HPE6-A47 Sample Questions Answers

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

Clustering is a feature that allows multiple Aruba MCs to work together as a single logical entity to provide high availability, scalability, and mobility for wireless clients12. One of the main benefits of clustering is that it provides wireless client load balancing and seamless failover for client sessions. This means that:

• Wireless clients are distributed evenly among the cluster members based on the available resources and the configured load balancing algorithm12. This helps to optimize the network performance and avoid congestion or bottlenecks.
• Wireless clients remain connected to the same MC, called the Active AP Anchor Controller (A-AAC), throughout their roaming area within the cluster, regardless of which AP they are associated with12. This ensures that the clients retain their IP address, subnet, and session information, and do not experience any disruption or delay in their connectivity or applications.
• Wireless clients can seamlessly fail over to another MC, called the Standby AP Anchor Controller (S-AAC), in case of a failure or maintenance of their A-AAC12. The S-AAC takes over the client sessions and state information from the A-AAC without requiring any re-authentication or re-association from the clients. This minimizes the impact of the failure and provides high availability and resiliency for the wireless services.

Therefore, by explaining these benefits, the architect can demonstrate how clustering can meet the customer’s high availability requirements for wireless services.

References:

• 1: https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/cluster/clus-over.htm
• 2: https://www.arubanetworks.com/techdocs/ArubaOS_85_Web_Help/Content/arubaos-solutions/cluster/clus-over.htm

A cluster is a group of MCs that work together to provide high availability, seamless roaming, and load balancing for wireless clients and APs. A cluster requires all MCs to be on the same VLAN and subnet, and to have the same software version and configuration. A cluster supports stateful failover for user connections, which means that if an MC fails, the user sessions are preserved and transferred to another MC in the cluster without any disruption. A cluster also supports hitless failover for APs, which means that if an MC fails, the APs that were connected to it automatically join another MC in the cluster without rebooting. A cluster is the recommended design for high availability for wireless services12. References:

• 1: Cluster Overview - Aruba
• 2: High Availability (SSO) Deployment Guide - Cisco

 A collision domain is a logical area of the network where devices share the same wireless medium and may interfere with each other’s transmissions. In a WLAN, a collision domain is defined by the channel and the coverage area of an AP or a client. Devices that operate on the same channel and are within range of each other belong to the same collision domain and must contend for access to the medium using the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol. Devices that operate on different channels or are out of range of each other belong to different collision domains and do not interfere with each other.

In this scenario, the architect plans 12 APs for an auditorium that is 325 square meters (3,498 square feet). Each AP has one 2.4 GHz radio and one 5 GHz radio. Both types of radios use 20 MHz channels. Assuming that DFS channels can be used in this design, the question is how many 5 GHz collision domains does this design provide.

To answer this question, we need to consider the following factors:

• The number of available 5 GHz channels in the regulatory domain of the auditorium. Different countries have different regulations on the use of the 5 GHz band, which affects the number and availability of channels for WLANs. For example, in the United States, there are 25 non-overlapping 20 MHz channels in the 5 GHz band, but some of them are subject to Dynamic Frequency Selection (DFS) requirements, which means that they must avoid interfering with radar systems by detecting and switching to another channel if radar signals are present. In other countries, such as Japan, there are 19 non-overlapping 20 MHz channels in the 5 GHz band, but some of them are restricted to indoor use only. Therefore, the number of available 5 GHz channels for the design depends on the regulatory domain of the auditorium.
• The channel assignment and distribution of the 12 APs in the auditorium. The channel assignment and distribution of the APs affect the number and size of the collision domains in the WLAN. Ideally, the APs should be assigned to non-overlapping channels and distributed evenly across the auditorium to provide optimal coverage and capacity, while minimizing co-channelinterference and adjacent channel interference. Co-channel interference occurs when devices on the same channel interfere with each other, while adjacent channel interference occurs when devices on nearby channels interfere with each other. Both types of interference degrade the performance and quality of the WLAN. Therefore, the channel assignment and distribution of the APs should follow the best practices of RF design, such as using a channel reuse plan, avoiding channel overlap, and adjusting the transmit power and antenna gain of the APs to match the coverage and capacity requirements of the auditorium.
• The coverage and capacity requirements of the auditorium. The coverage and capacity requirements of the auditorium affect the number and placement of the APs and the transmit power and antenna gain settings of the radios. The coverage requirement refers to the minimum signal strength and signal-to-noise ratio (SNR) that the APs and clients need to maintain a reliable wireless connection. The capacity requirement refers to the maximum number of clients and the minimum throughput and quality of service (QoS) that the APs and clients need to support the applications and services of the auditorium. The coverage and capacity requirements of the auditorium depend on the size and shape of the space, the density and distribution of the clients, the types and characteristics of the applications and services, and the performance and capabilities of the devices. Therefore, the coverage and capacity requirements of the auditorium should be determined by conducting a site survey and a network analysis, and then used to guide the design and configuration of the APs and radios.

Based on these factors, we can estimate the number of 5 GHz collision domains in the design as follows:

• Assuming that the auditorium is located in the United States and that DFS channels can be used in the design, there are 25 non-overlapping 20 MHz channels in the 5 GHz band. However, not all of them may be available or suitable for the design, depending on the presence and activity of radar systems in the area, the compatibility and support of the APs and clients, and the interference and noise level of the environment. Therefore, we will use a conservative estimate of 15 available 20 MHz channels in the 5 GHz band for the design.
• Assuming that the 12 APs are assigned to non-overlapping channels and distributed evenly across the auditorium, each AP will have its own 5 GHz collision domain, as there will be no co-channel interference or adjacent channel interference among the APs. Therefore, there will be 12 5 GHz collision domains in the design, corresponding to the 12 APs.
• Assuming that the coverage and capacity requirements of the auditorium are moderate and that the transmit power and antenna gain settings of the radios are adjusted accordingly, each AP will cover an area of about 27 square meters (290 square feet), which is roughly the size of a small classroom. This means that the APs will provide adequate signal strength and SNR for the clients, while avoiding excessive overlap and interference among the APs. Therefore, there will be no need to further divide or merge the 5 GHz collision domains in the design, as they will match the coverage and capacity requirements of the auditorium.

Hence, the number of 5 GHz collision domains in the design is 12, which is the answer option C. References:

• RF Design | Validated Solution Guide - Aruba
• Configuring 2.4 Ghz and 5 Ghz Radios - Aruba
• Chapter T-5: Understanding RF Collision Domains - Aruba
• [Aruba Certified Design Professional Official Certification Study Guide (HPE6-A47)]

The Aruba SDN Controller is a software component that runs on the Mobility Master (MM) and provides centralized control and management of the network devices and applications that support the SDN services. The SDN Controller communicates with the network devices through the southbound interface (SBI) and exposes the northbound API (NBAPI) for the SDN applications to access the network resources and services1.

One of the SDN applications that can integrate with the Aruba SDN Controller is the Aruba UC and Collaboration Solution, which optimizes the performance and quality of Skype for Business traffic over the wireless network. The Aruba UC and Collaboration Solution consists of three components: the Aruba UC and Collaboration SDN Application, the Aruba UC and Collaboration Dashboard, and the Aruba UC and Collaboration Agent2.

The Aruba UC and Collaboration SDN Application is a software module that runs on the Skype for Business Front End Server and communicates with the Aruba SDN Controller through the NBAPI. The Aruba UC and Collaboration SDN Application monitors the Skype for Business sessions and events, and sends the relevant information to the Aruba SDN Controller, such as the user identity, device type, session type, codec, bandwidth, and quality of service (QoS) requirements2.

The Aruba UC and Collaboration Dashboard is a web-based graphical user interface that provides visibility and analytics of the Skype for Business sessions and events over the wireless network. The Aruba UC and Collaboration Dashboard connects to the Aruba SDN Controller through the NBAPI and displays the information collected by the Aruba UC and Collaboration SDN Application, such as the number of active sessions, session types, session quality, bandwidth consumption, and device distribution2.

The Aruba UC and Collaboration Agent is a software module that runs on the Mobility Controller (MC) and communicates with the Aruba SDN Controller through the SBI. The Aruba UC and Collaboration Agent receives the information from the Aruba UC and Collaboration SDN Application through the Aruba SDN Controller, and applies the appropriate QoS policies and actions on the wireless network, such as prioritizing the Skype for Business traffic, marking the DSCP values, reserving the bandwidth, and adjusting the airtime2.

To support high availability for the SDN services, the Aruba SDN Controller must be deployed in a redundant configuration, with a primary MM and a backup MM. The primary MM runs the active instance of the Aruba SDN Controller, while the backup MM runs the standby instance of the Aruba SDN Controller. The backup MM synchronizes the configuration and state information from the primary MM, and takes over the SDN Controller role in case of a failure or switchover of the primary MM1.

The other options do not provide high availability specifically for the SDN services, although they may provide redundancy for other aspects of the wireless network. A redundant master MC does not run the Aruba SDN Controller, and only provides backup for the master MC role, which is responsible for managing the configuration and licensing of the MCs in the network3. Backup controllers defined on the APs do not run the Aruba SDN Controller, and only provide backup for the local MC role, which is responsible for terminating and managing the APs in the network4. A cluster deployment for MCs does not run the Aruba SDN Controller, and only provides load balancing and fast failover for the APs in the network5.

References: 1: ArubaOS 8.7 User Guide - Aruba, Chapter 42: SDN Controller, pages 1049-1050. 2: Aruba UC and Collaboration Solution Guide - Aruba, Chapter 2: Aruba UC and Collaboration Solution Overview, pages 11-15. 3: ArubaOS 8.7 User Guide - Aruba, Chapter 2: ArubaOS Architecture, pages 25-26. 4: ArubaOS 8.7 User Guide - Aruba, Chapter 3: Configuring Controller Redundancy, pages 39-40. 5: ArubaOS 8.7 User Guide - Aruba, Chapter 4: Configuring Controller Clustering, pages 51-52.

The architect should follow the guideline of assigning access layer switches IP addresses on a VLAN that is dedicated for switch management. This is a best practice for network management security, as it isolates the switch management traffic from the data traffic, and prevents unauthorized access to the switches. A dedicated VLAN for switch management also simplifies the configuration and monitoring of the switches, and reduces the risk of broadcast storms or VLAN hopping attacks.

The other options are not best practices for network management security:

• Option B is incorrect because enabling DHCP on only the switch Default VLAN is not a secure way of assigning IP addresses to the switches. DHCP stands for Dynamic Host Configuration Protocol, and it is a protocol that automatically assigns IP addresses and other network parameters to devices on a network. However, DHCP can be vulnerable to spoofing or hijacking attacks, where an attacker can impersonate a DHCP server or client, and obtain or alter the network configuration. Moreover, using the Default VLAN for switch management is not recommended, as it is the VLAN that is assigned to all ports by default, and it can be easily accessed by anyone on the network.
• Option C is incorrect because enabling Telnet and setting it to listen on production VLANs is not a secure way of accessing the switches. Telnet stands for Telecommunication Network, and it is a protocol that allows remote login and command execution on a network device. However, Telnet is an insecure protocol, as it sends data in plain text, without any encryption or authentication. This means that anyone who can intercept the network traffic can read or modify the data, and gain unauthorized access to the switches. Moreover, using production VLANs for switch management is not recommended, as it exposes the switch management traffic to the data traffic, and increases the attack surface of the network.
• Option D is incorrect because assigning switches static IP addresses on the same VLAN on which APs are deployed is not a secure way of managing the switches. Static IP addresses are fixed IP addresses that are manually configured on a device, and they do not change unless they are changed by the administrator. However, static IP addresses can be prone to human errors, misconfiguration, or duplication, and they can be difficult to manage and update. Furthermore, using the same VLAN for switch management and AP deployment is not recommended, as it mixes the switch management traffic with the wireless traffic, and creates unnecessary overhead and security risks.

References:

• ArubaOS-Switch Management and Configuration Guide for WC.16.10)
• ArubaOS-Switch Basic Operation Guide for 16.10)
• Aruba Certified Design Professional Official Certification Study Guide (HPE6-A47))

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

 Aruba Instant APs are a simple, easy to deploy, and cost-effective solution for small office buildings that need wireless access. Aruba Instant APs can form a self-organizing and self-healing mesh network that supports basic rogue AP detection and provides a stateful firewall with role-based policies. Aruba Instant APs do not require a separate controller or license, and can be managed from the cloud or a mobile app. Aruba remote APs are designed for branch or home offices that need to connect to a central controller over a WAN link. Aruba campus APs and a Virtual Mobility Controller are suitable for larger or more complex deployments that need more scalability and flexibility. Aruba campus APs and an Aruba 7005 Mobility Controller are also more expensive and require additional hardware and licensing. References: Aruba Instant Access Points), Aruba Validated Design: Campus Wireless LAN)

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

 The correct answer is option C, voice. Voice applications have the greatest potential impact on RF design because they are sensitive to latency, jitter, and packet loss. Voice applications also require a minimum signal strength and signal-to-noise ratio to ensure good voice quality. Therefore, an architect needs to consider the number of voice devices, the codec used, the roaming behavior, and the call admission control when planning the RF coverage for voice applications. 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 3: Wireless LAN Technologies and Standards, where the RF design considerations for voice applications are discussed. Designing Aruba Solutions Official Certification Study Guide Aruba Mobility Fundamentals Guide

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

Auditoriums are challenging environments for wireless design, as they often have a large number of users and devices in a relatively small area, creating high demand for bandwidth and capacity. To provide adequate RF coverage and performance, auditoriums typically require a high-density AP design, which involves deploying more APs than usual, using directional antennas, reducing transmit power, and selecting non-overlapping channels12. A high-density AP design can also help mitigate interference from other sources, such as Bluetooth devices, which operate in the 2.4 GHz band3. Auditoriums do not necessarily require the use of 80 MHz channels or DFS channels, as these options depend on the availability and regulation of the spectrum, as well as the trade-off between throughput and channel reuse . References:

• 1: High Density Wi-Fi Design Principles - Aruba
• 2: Auditorium | WBDG - Whole Building Design Guide
• 3: Bluetooth and Wi-Fi Coexistence Issues and Solutions for the 2.4 GHz ISM Band - Aruba
• [4]: 802.11ac Channel Planning - Aruba
• [5]: Dynamic Frequency Selection (DFS) - Aruba

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

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

The IRIS BOM is missing stacking modules and cables for the Aruba 2930M switches. The customer wants to flatten the architecture and avoid recabling, but also maintain connectivity to the core if one link fails. To achieve this, the architect proposed to combine the switches in each Building 2 closet as a VSF fabric and establish two 10 GbE connections to the core per fabric. However, to create a VSF fabric, the switches need to have stacking modules and cables to interconnect them. The IRIS BOM does not include these items, which are required for the VSF configuration. The part numbers for the stacking modules and cables are JL325A and J9735A, respectively.

The other options are not missing from the IRIS BOM because they are either not required or already included. Stacking licenses are not required for the Aruba 2930M switches, as they support VSF natively. 10 GbE direct attach cables are already included in the IRIS BOM as part number J9283D. An uplink module for one of the switches is not required, as the customer already has enough fiber strands to connect each switch to the core. References:

• Aruba 2930M Switch Series Data Sheet (Aruba Networks)
• Designing Aruba Solutions Study Guide (HPE Press)

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)