HP Updated HPE6-A47 Exam Questions and Answers by orlando

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

Air Monitors (AMs) are Aruba access points (APs) that are configured to operate in a dedicated mode for scanning the RF spectrum and detecting rogue APs, clients, and intrusion attacks. AMs do not serve any wireless clients and can scan all channels in both 2.4 GHz and 5 GHz bands. AMs provide better visibility and coverage of the RF environment than APs that serve clients, as they can scan more frequently and thoroughly. However, AMs also consume more power and network resources than APs, and require additional hardware and licensing costs. Therefore, the optimal number of AMs per floor depends on several factors, such as the size and shape of the floor, the density and distribution of APs and clients, the security and compliance requirements, and the budget and availability of the organization.

According to the Aruba Wireless Intrusion Protection (WIP) Technology Guide1, a general rule of thumb is to deploy one AM for every four to six APs. This ratio can provide adequate coverage and detection for most environments, while balancing the trade-offs between performance and cost. However, this ratio is not fixed and can vary depending on the specific needs and characteristics of each deployment. For example, if the floor has a high density of APs and clients, or a high risk of rogue or malicious activity, more AMs may be needed to provide better security and visibility. Conversely, if the floor has a low density of APs and clients, or a low risk of rogue or malicious activity, fewer AMs may be sufficient to provide adequate security and visibility.

In this case, the floor has 20 APs, which implies a moderate to high density of APs and clients. Assuming that the floor has a rectangular shape and a uniform distribution of APs and clients, a reasonable estimate of the number of AMs per floor would be about 3 to 5, based on the general rule of thumb. This would provide enough coverage and detection for most scenarios, while minimizing the additional costs and resources. However, this estimate may need to be adjusted if the floor has a different shape or a non-uniform distribution of APs and clients, or if the organization has specific security and compliance requirements that demand more or less AMs per floor. References:

• Wireless Intrusion Protection (WIP) Technology Guide
• Installing Air Monitors | Wireless Access - Airheads Community
• Aruba Certified Design Professional Official Certification Study Guide (HPE6-A47)

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)

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