How does the Cisco SD-Access control plane simplify traditional routing environments?

Routing adjacencies are still required in the underlay network to establish connectivity between fabric devices, typically using interior gateway protocols like IS-IS or OSPF.

Cisco SD-Access leverages Locator/ID Separation Protocol (LISP) to decouple the Endpoint Identifier (EID) from the Routing Locator (RLOC), meaning fabric devices only need to know RLOCs for forwarding. This separation significantly reduces the size and complexity of routing tables across the network.

Routers in SD-Access do not query *all* routes to the map server; instead, they query the map server for the RLOC of a *specific* EID when they need to forward traffic to an unknown endpoint.

SD-Access aims to simplify routing by *avoiding* the sharing of full routing tables; instead, it uses a map-and-encapsulate system (LISP) to dynamically resolve endpoint locations, preventing every router from needing full knowledge of all paths.