Which of the following is NOT how prefixes are typically learned and advertised in a...

Comprehensive and Detailed Explanation with Exact Extracts:

Options A, B, and C describe standard leaf-spine eBGP operation:

Leaf routers peer with spines (eBGP), advertising local prefixes (Option C).

Spines learn prefixes from leaves (Option B) and re-advertise them to other leaves (Option A).

Extract from Nokia Data Center Fabric Guide (Section: eBGP Leaf-Spine):

"Leaf routers establish eBGP sessions with spine routers, advertising prefixes of locally attached endpoints. Spine routers propagate these prefixes to all other leaf routers, providing full connectivity."

Option D is FALSE: Leaf routers do not peer directly with each other in standard designs. They communicate via spines.

Extract from Nokia Data Center Fabric Guide (Section: Routing Design):

"Leaf routers never establish direct eBGP sessions with other leaf routers. All inter-leaf communication occurs via spine routers, which act as route reflectors or forwarding hubs."