The Design workflow in Cisco DNA Center is used in a greenfield deployment where there is no existing infrastructure. It allows engineers to create the structure and framework of the network from scratch, including the physical topology, network settings, and device type profiles2.
The Design area is where you create the structure and framework of your network, including the physical topology, network settings, and device type profiles that you can apply to devices throughout your network.
Use the Design workflow if you do not already have an existing infrastructure. If you have an existing infrastructure, use the Discovery feature.
https://www.cisco.com/c/en/us/td/docs/cloud-systems-management/network-automation-and-management/dna-c Reference: https://synoptek.com/insights/it-blogs/greenfield-vs-brownfield-software-development/"Greenfield development refers to developing a system for a totally new environment and requires development from a clean slate - no legacy code around. It is an approach used when you're starting fresh and with no restrictions or dependencies."