Explanation
The correct steps that are part of the Key Management workflow when a wireless device is roaming from AP1 to AP2 are A and D.
A: AP1 will cache the client's information and send it to the Key Management service. This is true because when a client associates and authenticates with AP1, AP1 will generate a pairwise master key (PMK) for the client and store it in its cache. AP1 will also send the PMK and other client information, such as MAC address, VLAN, and SSID, to the Key Management service, which is a centralized service that runs on Aruba Mobility Controllers (MCs) or Mobility Master (MM) devices1. The Key Management service will use this information to facilitate fast roaming for the client.
D: The Key Management service then generates R1 keys for AP2's neighbors. This is true because when the Key Management service receives the client information from AP1, it will use the PMK to derive R0 and R1 keys for the client. R0 keys are used to generate R1 keys, which are used to generate pairwise transient keys (PTKs) for encryption. The Key Management service will distribute the R1 keys to AP2 and its neighboring APs, which are determined by AirMatch based on RF proximity2. This way, when the client roams to AP2 or any of its neighbors, it can skip the 802.1X authentication and use the R1 key to quickly generate a PTK with the new AP3.
B: The Key Management service receives from AirMatch a list of all AP2's neighbors. This is false because the Key Management service does not receive this information from AirMatch directly. AirMatch is a feature that runs on MCs or MM devices and optimizes the RF performance of Aruba devices by using machine learning algorithms. AirMatch periodically sends neighbor reports to all APs, which contain information about their nearby APs based on signal strength and interference. The APs then send these reports to the Key Management service, which uses them to determine which APs should receive R1 keys for a given client2.
C: The Key Management service receives a list of all AP1 s neighbors from AirMatch. This is false for the same reason as B. The Key Management service does not receive this information from AirMatch directly, but from the APs that send their neighbor reports.
E: A client associates and authenticates with the AP2 after roaming from AP1. This is false because a client does not need to authenticate with AP2 after roaming from AP1 if it has already authenticated with AP1 and received R1 keys from the Key Management service. The client only needs to associate with AP2 and perform a four-way handshake using the R1 key to generate a PTK for encryption3. This is called fast roaming or
802.11r roaming, and it reduces the latency and disruption caused by full authentication.1: ArubaOS 8.7 User Guide 2: ArubaOS 8.7 User Guide 3: ArubaOS 8.7 User Guide : ArubaOS 8.7 User Guide

A). Have the installers generate keys with ClearPass Self Service Registration. - While this could theoretically work, it would require each installer to manually register each device. This can be cumbersome and time-consuming, especially given the number of devices in this scenario.
B). Have the MPSK gateway derive the unique pre-shared keys based on the MAC OUI. - This is not a typical feature of MPSK. MPSK can assign unique keys based on full MAC addresses, not just the MAC OUI (which only identifies the manufacturer and not individual devices).
C). Use MPSK Local to automatically provide unique pre-shared keys for devices. - MPSK Local can be set up to assign unique pre-shared keys based on MAC addresses, which would reduce administrative overhead. However, the "automatic" provision is somewhat misleading, as the keys and MAC addresses would still need to be predefined in the MPSK Local configuration.
D). MPSK Local will allow the cameras to share a key and the scanners to share a different key. - This is a valid use of MPSK. It would be less secure than giving each device its unique key (since all cameras would share one key and all scanners another), but it would reduce the administrative overhead considerably. This approach balances security and simplicity.
Given the primary goal of reducing IT administration overhead while still maintaining a relatively secure environment, the best answer would be:
D). MPSK Local will allow the cameras to share a key and the scanners to share a different key.

These are the correct requirements to ensure that WMM (Wi-Fi Multimedia) is working effectively. WMM is a standard that provides quality of service (QoS) for wireless networks by prioritizing traffic into four categories: voice, video, best effort, and background. To use WMM, both the APs and the controller must be Wi-Fi CERTIFIED for WMM, which means they have passed interoperability tests and comply with the standard. WMM must also be enabled on the APs and the controller, which is usually the default setting.
The client device must also be Wi-Fi CERTIFIED for WMM and configured for WMM marking, which means it can tag its traffic with the appropriate priority level based on the application type. The other options are incorrect because they are either not related to WMM or not required for WMM to work.
References:
https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/wlan- qos/wmm.h
https://www.wi-fi.org/discover-wi-fi/wi-fi-certified-wmm

The active gateway feature is used to provide active-active layer 3 default gateway for hosts on the same subnet. It allows the switch to convert multicast streams into unicast streams over the wireless link, which improves the quality and reliability of streaming video, while preserving the bandwidth available to the non-video clients. The active gateway feature is unique to VSX configuration because it eliminates the need for VRRP and avoids traffic being pushed over the ISL link, which can cause latency in the network12.
The correct answer to the question is C. Sixteen different VMACs are supported for each IPv4 and IPv6 stack simultaneously. This means that you can have a maximum of eight VMACs for IPv4, and a maximum of eight VMACs for IPv6, on a VSX pair. Only 15 VMACs are supported on 6400 switch series2.
The other options are incorrect because:
A) Sixteen different VMACs are not supported total as shared. They are supported for each IPv4 and IPv6 stack separately.
B) Active gateway can be used without MSTP instances. MSTP is a protocol that allows multiple spanning tree instances to coexist on the same switch, but it does not affect how active gateway works.
D) Active gateway does not copy traffic over the ISL link for an optimized path. It avoids using the ISL link for routed traffic and uses the local switch interface MAC instead of the virtual MAC address (VMAC) for source address1.

https://www.arubanetworks.com/techdocs/AOS-CX/10.07/HTML/5200-7885/Content/Chp_Mng_Use/bui-in- use-gro-the-pri-10.htm