HP HPE6-A47 Designing Aruba Solutions Exam Practice Test

The guideline for defining another VLAN for wireless devices should be based on the employee roles, with a different VLAN for each role or department. This approach allows for better control and management of network resources. It also enhances security by segregating network traffic based on roles or departments. This is particularly useful in large organizations where different departments may have different network requirements and security levels12.

References:

• Configuring VLANs - Aruba
• TECH BRIEF SINGLE VLAN DESIGN FOR WIRELESS LAN - Aruba

References:

• 4: https://blog.router-switch.com/2020/11/data-center-design-basic-3-layers-core-aggregation-and-access/
• 1: https://community.cisco.com/t5/data-center-and-cloud-knowledge-base/datacenter-core-and-aggregation-design/ta-p/3135946
• 2: https://www.oreilly.com/library/view/ccna-data-center/9780133860429/ch01lev3sec2.html
• 3: https://www.arubanetworks.com/techdocs/ArubaOS_64x_WebHelp/Content/ArubaFrameStyles/VLANs/Extending_VLANs.htm

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/

 The correct answer is option C, conversion of the existing Instant APs to campus APs (CAPs). This is because the existing Instant APs can be converted to CAPs by changing their operating mode and pointing them to the MC. This way, the customer can leverage the existing APs and avoid purchasing new ones. The MC can then provide centralized management, configuration, and control for the APs.

Option A is incorrect because the purchase of Universal APs is not necessary. Universal APs are APs that can operate in either Instant or CAP mode without requiring a conversion. However, the existing APs can be converted to CAPs without buying new ones.

Option B is incorrect because Aruba ClearPass is not required to onboard the APs as CAPs in the new MC-based deployment. Aruba ClearPass is a network access control (NAC) solution that provides authentication, authorization, and accounting (AAA) services for wired and wireless devices. It is not involved in the conversion of Instant APs to CAPs.

Option D is incorrect because a Virtual Mobility Controller (VMC) is not a valid option to control Instant APs. A VMC is a software-based MC that runs on a hypervisor. It can control CAPs, but not Instant APs. Instant APs can only be controlled by another Instant AP acting as a Virtual Controller (VC).

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 6: Wireless Network Design, where the Instant and CAP modes and the MC options are discussed. Designing Aruba Solutions Official Certification Study Guide Aruba Instant User Guide Aruba Mobility Controller Data Sheet

The switch needs to support PoE+ for this deployment. PoE+ stands for Power over Ethernet Plus, and it is a technology that allows the switch to provide both data and power to the connected devices over a single Ethernet cable. This eliminates the need for separate power sources or adapters for the devices, and simplifies the installation and management of the network. PoE+ can provide up to 30 watts of power per port,which is sufficient for the Aruba 320 Series APs, which have a maximum power consumption of 20 watts. PoE+ also supports 1 GbE connectivity, which meets the customer’s requirement.

The other options are not relevant for this deployment:

• Option B is incorrect because LACP is not a feature that the switch needs to support for this deployment. LACP stands for Link Aggregation Control Protocol, and it is a protocol that allows multiple physical links to be combined into a single logical link, providing higher bandwidth and redundancy. However, the architect plans to connect each AP with one Ethernet port to the switch, so there is no need for link aggregation in this scenario.
• Option C is incorrect because port channel is not a feature that the switch needs to support for this deployment. Port channel is another term for link aggregation, which is not required for this scenario, as explained above.
• Option D is incorrect because Smart Rate is not a feature that the switch needs to support for this deployment. Smart Rate is a technology that allows the switch to provide multi-gigabit Ethernet speeds (up to 10 GbE) and PoE+ to the connected devices, depending on the cable type and length. However, the customer only wants to support at least 1 GbE connectivity, which can be achieved with PoE+ and CAT6 cable, without the need for Smart Rate.

References:

• Aruba 320 Series Access Points Data Sheet)
• ArubaOS-Switch and ArubaOS-CX Transceiver Guide)
• Aruba Certified Design Professional Official Certification Study Guide (HPE6-A47))

 Aruba AirWare is a network management solution that provides real time statistics and assessment of call quality for Skype for Business UC solution. It integrates with Skype for Business SDN API to monitor and troubleshoot voice and video calls, and optimize network performance and user experience. It also provides visibility into network health, application performance, and user behavior across wired and wireless networks. Aruba Central is a cloud-based network management solution that does not support Skype for Business integration. Aruba Mobility Master (MM) is a network controller that manages Aruba access points and switches, but does not provide call quality statistics or assessment. Aruba ClearPass is a network access control solution that provides secure authentication and policy enforcement, but does not monitor or optimize Skype for Business calls. References: Aruba AirWave Network Management), Aruba AirWave and Microsoft Skype for Business Integration Guide)

 This answer is correct because it meets the customer’s requirements for wired authentication and traffic forwarding. By assigning wired users to different VLANs from wireless users, the architect can ensure that the wired traffic is not tunneled to the MCs, but forwarded locally on the access layer switches. This reduces the load on the MCs and the network bandwidth. By using port or role assignments on the access layer switches, the architect can also implement 802.1X authentication without tunnelled node, which enables user access control and dynamic VLAN assignment based on user identity and device type. By extending the VLANs to the core, the architect can ensure that the wired users can reach the data center and other network resources through the Layer 3 switch connected to the firewall. References:

• Aruba 2930M Switch Series - Data sheet)
• Aruba ClearPass Policy Manager - Data sheet)
• ArubaOS-Switch Wired Access with ClearPass - Configuration guide)

 In local mode, the IAP cluster at the branch office has a local subnet and the master IAP of the cluster acts as the DHCP server and gateway for clients. The local mode provides access to the corporate network using the inner IP of the IPsec tunnel. The local mode is recommended for this scenario because it allows the branch office to remain functional even if the link to the main office fails, as the clients can still obtain IP addresses and access local resources. The local mode also avoids the need for additional routing or switching configuration on the MC or the branch office network12. References:

• 1: Understanding IAP-VPN Architecture - Aruba
• 2: IAP-VPN Forwarding Modes - Aruba

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.

 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)]

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

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

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)

According to the Aruba documentation, Aruba AirWare Clarity is a feature that proactively analyzes end-users’ quality of experience by providing enhanced monitoring capabilities for critical network services, such as time and response failures for a mobile device to associate with a Wi-Fi radio, authenticate to a RADIUS server, obtain an IP address through DHCP, and resolve names for DNS services. This gives IT staff end-to-end visibility into problems before they escalate as metrics are monitored in real-time, and also captured through on-demand or scheduled testing for predictive insight. By assessing the times for clients to obtain DHCP and DNS services, Clarity helps staff diagnose non-WiFi related issues that may affect the network performance and user experience.

References:

• Clarity - Aruba
• Clarity - Aruba

802.1X authentication without tunnelled node is a form of port-based network access control that uses the Extensible Authentication Protocol (EAP) to authenticate users and devices on a wired network. This form of authentication provides several benefits, such as:

• It enables user access control and ensures only authorized users connect. This prevents unauthorized access to the network and its resources, and enhances security and compliance.
• It allows dynamic assignment of VLANs and roles based on user identity and device type. This simplifies network management and improves user experience.
• It supports multiple authentication methods, such as certificates, passwords, tokens, or biometrics. This provides flexibility and choice for users and administrators.
• It integrates with Aruba ClearPass Policy Manager (CPPM) for centralized policy enforcement and visibility. This enables granular control and monitoring of wired user traffic and devices. References:
• Aruba 2930M Switch Series - Data sheet)
• Aruba ClearPass Policy Manager - Data sheet)
• ArubaOS-Switch Wired Access with ClearPass - Configuration guide)

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

The traditional guideline limits a wired VLAN to a /24 subnet, which provides enough IP addresses for 253 endpoints. You might have suggested one of three approaches: one VLAN per floor, one VLAN per building, or one VLAN per campus. The one VLAN per floor approach is not recommended because it interferes with roaming and adds complexity. If you did take this approach, the /24 subnets are not large enough for the requirements on every floor. You would need to ask for /23 subnets. The one VLAN per building approach would work if you considered each building its own RF domain. It provides roaming within a building and, if you are using a single cluster at the data center, between buildings. Ifyou deployed two MCs or clusters, one at each building, though, GRE tunneling would be required to support roaming between buildings.

 To ensure that wireless voice traffic is properly prioritized for Microsoft Skype for Business, the architect should set up firewall policies and SDN to mark voice on the MCs or MM. Firewall policies are used to classify and prioritize traffic based on the application, user role, device type, and location. SDN is used to integrate with the Skype for Business SDN API, which provides real-time information about voice and video sessions, such as source and destination IP addresses, ports, codecs, and quality metrics. By using firewall policies and SDN, the MCs or MM can dynamically mark voice traffic with the appropriate DSCP values and queue them in the highest priority queue on the wireless and wired network12.

The other options are not sufficient or relevant for ensuring wireless voice traffic prioritization for Skype for Business. Broadcast suppression combined with AirGroup is used to reduce the network overhead and improve the user experience for wireless devices that use multicast or broadcast protocols, such as Apple Bonjour or Microsoft UPnP3. Airtime Fairness set to fair-access is used to balance the airtime usage among clients with different capabilities and data rates, such as 802.11ac and 802.11n4. Voice-aware Layer 3 roaming is used to enable seamless handoff of voice sessions across different subnets without dropping the call5. While these features may enhance the overall wireless performance and reliability, they do not directly prioritize voice traffic for Skype for Business.

References:

• Aruba Validated Reference Design: 802.11ac Networks
• Aruba Validated Reference Design: Skype for Business
• Aruba Validated Reference Design: AirGroup
• Aruba Validated Reference Design: Adaptive Radio Management
• Aruba Validated Reference Design: Voice over Wireless LAN

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