Review of the Exhibit:

The exhibit shows the switch configuration for Leaf-1 and Leaf-2. The configurations include route

distinguishers, VRF targets, and service IDs, all of which are crucial for ensuring proper operation in

an EVPN-VXLAN environment.

Service-ID Consistency:

The service ID must be consistent across all participating leaf devices in the same EVPN instance to

ensure that they are part of the same VXLAN overlay network.

VRF Target Consistency:

The vrf-target parameter must also be consistent across devices to ensure that VRFs (Virtual Routing

and Forwarding instances) are correctly imported and exported between leaf nodes.

Conclusion:

Option B: Correct—Setting the same service-id on Leaf-2 ensures that it is part of the same VXLAN

overlay as Leaf-1.

Option D: Correct—The vrf-target on Leaf-2 should match Leaf-1 to ensure consistent routing policies

and proper route exchange.

Understanding the Exhibit Setup:

The network diagram shows an EVPN-VXLAN setup, a common design for modern data centers

enabling Layer 2 and Layer 3 services over an IP fabric.

Leaf1 and Leaf2 are the leaf switches connected to Server1 and Server2, respectively, with each

server in a different subnet (172.16.1.0/24 and 172.16.2.0/24).

Spine1 and Spine2 are part of the IP fabric, interconnecting the leaf switches.

EVPN-VXLAN Basics:

EVPN (Ethernet VPN) provides Layer 2 and Layer 3 VPN services using MP-BGP.

VXLAN (Virtual Extensible LAN) encapsulates Layer 2 frames into Layer 3 packets for transmission

across an IP network.

VTEP (VXLAN Tunnel Endpoint) interfaces on leaf devices handle VXLAN encapsulation and

decapsulation.

Integrated Routing and Bridging (IRB):

IRB interfaces are required on leaf1 and leaf2 (where the endpoints are directly connected) to route

between different subnets (in this case, between 172.16.1.0/24 and 172.16.2.0/24).

The IRB interfaces provide the necessary L3 gateway functions for inter-subnet communication.

Traffic Flow Analysis:

Traffic from Server1 (172.16.1.1) destined for Server2 (172.16.2.1) must traverse from leaf1 to leaf2.

The traffic will be VXLAN encapsulated on leaf1, sent over the IP fabric, and decapsulated on leaf2.

Since the communication is between different subnets, the IRB interfaces on leaf1 and leaf2 are

crucial for routing the traffic correctly.

Correct Statements:

C . An IRB Interface must be configured on leaf1 and leaf2: This is necessary to perform the inter-

subnet routing for traffic between Server1 and Server2.

D . Traffic from server1 to server2 will transit the VXLAN tunnel between leaf1 and leaf2: This

describes the correct VXLAN operation where the traffic is encapsulated by leaf1 and decapsulated

by leaf2.

Data Center Reference:

In EVPN-VXLAN architectures, the leaf switches often handle both Layer 2 switching and Layer 3

routing via IRB interfaces. This allows for efficient routing within the data center fabric without the

need to involve the spine switches for every routing decision.

The described traffic flow aligns with standard EVPN-VXLAN designs, where direct VXLAN tunnels

between leaf switches enable seamless and scalable communication across a data center network.

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.

Understanding Pure IP Fabric:

A pure IP fabric is a network design where all devices operate at Layer 3, meaning that each device in

the fabric is a router that makes forwarding decisions based on IP addresses.

Layer 2 Support:

In a pure IP fabric, traditional Layer 2 protocols such as Spanning Tree Protocol (STP) or VLANs are not

supported. Instead, the network relies entirely on Layer 3 routing protocols to manage traffic

between devices.

Routing Functionality:

Since devices in an IP fabric operate as Layer 3 routers, they handle IP routing and provide network

services based on IP addresses, not on MAC addresses or Layer 2 switching.

Conclusion:

Option A: Correct—Devices in an IP fabric function as Layer 3 routers.

Option D: Correct—A pure IP fabric does not support traditional Layer 2 protocols, making it a purely

routed environment.

Zero-Touch Provisioning (ZTP):

ZTP is a feature that allows for the automatic provisioning of devices with minimal manual

intervention. It is widely used in large-scale deployments to quickly bring new devices online.

Key Requirements for ZTP:

A . DHCP Server: A DHCP server is crucial for ZTP as it provides the necessary information to new

devices, such as the IP address, the location of the software image, and configuration files.

D . File Server: The file server is where the software image and configuration files are stored. The

device downloads these files during the provisioning process.

Incorrect Options:

B . Syslog Server: While a syslog server is important for logging and monitoring, it is not a

requirement for the initial provisioning process.

C . NTP Server: An NTP server is used for time synchronization, which is essential for accurate logging

and operation but not specifically required for ZTP.

Data Center Reference:

ZTP simplifies the deployment process by automating the initial configuration steps, relying heavily

on DHCP for communication and a file server for delivering the necessary configuration and

software.