Which description regarding the initial APIC cluster discovery process is true?
A. The APIC uses an internal IP address from a pool to communicate with the nodes.
B. Every switch is assigned a unique AV by the APIC.
C. The APIC discovers the IP address of the other APIC controllers by using Cisco Discovery Protocol.
D. The ACI fabric is discovered starting with the spine switches.
The APIC discovers the IP address and node information of other Cisco APIC controllers in the cluster using the Link Layer Discovery Protocol (LLDP)-based discovery process. So C. CDP is NOT CORRECT.
ACI fabric is discovered starting with the directly attached LEAF SWITCH. So D. is NOT CORRECT
I believe the APIC internal IP address is assigned during bootup sequence which you must input manually at the prompt. Not from a pool. So A is not correct.
I think B. is the correct answer. AV is assigned to each switch from the APIC per below:
https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/1-x/aci-fundamentals/b_ACI-Fundamentals/b_ACI-Fundamentals_chapter_010011.html
The following describes the APIC cluster discovery process:
Each APIC in the Cisco ACI uses an internal private IP address to communicate with the ACI nodes and other APICs in the cluster. The APIC discovers the IP address of other APIC controllers in the cluster through the LLDP-based discovery process.
APICs maintain an appliance vector (AV), which provides a mapping from an APIC ID to an APIC IP address and a universally unique identifier (UUID) of the APIC. Initially, each APIC starts with an AV filled with its local IP address, and all other APIC slots are marked as unknown.
When a switch reboots, the policy element (PE) on the leaf gets its AV from the APIC. The switch then advertises this AV to all of its neighbors and reports any discrepancies between its local AV and neighbors’ AVs to all the APICs in its local AV.