Most Recent Juniper JN0-480 Exam Questions & Answers

A pristine configuration in Juniper Apstra is the configuration file that is used to onboard a device into the Apstra software application.A pristine configuration contains the minimum settings that are required for the device to communicate with the Apstra server, such as the hostname, management IP address, username, password, and SSH key1. A pristine configuration has the following characteristics:

It is the configuration file placed on the device when decommissioning the device. This is because when a device is decommissioned from the Apstra software application, it is reverted back to its pristine configuration, which removes all the network configuration and services that were applied by the Apstra software application.This allows the device to be reused or repurposed for another network2.

It is the configuration file on a device before acknowledgment in Apstra. This is because when a device is onboarded into the Apstra software application, it is initially in the discovery state, which means that the device is discovered by the Apstra server, but not yet acknowledged by the user. In the discovery state, the device has the pristine configuration, which can be viewed and edited by the user.Once the user acknowledges the device, the device moves to the deployed state, which means that the device is ready to receive the network configuration and services from the Apstra software application3.

The following two statements are incorrect in this scenario:

It is the device's currently active configuration. This is not true, because the pristine configuration is not the device's currently active configuration, unless the device is in the discovery state or the decommissioned state.In the deployed state, the device's currently active configuration is the network configuration and services that are applied by the Apstra software application, which are based on the blueprint and the intent3.

It is the device's previously active configuration. This is not true, because the pristine configuration is not the device's previously active configuration, unless the device is in the decommissioned state. In the discovery state, the pristine configuration is the device's initial configuration, which may or may not be the same as the device's previous configuration before being onboarded into the Apstra software application.In the deployed state, the device's previously active configuration is the network configuration and services that were applied by the Apstra software application before the last commit3.

Pristine Config

Decommission Device

Device States

In the EVPN-VXLAN data center fabric bridged overlay architecture shown in the exhibit, the servers are connected to Leaf1 and Leaf6 using the same virtual network identifier (VNI). This means that the servers belong to the same Layer 2 domain and can communicate with each other using VXLAN tunnels across the fabric. The underlay network provides the IP connectivity between the leaf and spine devices, and it uses EBGP as the routing protocol. Therefore, the following two statements are correct in this scenario:

Loopback IPv4 addresses must be advertised into the EBGP underlay from leaf and spine devices. This is because the loopback addresses are used as the source and destination IP addresses for the VXLAN tunnels, and they must be reachable by all the devices in the fabric. The loopback addresses are also used as the router IDs and the BGP peer addresses for the EBGP sessions.

The underlay EBGP peering's must be established between leaf and spine devices. This is because the EBGP sessions are used to exchange the underlay routing information and the EVPN routes for the overlay network. The EBGP sessions are established using the loopback addresses of the devices, and they follow a spine-and-leaf topology, where each leaf device peers with all the spine devices, and each spine device peers with all the leaf devices.

The following two statements are incorrect in this scenario:

The underlay must use IRB interfaces. This is not true, because the underlay network does not provide any Layer 3 gateway functionality for the overlay network. The IRB interfaces are used to provide inter-VXLAN routing within the fabric, which is not the case in the bridged overlay architecture. The IRB interfaces are used in the edge-routed bridging (ERB) or the centrally-routed bridging (CRB) architectures, which are different from the bridged overlay architecture.

The underlay must be provisioned with PIMv2. This is not true, because the underlay network does not use multicast for the VXLAN tunnels. The VXLAN tunnels are established using EVPN, which uses BGP to distribute the MAC and IP addresses of the end hosts and the VTEP information of the devices. EVPN eliminates the need for multicast in the underlay network, and it provides optimal forwarding and fast convergence for the overlay network.

Exploring EVPN-VXLAN Overlay Architectures -- Bridged Overlay

EVPN LAGs in EVPN-VXLAN Reference Architectures

EVPN-VXLAN Configuration Guide

Referring to the exhibit, the image shows a simplified diagram of an IP fabric network connecting two servers, labeled as Server A and Server B. The IP fabric is a network architecture that uses a Clos topology to provide high bandwidth, low latency, and scalability for data center networks.The IP fabric consists of spine and leaf devices that use BGP as the routing protocol and VXLAN as the overlay technology1.

A broadcast domain is a logical portion of a network where any device can directly transmit broadcast frames to other devices at the data link layer (OSI Layer 2). A broadcast frame is a frame that has a destination MAC address of all ones (FF:FF:FF:FF:FF:FF), which means that it is intended for all devices in the same broadcast domain.A broadcast domain is usually bounded by a router, which does not forward broadcast frames to other networks2.

In the exhibit, there are two broadcast domains that an Ethernet frame will pass through when traversing the IP fabric from Server A to Server B. The first broadcast domain is the one that contains Server A and the leaf device that it is connected to. The second broadcast domain is the one that contains Server B and the leaf device that it is connected to. The IP fabric itself is not a broadcast domain, because it uses IP routing and VXLAN encapsulation to transport the Ethernet frames over the Layer 3 network. Therefore, the statement C is correct in this scenario.

The following three statements are incorrect in this scenario:

A) 1. This is not true, because there are not one, but two broadcast domains that an Ethernet frame will pass through when traversing the IP fabric from Server A to Server B. The IP fabric itself is not a broadcast domain, because it uses IP routing and VXLAN encapsulation to transport the Ethernet frames over the Layer 3 network.

B) 4. This is not true, because there are not four, but two broadcast domains that an Ethernet frame will pass through when traversing the IP fabric from Server A to Server B. The spine devices and the leaf devices that are not connected to the servers are not part of the broadcast domains, because they use IP routing and VXLAN encapsulation to transport the Ethernet frames over the Layer 3 network.

D) 3. This is not true, because there are not three, but two broadcast domains that an Ethernet frame will pass through when traversing the IP fabric from Server A to Server B. The IP fabric itself is not a broadcast domain, because it uses IP routing and VXLAN encapsulation to transport the Ethernet frames over the Layer 3 network.

IP Fabric Overview

Broadcast Domain - NetworkLessons.com

Device profiles are objects that associate a specific vendor model to a logical device in Juniper Apstra. Device profiles contain extensive hardware model details, such as form factor, ASIC, CPU, RAM, ECMP limit, and supported features. Device profiles also define how configuration is generated, how telemetry commands are rendered, and how configuration is deployed on a device.Device profiles enable the Apstra system to render and deploy the configuration according to the Apstra Reference Design12.Reference:

Device Profiles

Juniper Device Profiles

According to the Juniper documentation1, a five-stage Clos architecture allows for large-scale topologies with an additional aggregation layer that interconnects multiple pods into a single fabric. A pod is a group of racks that share the same spine devices. A rack is a group of leaf devices that connect to the same servers. To create a five-stage Clos network using Juniper Apstra, you need to choose the pod-based fabric type in the template creation wizard. This will allow you to specify the number of pods, planes, spines, and leaves for your network design. Therefore, the correct answer is D. pod-based.Reference:5-Stage Clos Architecture | Apstra 4.1 | Juniper Networks