The mapping and resolving of endpoints require a control plane protocol, and SD-Access uses Locator/ID Separation Protocol (LISP) for this task.

LISP brings the advantage of routing based NOT ONLY on the IP address or MAC address as the endpoint identifier (EID) for a device BUT ALSO on an additional IP address that it provides as a Routing Locator (RLOC) to represent the network location of that device.

Short Tips:

-The forwarding information base (FIB) is the actual information that a routing/switching device uses to choose the interface that a given packet will use for egress.

-Each FIB is programmed by one or more routing information bases (RIB). The RIB is a selection of routing information learned via static definition or a dynamic routing protocol. 

-RIB is derived from the control plane, it is not used for forwarding. Every protocol such as OSPF, EIGRP, BGP has its own RIB and select their best candidates to try to install to global RIB so that it can then be selected for forwarding

-Too much jitter can degrade the quality of voice and video communication.

-The network may be experiencing generalized issues, such as saturated bandwidth, high latency or packet loss, that are affecting all traffic.

Reasons:

Control plane nodes act as the network fabric’s traffic controllers and direct traffic between the edge nodes.

It runs a host tracking database to map location information and Endpoint IDs to the location it needs.

Once Border and Edge nodes send registration information to the control plane, the control plane node processes each resolution request to send Endpoint IDs to the requested/designated location.

Cisco SD-WAN devices advertise their local routes to the Cisco vSmart Controller using OMP.

Depending on the network topology, some routes might be advertised from multiple devices.

In a three tier model, access layer aggregation and FHRP is done at the distribution layer. Not core.

The core is all about speed and reliability/redundancy.

With the Cisco SD-WAN solution, network segmentation is accomplished via VPNs.

A is correct.

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/nx-os/vxlan/configuration/guide/b_NX-OS_VXLAN_Configuration_Guide/campus-fabric.pdf

"Fabric Edge Node : Fabric edge nodes are responsible for admitting, encapsulating/decapsulating and forwarding traffic to and from endpoints connected to the fabric edge"