and Aruba Networks. Specifically, it aligns with the objectives outlined in Chapter 4: Wireless LAN Design, where the AP count estimation and site survey methods are discussed. Designing Aruba Solutions Official Certification Study Guide Aruba Mobility Fundamentals Guide

To plan a wireless solution upgrade for printers, the architect needs to know whether the printers support 802.1X and the 802.11 standards supported by the printer. These two factors are important for ensuring the compatibility, security, and performance of the wireless network.

• 802.1X is a standard for network access control that provides authentication, authorization, and encryption for devices that connect to a wireless network1. It prevents unauthorized devices from accessing the network resources and protects the data transmission from eavesdropping or tampering. If the printers support 802.1X, the architect can design a wireless solution that leverages this feature to enhance the security and compliance of the network. If the printers do not support 802.1X, the architect may need to consider alternative methods of securing the wireless access, such as MAC address filtering, VPN, or WPA2-PSK2.
• 802.11 is a set of standards that define the specifications and protocols for wireless communication3. Different 802.11 standards have different characteristics, such as frequency, bandwidth, data rate, range, and compatibility. For example, 802.11a operates at 5 GHz and offers up to 54 Mbps, while 802.11b operates at 2.4 GHz and offers up to 11 Mbps3. If the printers support the same or higher 802.11 standards as the wireless network, the architect can design a wireless solution that ensures the optimal performance and reliability of the wireless communication. If the printers support lower or different 802.11 standards than the wireless network, the architect may need to consider the impact of the compatibility issues, such as interference, congestion, or degradation4.

The other options are not as relevant for planning a wireless solution upgrade for printers. Whether the printers are physically locked down or not does not affect the wireless connectivity, unless the lock interferes with the antenna or signal reception. The identity of users who need to access printers is more related to the access control and user management policies, rather than the wireless solution design. Whether the printers support PoE or not does not affect the wireless connectivity, unless the power source is unreliable or insufficient.

References:

• 1: https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/1-overview/802.1x.htm
• 2: https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/1-overview/securing-wireless-access.htm
• 3: https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/1-overview/802.11-standards.htm
• 4: https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/1-overview/compatibility-issues.htm

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)

For a VHD wireless network at a large events venue, the architect should ensure that the DHCP and DNS servers are carrier-grade and support a low transaction time. This is because the DHCP and DNS servers are responsible for providing IP addresses and name resolution for the wireless devices, and they need to handle a high volume of requests and responses in a short time. A low transaction time reduces the latency and improves the user experience. A carrier-grade server is a server that meets the high standards of reliability, availability, and scalability required by telecom operators and service providers. A carrier-grade server can handle a large number of concurrent connections, provide redundancy and fault tolerance, and offer high performance and security.

Option A is incorrect because the DHCP server can support a high number of scopes with a /24 size, but this does not guarantee a low transaction time or a carrier-grade service. A scope is a range of IP addresses that the DHCP server can assign to the clients. A /24 size means that each scope can have up to 254 hosts. However, the number of scopes does not affect the speed or quality of the DHCP service. Option B is incorrect because a third-party firewall integrates with ClearPass to filter the guest user traffic, but this does not affect the DHCP and DNS services. A firewall is a device that monitors and controls the network traffic based on predefined rules. ClearPass is a network access control solution that provides secure authentication and policy enforcement. A firewall integration with ClearPass can enhance the security and visibility of the guest user traffic, but it does not improve the performance or reliability of the DHCP and DNS servers. Option C is incorrect because a domain CA is set up to deploy certificates to a high volume of guest devices, but this does not affect the DHCP and DNS services. A certificate authority (CA) is an entity that issues digital certificates that verify the identity and authenticity of the devices. A domain CA is a CA that is part of a domain and can issue certificates to the domain members. A certificate deployment is a process of distributing and installing the certificates to the devices. A certificate deployment can improve the security and trust of the wireless network, but it does not improve the speed or quality of the DHCP and DNS servers. References: Aruba Validated Design: Very High Density 802.11ac Networks), Aruba Validated Design: Campus Wired LAN), Aruba Validated Design: Guest Access)

The transceivers that the architect should recommend for each pair of switches are two QSPF+ MPO. This option would provide 40 Gbps bandwidth per link, which is enough to meet the customer requirement of 80 Gbps for the link aggregation. The QSPF+ MPO transceivers use a single multi-fiber connector that can support up to 12 fibers, which is compatible with the customer’s existing OM4 multi-mode fiber infrastructure. The QSPF+ MPO transceivers also support distances up to 100 meters, which is sufficient for the customer’s inter-building connections.

The other options are not optimal for the customer requirement because they either provide insufficient bandwidth or require additional fiber strands. Two QSPF+ BiDi transceivers would provide only 20 Gbps bandwidth per link, which is half of the customer requirement. Eight SFP+ LR or SR transceivers would provide 80 Gbps bandwidth per link, which is more than the customer requirement, but they would also require eight fiber strands per link, which is more than the customer’s available fiber infrastructure. References:

• Aruba Transceiver and Cable Data Sheet (Aruba Networks)
• Designing Aruba Solutions Study Guide (HPE Press)

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)

The minimum acceptable signal for an active site survey depends on the type of applications and the data rates that the users require. For 802.11ac, which operates in the 5 GHz band, Aruba recommends a signal of -65 dBm or better for high-performance applications such as voice and video, and a signal of -72 dBm or better for basic applications such as Web and email1. These values are based on the receiver sensitivity of typical 802.11ac clients and the expected signal-to-noise ratio (SNR) for different modulation and coding schemes (MCS). A higher SNR means a higher data rate and a better user experience.

Therefore, the architect should look for a signal of -65 dBm in the 5 GHz band to determine the test AP range for 802.11ac, assuming that the users run high-performance applications. A signal of -75 dBm in the 5 GHz band might be too weak to support the desired data rates and quality of service. A signal of -65 dBm or -75 dBm in the 2.4 GHz band is irrelevant for 802.11ac, as it does not operate in that band.

References:

• Aruba Validated Reference Design: 802.11ac Networks
• Best Practices for Monitoring and Troubleshooting 802.11ac Networks

The Aruba Mobility Master (MM) hardware appliances are designed to manage large-scale networks. The MM-HW-10K model is capable of managing up to 10,000 devices, which would be sufficient for the customer’s requirement of supporting about 1,500 client APs and a maximum of about 20,000 wireless clients1. Two MM-HW-10K appliances would allow for an active and standby deployment, providing redundancy and ensuring network reliability2.

References:

• System Requirements - Aruba
• Mobility Master Hardware Appliance - Aruba

A wide sector directional antenna is a type of antenna that radiates or receives radio waves in a sector-shaped pattern, covering a wide angle of a circle. The width of the sector is determined by the horizontal beamwidth (H-plane) of the antenna, while the height of the sector is determined by the vertical beamwidth (E-plane) of the antenna12. A wide sector directional antenna is usually used to provide regional coverage for wireless networks, such as Wireless Internet Service Providers (WISP) or similar applications2.

According to the antenna specifications given, Antenna 3 has the widest horizontal beamwidth of 100 degrees, which means it can cover a large sector of a circle. Antenna 4 has a narrower horizontal beamwidth of 60 degrees, which means it can cover a smaller sector of a circle. Antenna 1 and Antenna 2 have a horizontal beamwidth of 360 degrees, which means they are omnidirectional antennas, not directional antennas. Therefore, Antenna 3 is the best choice for the plan that specifies wide sector directional antennas.

References:

• 1: https://en.wikipedia.org/wiki/Sector_antenna
• 2: https://lcantennas.com/directional-antennas/

An active site survey is a method of measuring and validating the wireless coverage, capacity, and performance of a network in a specific environment. It involves deploying temporary APs in the proposed locations, collecting data using a survey tool, and analyzing the results to optimize the network design. A heat map is a graphical representation of the wireless signal strength, interference, noise, or other metrics in different areas of the site. A heat map with proposed AP locations and actual tested coverage is a deliverable that shows the customer the expected performance of the new 802.11ac-based solution, and allows the architect to fine-tune the AP placement, channel selection, transmit power, and antenna orientation. This deliverable also helps the customer to verify that the network meets their requirements for coverage, capacity, and quality of service. References:

• Aruba Certified Design Professional Official Certification Study Guide (HPE6-A47) - Chapter 5)
• Aruba Validated Reference Design: Wireless LAN Site Surveys - Chapter 3)
• Aruba Validated Reference Design: 802.11ac Networks - Chapter 4)

The Aruba 7210 Mobility Controller is designed to support up to 512 APs and 16,384 simultaneous users. In contrast, the 7205 Mobility Controller supports up to 256 APs and 8,192 simultaneous users. Therefore, for a very high density (VHD) design with 128 APs supporting 12,800 devices, the 7210 controllers would be a better fit due to their higher capacity for APs and simultaneous users.

References:

• Designing Aruba Solutions, Rev. 20.11, Module 4: Aruba Mobility Controller Design, page 4-16
• 7200 Series Controller Data Sheet, page 1

According to the Designing Aruba Solutions course, dedicated Air Monitors (AMs) are APs that are configured to scan all channels for wireless threats and perform wireless intrusion prevention system (WIPS) functions. One of the advantages of using dedicated AMs over APs that are doing WIPS in AP mode (hybrid) is that AMs can implement wireless containment on any channel on which they detect a threat without affecting the service of legitimate clients. Wireless containment is a technique that prevents rogue APs or clients from communicating with the network by sending deauthentication or disassociation frames to them. However, if an AP that is serving clients performs wireless containment on a different channel, it will have to switch channels frequently, which will degrade the performance and user experience of the clients. Therefore, dedicated AMs are recommended for customers who need effective and efficient wireless containment without compromising client service.

References:

• Designing Aruba Solutions, Rev. 20.11, Module 5: Aruba Security Design, page 5-13
• Aruba Validated Reference Design: Wireless Intrusion Prevention System, page 10

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

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

The architect should propose one LIC-MM-VA-500 license package for the customer. This license package allows the customer to deploy up to two VMMs and manage up to 500 MCs and 10,000 APs. The customer does not need any additional licenses for the MCs or the APs, as they are included in the LIC-MM-VA-500 package. The other options are either insufficient or excessive for the customer’s needs.

• Option A is insufficient because six LIC-MM-VA-50 licenses only allow the customer to manage up to 300 MCs and 6,000 APs. The customer needs to manage 300 APs and six MCs, so this option does not meet the requirement.
• Option B is excessive because one LIC-MC-VA-250 and one LIC-MC-VA-50 licenses allow the customer to deploy up to 300 MCs and 6,000 APs, which is more than what the customer needs. Moreover, one LIC-MM-VA-500 license allows the customer to deploy up to two VMMs and manage up to 500 MCs and 10,000 APs, which is also more than what the customer needs. Therefore, this option is wasteful and unnecessary.
• Option D is also excessive because one LIC-MC-VA-250 and one LIC-MC-VA-50 licenses allow the customer to deploy up to 300 MCs and 6,000 APs, which is more than whatthe customer needs. Additionally, six LIC-MM-VA-500 licenses allow the customer to deploy up to 12 VMMs and manage up to 3,000 MCs and 60,000 APs, which is way more than what the customer needs. Therefore, this option is also wasteful and unnecessary.

References:

• ArubaOS 8.5 Licensing Guide)
• Aruba Mobility Master Data Sheet)
• Aruba 7000 Series Mobility Controllers Data Sheet)

SmartLink is a technology that provides fast failover for access switches connected to the core VSF fabric. It detects link failures on the uplink ports and switches to the backup link within 50 ms. It also shuts down the primary link to prevent loops. SmartLink works with any routing protocol and does not require any additional configuration on the core switches. OSPF graceful restart is a feature that allows OSPF to continue forwarding traffic during a planned or unplanned restart of the routing process. However, it does not provide fast failover for link or device failures. BGP is a routing protocol that is mainly used for inter-domain routing and does not provide fast failover for link or device failures. VRRP is a protocol that provides redundancy for routers by creating a virtual router with a shared IP address. However, it does not provide fast failover for link or device failures. References: ArubaOS-Switch Management and Configuration Guide for WC.16.10), Aruba Validated Design: Campus Wired LAN)

the new 802.11ac deployment should have a capacity-based design for the best performance, but the existing deployment sounds like a coverage-based design. This is because a capacity-based design takes into account the number and type of clients, the applications they use, and the bandwidth they require. A coverage-based design only considers the signal strength and the absence of coverage holes. A site survey is desirable to determine the optimal locations for the new APs because it can help the architect to assess the current and future capacity needs, identify the sources of interference and noise, and optimize the channel and power settings for the new APs.

Option A is incorrect because an 802.11ac deployment does not necessarily work better with side-mounted APs. The mounting location of the APs depends on the antenna type, the ceiling height, and the RF environment.

Option C is incorrect because 802.11ac AP radios are not more sensitive to 2.4 GHz interference than 802.11n APs. In fact, 802.11ac APs operate in the 5 GHz band, which is less crowded and prone to interference than the 2.4 GHz band.

Option D is incorrect because 802.11ac APs cannot support a higher density of clients by being deployed farther apart. On the contrary, 802.11ac APs need to be deployed closer together to provide the higher data rates and throughput that 802.11ac clients expect.

References: The information can be referenced from the official HPE documents and learning materials available on HPE Press and Aruba Networks. Specifically, it aligns with the objectives outlined in Chapter 4: Wireless LAN Design, where the capacity-based design and site survey methods are discussed. Designing Aruba Solutions Official Certification Study Guide Aruba Mobility Fundamentals Guide