Explanation
EVPN-VXLAN is a technology that allows layer-2 communication across layer-3 networks by using Ethernet VPN (EVPN) as a control plane and Virtual Extensible LAN (VXLAN) as a data plane3. EVPN-VXLAN can be used to support legacy applications that communicate at layer-2 across different campuses or data centers that are connected via layer-3. EVPN-VXLAN minimizes flooding by using BGP to distribute MAC addresses and IP addresses of hosts across different VXLAN segments3. EVPN-VXLAN also provides benefits such as loop prevention, load balancing, mobility, and scalability3. References: 3
https://www.arubanetworks.com/assets/tg/TG_EVPN_VXLAN.pdf

PAPI is the protocol that is used to establish tunnels between the CX switch and the Aruba Gateway for Dynamic Segmentation1. By default, PAPI uses a simple checksum to verify the integrity of the messages, but it does not encrypt the payload2. This could expose the network to spoofing or replay attacks by malicious actors. To address this situation, the administrator must enable Enhanced PAPI security, which uses AES-256 encryption and HMAC-SHA1 authentication to protect the tunnel traffic2. Enhanced PAPI security can be enabled on the CX switch by using the command system papi enhanced-security enable3. This will ensure that the tunnels built between the CX switch and the Aruba Gateway are encrypted and authenticated.

* Client IP address: This factor can be used to determine if the client is on the same VLAN as the AP or not. If the client IP address is on the same VLAN as the AP, then the client traffic is bridged locally. If the client IP address is on a different VLAN than the AP, then the client traffic is forwarded to the gateway cluster through a secure tunnel 12.
* Client VLAN: This factor can be used to determine if the client belongs to a specific VLAN or not. If the client belongs to a specific VLAN, then the client traffic is forwarded to that VLAN based on its IP address and security profile 12.

Explanation
Encryption is a feature supported by SNMPv3 that provides an advantage over SNMPv2c. Encryption protects the confidentiality and integrity of SNMP messages by encrypting them with a secret key. SNMPv2c does not support encryption and relies on community strings for authentication and authorization, which are transmitted in clear text and can be easily intercepted or spoofed. Transport mapping, community strings, and GetBulk are features that are common to both SNMPv2c and SNMPv3. References:
https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/snmp/snmp.htm
https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/snmp/snmpv3.htm

The reason is that the Inter-Switch Link Protocol (ISLP) is a protocol that enables VSX stack join and synchronization between two VSX peer switches. ISLP uses a hello interval to exchange control messages between the switches.
The hello interval is a parameter that specifies the time interval between sending hello messages. The default value of the hello interval is 1 second. The hello interval can be configured from 1 second to 10 seconds.
https://www.arubanetworks.com/techdocs/AOS-CX/10.04/HTML/5200-6728/index.html