JN0-480 Juniper Data Center Specialist (JNCIS-DC) Free Practice Exam Questions (2025 Updated)

To answer this question, we need to understand the concept of ESI values in EVPN LAGs. An ESI is a 10-byte value that identifies an Ethernet segment, which is a set of links that connect a multihomed device (such as a server) to one or more PE devices (such as leaf switches) in an EVPN network. The same ESI value must be configured on all the PE devices that connect to the same Ethernet segment. This allows the PE devices to form an EVPN LAG, which supports active-active or active-standby multihoming for the device. The ESI value can be manually configured (type 0) or automatically derived from LACP (type 1) or other methods. In the exhibit, Server A is connected to two leaf switches (QFX 5210) using a LAG with LACP enabled. Server B is connected to three leaf switches (QFX 5120) using a LAG with LACP enabled. Based on this information, the following statements are correct about ESI values for the server connections to the fabric:

C. A valid ESI value for Server A is 0x00.10.10.10.10.10.10.10.10.10. This is true because this ESI value can be automatically derived from the LACP configuration on the QFX 5210 devices. The LACP system ID is usually based on the MAC address of the device, and the LACP administrative key is a 2-byte value that identifies the LAG. For example, if the MAC address of the QFX 5210 device is 00:10:10:10:10:10 and the LAG ID is 10, then the LACP system ID is 00:10:10:10:10:10 and the LACP administrative key is 00:0A. The ESI value is then derived by concatenating the LACP system ID and the LACP administrative key, resulting in 00:10:10:10:10:10:00:0A. This ESI value can be represented in hexadecimal notation as 0x00.10.10.10.10.10.00.0A, or padded with zeros as 0x00.10.10.10.10.10.00.0A.00.00. This ESI value must be configured on both QFX 5210 devices that connect to Server A.

D. A valid ESI value for Server B is 0x00.00.00.00.00.00.00.00.00.00. This is true because this ESI value is a reserved value that indicates a single-homed device. Server B is connected to three leaf switches (QFX 5120) using a LAG, but it is not multihomed to any of them. This means that Server B does not need an ESI value to form an EVPN LAG with any of the leaf switches. Instead, Server B can use the reserved ESI value of 0x00.00.00.00.00.00.00.00.00.00, which indicates that it is a single-homed device and does not participate in any EVPN LAG. This ESI value must be configured on all three QFX 5120 devices that connect to Server B. Thefollowing statements are incorrect about ESI values for the server connections to the fabric:

A. A valid ESI value for Server A is 0x00.00.00.00.00.00.00.00.00.00. This is false because this ESI value is a reserved value that indicates a single-homed device. Server A is connected to two leaf switches (QFX 5210) using a LAG with LACP enabled, which means that it is multihomed to both of them. This means that Server A needs an ESI value to form an EVPN LAG with the leaf switches. The ESI value must be unique and non-zero for each Ethernet segment, so the reserved ESI value of 0x00.00.00.00.00.00.00.00.00.00 is not valid for Server A.

B. A valid ESI value for Server B is 0x00.20.20.20.20.20.20.20.20.20. This is false because this ESI value is not derived from the LACP configuration on the QFX 5120 devices. Server B is connected to three leaf switches (QFX 5120) using a LAG with LACP enabled, but it is not multihomed to any of them. This means that Server B does not need an ESI value to form an EVPN LAG with any of the leaf switches. Instead, Server B can use the reserved ESI value of 0x00.00.00.00.00.00.00.00.00.00, which indicates that it is a single-homed device and does not participate in any EVPN LAG. The ESI value of 0x00.20.20.20.20.20.20.20.20.20 is not valid for Server B, and it may cause conflicts with other Ethernet segments that use the same ESI value. References:

Ethernet Segment Identifiers, ESI Types, and LACP in EVPN LAGs

Understanding Automatically Generated ESIs in EVPN Networks

Ethernet Segment in EVPN: All You Need to Know

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. References:

Device Profiles

Juniper Device Profiles

 In Juniper Apstra, a widget is a graphical element that displays data from an intent-based analytics (IBA) probe. A widget can be used to monitor different aspects of the network and raise alerts to any anomalies. A widget can be viewed by itself or added to an analytics dashboard. A dashboard is a collection of widgets that can be customized and organized according to the user’s preference1.

The main dashboard in Juniper Apstra is the blueprint dashboard, which is the default view that shows the network information and configuration for the active blueprint. A blueprint is a logical representation of the network design and intent. The blueprint dashboard can display the system-generated dashboards, the user-generated dashboards, and the individual widgets that are relevant to the network2.

To make a widget appear on the main dashboard in Juniper Apstra, the user needs to set the Default toggle switch to On for the desired widget. This will add the widget to the blueprint dashboard, where it can be viewed along with other network information. The user can also remove the widget from the blueprint dashboard by setting the Default toggle switch to Off for the widget3. Therefore, the statement D is correct in this scenario.

The following three statements are incorrect in this scenario:

When creating the widget, select the Add to Blueprint Dashboard option. This is not true, because there is no such option when creating a widget in Juniper Apstra. The user can only select the widget type, the probe, and the display mode when creating a widget4. To add the widget to the blueprint dashboard, the user needs to set the Default toggle switch to On for the widget after creating it3.

On the blueprint dashboard, click on the Add Widget option. This is not true, because there is no such option on the blueprint dashboard in Juniper Apstra. The user can only view, edit, or delete the existing widgets and dashboards on the blueprint dashboard2. To add a widget to the blueprint dashboard, the user needs to set the Default toggle switch to On for the widget from the widgets table view3.

Widgets automatically appear on the blueprint dashboard. This is not true, because widgets do not automatically appear on the blueprint dashboard in Juniper Apstra. The user needs to manually add the widgets to the blueprint dashboard by setting the Default toggle switch to On for the widgets that they want to see on the blueprint dashboard3. The only exception is the widgets that are part of the system-generated dashboards, which are automatically created and added to the blueprint dashboard based on the state of the active blueprint2.

References:

Widgets Overview

Blueprint Summaries and Dashboard

Widgets Introduction

Create Widget

The cable map is a graphical representation of the physical connections between the devices in the data center fabric. It shows the status of the cables, interfaces, and BGP sessions for each device. You can use the cable map to identify and troubleshoot any cable, interface, or BGP anomalies that may occur in the fabric. You can also filter the cable map by device name, device type, device role, device state, cable state, interface state, or BGP state12. References:

Cable Map Overview

Cable Map User Guide

When working with logical devices, you specify where each port group is connected by selecting the port group layout and the port speed and role (s) for each port group. The Juniper Apstra UI offers two options to the operator for the port group role: unused and generic1.

Unused: This option means that the port group is not configured or used by Apstra. This can be useful for ports that are faulty, reserved, or not part of the data center fabric1.

Generic: This option means that the port group is configured with a generic role that is not specific to any device type or function. This can be useful for ports that are used for testing, troubleshooting, or custom purposes1. References:

Logical Devices

To configure a static route for traffic to exit a configured routing zone, you need to use the Connectivity Templates feature in the Juniper Apstra UI. A Connectivity Template is a set of configuration parameters that can be applied to a device or a group of devices in a blueprint. You can use Connectivity Templates to configure static routes, BGP, OSPF, and other network services. To create a Connectivity Template, you need to go to the Staged tab and select Connectivity Templates from the left menu. Then, you can click on the + icon to create a new template. You can specify the name, description, andscope of the template. The scope determines which devices or device groups the template will be applied to. You can also specify the order of the template, which determines the priority of the template when multiple templates are applied to the same device. After creating the template, you can add configuration items to the template. To add a static route, you need to select Static Route from the drop-down menu and enter the destination network, subnet mask, and next-hop IP address. You can also specify the administrative distance and the track object for the static route. After adding the configuration items, you need to save the template and commit the changes to the blueprint. The other options are incorrect because:

A. under Active -> Virtual -> Routing Zones is wrong because this option allows you to view and modify the existing routing zones, but not to configure static routes for them.

B. under Staged -> Virtual -> Routing Zones is wrong because this option allows you to create and delete routing zones, but not to configure static routes for them.

C. under Active -> Connectivity Templates is wrong because this option allows you to view the existing connectivity templates, but not to create or modify them. References:

Connectivity Templates

Data Center Automation Using Juniper Apstra

 Probes are the basic unit of abstraction in Intent-Based Analytics (IBA). They are used to collect, process, and analyze data from the network and raise anomalies based on specified conditions. Probes are composed of processors and stages that form a directed acyclic graph (DAG) of data flow. The following statements are correct about probes:

A. Default probes can be cloned, modified, and saved. This is true because Apstra provides a set of default probes that cover common use cases and scenarios. These probes can be cloned and modified to suit the specific needs of the user. The modified probes can be saved as new probes with different names and descriptions. This allows the user to customize and extend the functionality of the default probes.

D. Default probes are enabled, based on the intent for a blueprint. This is true because Apstra enables or disables the default probes automatically based on the intent of the blueprint. The intent of the blueprint is the high-level description of the desired state and behavior of the network. Apstra uses the intent to determine which default probes are relevant and applicable for the blueprint and enables them accordingly. For example, if the intent of the blueprint is to deployan EVPN-VXLAN fabric, Apstra will enable the default probes related to EVPN-VXLAN, such as EVPN-VXLAN Anomaly Detection, EVPN-VXLAN Fabric Health, and EVPN-VXLAN Fabric Validation. The following statements are incorrect about probes:

B. Only the variable parameters for default probes can be edited and saved. This is false because the user can edit and save any parameters for the default probes, not just the variable ones. The variable parameters are the ones that depend on the network topology, devices, or configuration, such as device names, interface names, IP addresses, VLAN IDs, etc. The user can also edit and save the fixed parameters, such as the duration, threshold, condition, etc. However, the user cannot edit and save the default probes directly. The user must clone the default probes first and then edit and save the cloned probes as new probes.

C. All default probes are enabled for all blueprints. This is false because Apstra does not enable all default probes for all blueprints. Apstra enables the default probes based on the intent of the blueprint, as explained above. This means that only the default probes that are relevant and applicable for the blueprint are enabled. For example, if the intent of the blueprint is to deploy a BGP IP fabric, Apstra will not enable the default probes related to EVPN-VXLAN, since they are not relevant for the blueprint. The user can also manually enable or disable the default probes as needed. References:

Probes

Create Probe

Intent-Based Analytics Overview

Device A serves as a spine in an IP fabric. An IP fabric is a network architecture that uses a spine-leaf topology to provide high performance, scalability, and reliability for data center networks. A spine-leaf topology consists of two layers of devices: spine devices and leaf devices. Spine devices are the core devices that interconnect all the leaf devices using equal-cost multipath (ECMP) routing. Leaf devices are the edge devices that connect to the servers, storage, or other network devices. In the exhibit, Device A is connected to four leaf devices using multiple links, which indicates that it is a spine device. The other options are incorrect because:

A. leaf is wrong because a leaf device is an edge device that connects to the servers, storage, or other network devices. In the exhibit, Device A is not connected to any servers, storage, or other network devices, but only to four leaf devices, which indicates that it is not a leaf device.

C. super spine is wrong because a super spine device is a higher-level device that interconnects multiple spine devices in a large-scale IP fabric. A super spine device is typically used when the number of leaf devices exceeds the port density of a single spine device. In the exhibit, Device A is not connected to any other spine devices, but only to four leaf devices, which indicates that it is not a super spine device.

D. server is wrong because a server device is a compute or storage device that connects to a leaf device in an IP fabric. A server device is typically the end host that provides or consumes data in the network. In the exhibit, Device A is not connected to any leaf devices, but only to four leaf devices, which indicates that it is not a server device. References:

IP Fabric Underlay Network Design and Implementation

IP Fabric Overview

IP Fabric Architecture

When an agent installation is successful, devices are placed into the Out of Service Quarantined (OOS-QUARANTINED) state using the Juniper Apstra UI. This state means that the device is not yet managed by Apstra and has not been assigned to any blueprint. The device configuration at this point is called Pristine Config. To make the device ready for use in a blueprint, you need toacknowledge the device, which changes its state to Out of Service Ready (OOS-READY)12. References:

Managing Devices

AOS Device Configuration Lifecycle

To create a new routing zone, you must specify the VRF Name, VLAN ID, and VNI for the routing zone. These are the mandatory fields in the user interface shown in the exhibit. The VRF Name is the name of the L3 domain that isolates the IP traffic of the routing zone from other routing zones. The VLAN ID is the identifier for the VLAN tagged Layer 3 links on external connections. The VNI is the VxLAN Network Identifier associated with the routing zone. The Routing Policies are optional fields that allow you to configure import and export route targets for the routing zone. These are onlyapplicable for EVPN routing zones, which use MP-EBGP as the overlay control protocol. The other options are incorrect because:

A. VRF Name only is wrong because you also need to specify the VLAN ID and VNI for the routing zone.

B. VRF Name and Routing policies is wrong because you also need to specify the VLAN ID and VNI for the routing zone. Routing policies are optional and only relevant for EVPN routing zones.

D. VRF Name, VLAN ID, VNI, Routing Policies is wrong because Routing Policies are optional and not required to create a new routing zone. References:

Routing Zones (Virtual)

Data Center Automation Using Juniper Apstra

According to the Juniper documentation1, EVPN route Type-3 is used to advertise the IP address of the VTEP and the VNIs that it supports. This allows the VTEPs to discover each other and form VXLAN tunnels for the VNIs that they have in common. EVPN route Type-2 is used to advertise the MAC and IP addresses of the hosts connected to the VTEPs. This allows the VTEPs to learn the MAC-to-IP bindings and the MAC-to-VTEP mappings for the hosts in the same VNI. Therefore, these two types of VXLAN tunnels will be automatically created by the EVPN control plane when using Juniper Apstra with the ERB design blueprint and two virtual networks in a common routing zone. References: Example: Configure an EVPN-VXLAN Centrally-Routed Bridging Fabric

A Juniper Apstra rack is a physical entity that contains one or more network devices, such as leaf nodes, access switches, or generic systems. A rack is used to organize and manage the network devices in the Apstra software application. A rack has the following characteristics:

It stores information on how leaf nodes connect to generic devices. This is because a rack can include generic systems, which are devices that are not managed by Juniper Apstra, but are connected to the network. A generic system can be a server, a firewall, a load balancer, or any other device that has a networkinterface. A rack stores the information on how the leaf nodes, which are the devices that provide access to the end hosts, connect to the generic devices, such as the port number, the link speed, the LAG mode, and the roles1.

It has a rack type, which defines the type and number of leaf devices, access switches, and/or generic systems that are used in the rack. A rack type is a resource that is created in the data center design phase, and it does not specify the vendor or the model of the devices. A rack type can be predefined or custom-made, and it can be used to create multiple racks with the same structure and configuration2.

It has a rack build, which assigns the specific vendor and model of the devices to the rack. A rack build is created in the staged phase, and it uses the rack type as a template. A rack build can also assign the resources, such as the IP addresses, the ASNs, and the VNIs, to the devices in the rack3.

It has a rack deployment, which applies the network configuration and services to the devices in the rack. A rack deployment is performed in the active phase, and it uses the rack build as a reference. A rack deployment can also monitor the network performance and compliance of the devices in the rack4.

The following three statements are incorrect in this scenario:

It stores information on how pods connect to super spines. This is not true, because a rack does not store any information on the pod or the super spine level of the network. A pod is a cluster of leaf and spine devices that form a 3-stage Clos topology, and a super spine is a device that connects multiple pods in a 5-stage Clos topology. A rack only stores information on the leaf and the access level of the network1.

It stores IP address and ASN pool information. This is not true, because a rack does not store any information on the IP address and ASN pools. IP address and ASN pools are resources that are created in the data center design phase, and they contain a range of IP addresses and ASNs that can be assigned to the devices and the virtual networks. A rack only uses the IP address and ASN pools to assign the resources to the devices in the rack build2.

It stores device port data rates and vendor information. This is not true, because a rack does not store any information on the device port data rates and vendor information. The device port data rates and vendor information are specified in the rack build, which assigns the specific vendor and model of the devices to the rack. A rack only uses the rack build to apply the network configuration and services to the devices in the rack deployment3.

References:

Racks (Staged)

Rack Types (Datacenter Design)

Rack Builds (Staged)

Racks (Active)

The leaf device in AS 65000 will receive three routes for the 10.100.0.0/16 prefix, one from each spine device in AS 65001, AS 65002, and AS 65003. Since ECMP load balancing is enabled, the leaf device will install all three routes in its routing table and distribute the traffic among them. The other options are incorrect because:

B. 1 is wrong because the leaf device will not receive only one route for the prefix. It will receive multiple routes from different spine devices and use ECMP to load balance among them.

C. 2 is wrong because the leaf device will not receive only two routes for the prefix. It will receive three routes from three spine devices, as explained above.

D. 4 is wrong because the leaf device will not receive four routes for the prefix. It will receive three routes from three spine devices, as explained above. The fourth spine device in AS 65004 is not directly connected to the leaf device and will not advertise the prefix to it. References:

IP Fabric Underlay Network Design and Implementation

BGP Multipath load sharing iBGP and eBGP

ECMP Load Balancing

According to the Juniper documentation1, an interface map is a configuration template that maps interfaces between logical devices and physical hardware devices (represented with device profiles) while adhering to vendor specifications. An interface map can be either predefined or custom. A predefined interface map is one that ships with Apstra software and supports most qualified Juniper devices. A custom interface map is one that is created by the user to meet specific requirements. An interface map can be stored in either the global catalog or the blueprint catalog. The global catalog contains all the interface maps that are available for use in any blueprint. The blueprint catalog contains the interface maps that are imported from the global catalog and used in a specific blueprint.

When a member of your organization makes changes to a predefined interface map, the following statements are correct:

Changes to interface maps in the global catalog do not affect interface maps that have already been imported into blueprint catalogs. This means that the existing blueprints that use the original version of the interface map will not be impacted by the changes. However, if you want to use the updated version of the interface map in a new or existing blueprint, you need to import it again from the global catalog.

Any changes made to predefined interface maps are discarded when Apstra is upgraded. This means that the changes will not be preserved across different versions of Apstra software. If you want to retain a customized interface map through Apstra upgrades, you need to clone the predefined interface map, give it a unique name, and customize it instead of changing the predefined one directly.

Therefore, the correct answer is A and B. Changes to interface maps in the global catalog do not affect interface maps that have already been imported into blueprint catalogs and any changes made to predefined interface maps are discarded when Apstra is upgraded. References: Edit Interface Map | Apstra 4.2 | Juniper Networks

To make the IP fabric a valid IP fabric, the connection between the two spine nodes must be removed. This is because an IP fabric is a network topology that uses a spine-leaf architecture, where the spine devices are only connected to the leaf devices, and the leaf devices are only connected to the spine devices. This creates a non-blocking, high-performance, and scalable network that supports Layer 3 routing protocols such as BGP or OSPF. The connection between the two spine nodes in the exhibit violates the spine-leaf design principle and introduces unnecessary complexity and potential loops in the network. The other options are incorrect because:

A. The IP fabric must consist of only one device model throughout the fabric is wrong because an IP fabric can support different device models as long as they are compatible and interoperable. The exhibit shows two different models of QFX switches, which are both supported by Juniper Networks for IP fabric deployments.

B. The connection between the two spine nodes must be increased to 40 Gbps is wrong because increasing the speed of the connection does not make the IP fabric valid. The connection between the two spine nodes should be removed, as explained above.

C. The IP fabric connections must be increased to a speed greater than 10 Gbps is wrong because the speed of the connections does not affect the validity of theIP fabric. The IP fabric can use any speed that meets the bandwidth and performance requirements of the network. 10 Gbps is a common speed for IP fabric connections, but higher or lower speeds can also be used depending on the network design and devices. References:

IP Fabric Underlay Network Design and Implementation

IP Fabric Overview

IP Fabric: Automated Network Assurance Platform

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 EBGPsessions 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.

References:

Exploring EVPN-VXLAN Overlay Architectures – Bridged Overlay

EVPN LAGs in EVPN-VXLAN Reference Architectures

EVPN-VXLAN Configuration Guide

When a new switch is added to Juniper Apstra software, it initially shows the “0 OS-Quarantined” status, which means that the device is not yet managed by Apstra and has not been assigned to any blueprint. The proper next step to make the device ready for use in a blueprint is to acknowledge the device, which is a manual action that confirms the device identity and ownership. Acknowledging the device changes its status to “OOS-Ready”, which means that the device is ready to be assigned to a blueprint and deployed12. References:

Managing Devices

AOS Device Configuration Lifecycle

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. References: 5-Stage Clos Architecture | Apstra 4.1 | Juniper Networks