Understanding EVPN-VXLAN Architectures:

EVPN-VXLAN overlays allow for scalable Layer 2 and Layer 3 services in modern data centers.

CRB (Centralized Routing and Bridging): In this architecture, the Layer 3 routing is centralized on

spine devices, while the leaf devices focus on Layer 2 switching and VXLAN tunneling. This setup is

optimal when the goal is to centralize routing for ease of management and to avoid complex routing

at the leaf level.

ERB (Edge Routing and Bridging): This architecture places routing functions on the leaf devices,

making it a distributed model where each leaf handles routing for its connected hosts.

Architecture Choice for Spine Routing:

Given the requirement to ensure Layer 3 routing happens on the spine devices, the CRB (Centralized

Routing and Bridging) architecture is the correct choice. This configuration offloads routing tasks to

the spine, centralizing control and potentially simplifying the overall design.

Explanation:

With CRB, the spine devices perform all routing between VXLAN segments. Leaf switches handle

local switching and VXLAN encapsulation, but routing decisions are centralized at the spine level.

This model is particularly advantageous in scenarios where centralized management and routing

control are desired, reducing the complexity and configuration burden on the leaf switches.

Data Center Reference:

The CRB architecture is commonly used in data centers where centralized control and simplified

management are key design considerations. It allows the spines to act as the primary routing

engines, ensuring that routing is handled in a consistent and scalable manner across the fabric.