HPE6-A47 Designing Aruba Solutions Questions and 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

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

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.

The Aruba 2930F Switch Series is a stackable Layer 3 switch series that provides performance and ease of use for enterprises, small and medium-sized businesses, and branch office networks1. It comes with an enterprise-grade feature set that includes static and RIP routing, IPv6, ACLs, robust security, and QoS1. The 2930F Series supports more options for class-based Quality of Service (QoS) policies than the 2540 Series2. This feature is crucial for a customer who needs a wired network solution that can recognize and prioritize a wide array of different types of traffic, including casual Web browsing, voice, video, SAP Online, and file sharing.

References:

• HPE Aruba Networking 2930F Switch Series
• Why would the architect choose the 2930F rather than the 2540 Switch Series for this customer?

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)

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 Aruba MC 7010 and 7024 are both designed for small to mid-sized campuses and branches, but they have some differences in their features and specifications. One of the main differences is the number and type of ports they offer. The MC 7010 has 16 10/100/1000BASE-T ports, while the MC 7024 has 8 10/100/1000BASE-T ports and 8 1000BASE-X SFP ports1. This means that the MC 7024 can support more APs that require fiber connections, such as the AP-387 or the AP-5352. The MC 7024 also supports 10G ports, which can provide higher bandwidth and performance for the network backbone3.

Therefore, if the customer needs to connect 20 APs directly to the MC, and some of them require fiber or 10G connections, the MC 7024 is a better choice than the MC 7010. The other options (A, B, and C) are not relevant for choosing between the MC 7010 and 7024, as both models can support up to 64 APs and 4096 users or devices, and both models can provide PoE+ on 12 ports1.

References:

• Aruba 7000 Series Mobility Controllers Data Sheet
• Aruba Access Points Data Sheet
• Aruba 7000 Series Mobility Controllers and Gateways

DSCP (Differentiated Services Code Point) is a method of marking network packets with different priorities based on the type of traffic they carry. DSCP values range from 0 to 63, with higher values indicating higher priority. DSCP values are typically mapped to one of the four WMM (Wi-Fi Multimedia) queues, which are used to prioritize wireless traffic on the access points and controllers. WMM queues are: voice, video, best effort, and background12.

The default QoS settings for Aruba APs and controllers map the DSCP values to the WMM queues as follows3:

Table

DSCP Value

WMM Queue

0-7

Background

8-23

Best Effort

24-39

Video

40-63

Voice

According to these settings, the DSCP values 46 and 34, which are assigned to voice and video traffic by Windows policies, will both be mapped to the video WMM queue. This means that both types of traffic will receive the same priority, and voice traffic will not receive the highest priority that it should. This can result in poor voice quality, increased latency, jitter, or packet loss, especially when the network is congested or bandwidth is limited. Voice traffic is more sensitive to these factors than video traffic, and requires strict QoS to ensure optimal performance and user experience4.

To avoid this potential issue, the architect should explain to the customer that they need to modify the QoS settings on the Aruba APs and controllers to match the DSCP values assigned by Windows policies. This can be done by using the following commands on the Aruba controller3:

(config) #wmm traffic-management-profile voice

(config) #dscp 46

(config) #wmm traffic-management-profile video

(config) #dscp 34

These commands will map the DSCP value 46 to the voice WMM queue, and the DSCP value 34 to the video WMM queue, ensuring that voice traffic receives the highest priority and video traffic receives the second highest priority. This will improve the QoS for the Skype for Business UC solution and enhance the end-user experience.

References:

• 1: https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/1-overview/qos.htm
• 2: https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/1-overview/wmm.htm
• 3: https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/1-overview/qos-mapping.htm
• 4: https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/1-overview/qos-voice.htm

The frequency of the radio wave is one of the most important factors that determines the antenna performance and compatibility. The antenna must be designed to operate at the same frequency band as the radio, otherwise the impedance mismatch will cause signal loss and reflection. The frequency also affects the size, shape, and radiation pattern of the antenna. For example, a lower frequency requires a larger antenna to achievethe same gain and directivity as a higher frequency antenna. The frequency also determines the available bandwidth and channel spacing for the wireless communication12. Therefore, it is essential to ensure that the antenna is designed for the frequency used by the radio. References:

• 1: Antenna selection guidelines - STMicroelectronics
• 2: Guide to Selecting the Right Antenna - Telco Antennas

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

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)

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

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.

Aruba Central Managed Portal (MSP) is a cloud-based network management platform that enables service providers to centrally manage and monitor multiple tenant accounts from a single interface1. MSP mode is a multi-tenant operational mode that Aruba Central accounts can be converted into, provided these accounts have subscribed to the Aruba Central app2. MSP mode allows service providers to provision and manage tenant accounts, assign devices to tenant accounts, manage subscription keys and perform other functions such as configuring network profiles and viewing alerts3. MSP mode is suitable for the scenario where a service provider needs to manage multiple customer networks, as it simplifies tenant network operations using capabilities such as zero-touch setup, historical data reporting, PCI compliance monitoring, and troubleshooting2. References:

• 1: MSP Overview - Aruba
• 2: MSP Architecture - Aruba
• 3: Managed Service Portal - Aruba

This answer is correct because it matches the scenario for which the Aruba backplane stacking technology is designed. Aruba backplane stacking technology allows up to 10 switches to be interconnected using high-speed backplane cables, creating a single logical device with a single IP address and configuration. This simplifies the management and operation of the network, as well as the redundancy design, as the stack can operate in ring or chain topology and provide fast failover in case of link or switch failure. This technology is suitable for customers who need to deploy a pair of aggregation switches in the same closet, as it reduces the number of devices and links to manage, and provides high availability and scalability for the network.

The other options are incorrect because:

• B. The customer needs to simplify the deployment of core switches which are located in different closets for redundancy purposes. This scenario is not suitable for Aruba backplane stacking technology, as it requires the switches to be physically close to each other and connected with backplane cables. A better option for this scenario would be to use Aruba Virtual Switching Framework (VSF) technology, which allows up to twoswitches to be interconnected using standard Ethernet links, creating a virtual switch that can span across different closets or racks.
• C. The customer needs to expand the network and make it possible for the current core switches to support more MAC forwarding and ARP entries. This scenario is not suitable for Aruba backplane stacking technology, as it does not increase the MAC or ARP table size of the switches. The MAC and ARP table size is determined by the hardware specifications of each switch model, and stacking them together does not change that. A better option for this scenario would be to upgrade the core switches to a higher-end model that supports more MAC and ARP entries, or to segment the network into smaller subnets to reduce the MAC and ARP traffic.
• D. The customer needs to deploy a switch at a branch office and have the switch automatically discover and join the network stack at the main office. This scenario is not suitable for Aruba backplane stacking technology, as it requires the switches to be on the same LAN and connected with backplane cables. A better option for this scenario would be to use Aruba Central, which is a cloud-based management platform that allows remote provisioning and monitoring of Aruba switches and other devices. Aruba Central can automatically discover and join the switch to the network, and apply the configuration and policies from the main office.

References:

• Aruba 2930M Switch Series - Data sheet)
• ArubaOS-Switch Virtual Switching Framework - Configuration guide)
• Aruba Central - Data sheet)