Which two protocols are used for fabric discovery in ACI? (Choose two.)

LLDP (Link Layer Discovery Protocol) is a key protocol used by Cisco ACI for fabric discovery, as it enables switches to discover neighboring devices and exchange device capabilities and information over a local area network. ACI leverages LLDP to identify directly connected spine and leaf switches during the initial fabric bring-up process, allowing the APIC to build a topology map.

OSPF (Open Shortest Path First) is a routing protocol used for exchanging routing information within an IP network, not for initial fabric discovery in ACI.

CDP (Cisco Discovery Protocol) is a Cisco-proprietary protocol similar to LLDP, but ACI specifically uses LLDP for standards-based discovery.

DHCP (Dynamic Host Configuration Protocol) plays a crucial role in ACI fabric discovery by providing IP addresses to the switches during the initial boot-up and registration process. Each switch obtains an out-of-band management IP address via DHCP, which the APIC then uses to communicate with and onboard the switch into the fabric.

ISIS (Intermediate System to Intermediate System) is an interior gateway routing protocol, not involved in the initial physical fabric discovery process of ACI switches.