A network administrator is evaluating the functions of underlay and overlay components within a Cisco Software-Defined Access (SD-Access) fabric deployment. Which two statements accurately describe the responsibilities and operational relationships of the underlay and overlay networks? (Select two.)
- The underlay network relies on traditional routing protocols, such as OSPF or IS-IS, to establish unicast IP reachability between physical fabric nodes.Cevap
- The overlay network utilizes Virtual Extensible LAN (VXLAN) encapsulation to transport virtualized Layer 2 and Layer 3 user traffic across the underlay infrastructure.Cevap
- CThe underlay network uses LISP to dynamically map virtual host endpoint identifiers (EIDs) to physical routing locators (RLOCs).
- DThe overlay network eliminates the requirement for physical IP routing between fabric edge nodes.
- EThe underlay network performs packet encapsulation by adding MAC-in-UDP headers to client frames at access ports.
Cevap
The correct statements are that the underlay network relies on traditional routing protocols (like OSPF or IS-IS) to establish IP reachability between physical fabric nodes, and the overlay network utilizes VXLAN encapsulation to transport Layer 2 and Layer 3 user traffic across the underlay infrastructure.
In software-defined fabric architectures (like Cisco SD-Access), the underlay provides basic physical connectivity and IP reachability using traditional IGPs (such as OSPF or IS-IS). The overlay runs on top of the underlay and uses VXLAN to encapsulate Layer 2 and Layer 3 frames into UDP packets, allowing virtual network separation independently of physical cabling.
Adım Adım Çözüm
Anahtar Kavram
Underlay vs. Overlay Architecture in SDN Fabrics