JN0-480 Data Center Specialist (JNCIS-DC) Questions and Answers

BGP is the protocol used to advertise EVPN routes. EVPN routes are a new type of BGP network layer reachability information (NLRI) that carry MAC address and IP prefix information for Ethernet VPNs. EVPN routes are exchanged between PEs using BGP multiprotocol extensions (MP-BGP) over MPLS, VXLAN, SR, or SRv6 tunnels. EVPN routes enable PEs to learn the reachability of MAC addresses and IP prefixes of different sites within the same EVPN instance. EVPN routes also support various features such as fast convergence, redundancy, aliasing, and inter-subnet routing. The other options are incorrect because:

• A. OSPF is wrong because OSPF is an interior gateway protocol (IGP) that is used to advertise IP routes within an autonomous system. OSPF is not used to advertise EVPN routes, which are a type of BGP NLRI that carry MAC address and IP prefix information for Ethernet VPNs.
• C. IS-IS is wrong because IS-IS is an interior gateway protocol (IGP) that is used to advertise IP routes and MPLS labels within an autonomous system. IS-IS is not used to advertise EVPN routes, which are a type of BGP NLRI that carry MAC address and IP prefix information for Ethernet VPNs.
• D. RIP is wrong because RIP is an interior gateway protocol (IGP) that is used to advertise IP routes within an autonomous system. RIP is not used to advertise EVPN routes, which are a type of BGP NLRI that carry MAC address and IP prefix information for Ethernet VPNs. References:
• EVPN Fundamentals
• RFC 9136 - IP Prefix Advertisement in Ethernet VPN (EVPN)
• EVPN Type-5 Routes: IP Prefix Advertisement
• Understanding EVPN Pure Type 5 Routes

 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

According to the Juniper documentation1, a generic system is a device that is not managed by Juniper Apstra and does not have a specific role or type assigned to it. A generic system can be used to represent a server, a firewall, a load balancer, or any other device that is not part of the fabric. In the exhibit, the device shown is a generic system, as indicated by its role, system type, and management level. Therefore, the correct answer is B. The device shown is a generic system.

According to the Juniper documentation2, a LAG is a link aggregation group that bundles multiple physical interfaces into a single logical interface. A LAG can provide increased bandwidth, redundancy, and load balancing for the network traffic. In the exhibit, the device shown has four physical interfaces that are part of a LAG, as indicated by their description and li_type. The LAG is facing the leaf pair, which are the two switches that connect to the device. Therefore, the correct answer is C. Four physical interfaces exist in a LAG facing the leaf pair. References: Generic Systems (Datacenter Design), Form LAG | Apstra 4.1 | Juniper Networks

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

A graph query is a component that identifies devices that supply data for a specific probe. A graph query is an expression that matches nodes in the Apstra graph database based on their attributes, such as device name, role, type, or tag. A graph query can be used to select the source devices for the input processors of a probe, as well as to filter the data by device attributes in the subsequent processors of a probe12. References:

• Probes
• Apstra IBA Getting Started Tutorial

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 specifies a connection between the interfaces of two devices, such as a leaf and a spine, a leaf and a server, or a leaf and an external gateway. An interface map can also specify port transformations, such as breaking out a 40 GbE port into four 10 GbE ports, or disabling unused ports. An interface map can be used to achieve the intended network configuration rendering and to enable features such as LAG, ESI-LAG, or MLAG. Therefore, the correct answer is B. An interface map specifies a connection between the interfaces of two devices. References: Interface Maps (Datacenter Design)

VXLAN VNIs are virtual network identifiers that are used to identify and isolate Layer 2 segments in the overlay network. VXLAN VNIs have the following characteristics:

• VNIs can have over 16 million unique values. This is because VXLAN VNIs are 24-bit fields that can range from 4096 to 16777214, according to the VXLAN standard1. This allows VXLAN to support a large number of Layer 2 segments and tenants in the network.
• VNIs identify a broadcast domain. This is because VXLAN VNIs are used to group the end hosts that belong to the same Layer 2 segment and can communicate with each other using VXLAN tunnels. The VXLAN tunnels are established using the VTEP information that is distributed by EVPN. The VTEPs are VXLAN tunnel endpoints that perform the VXLAN encapsulation and decapsulation. The VXLAN tunnels preserve the Layer 2 semantics and support the broadcast, unknown unicast, and multicast traffic within the same VNI2.

The following two statements are incorrect in this scenario:

• VNIs identify a collision domain. This is not true, because VXLAN VNIs do not identify a collision domain, which is a network segment where data packets can collide with each other. VXLAN VNIs identify a broadcast domain, which is a network segment where broadcast traffic can reach all the devices. Collision domains are not relevant in VXLAN networks, because VXLAN uses MAC-in-UDP encapsulation and IP routing to transport the Layer 2 frames over the Layer 3 network1.
• VNIs are alphanumeric values. This is not true, because VXLAN VNIs are numeric values, not alphanumeric values. VXLAN VNIs are 24-bit fields that can range from 4096 to 16777214, according to the VXLAN standard1. Alphanumeric values are values that contain both letters and numbers, such as ABC123 or 1A2B3C.

References:

• Virtual Extensible LAN (VXLAN) Overview
• EVPN LAGs in EVPN-VXLAN Reference Architectures

Intent-based analytics (IBA) is a feature of Juniper Apstra that allows you to combine intent from the network design with current and historic data from devices to reason about the network at-large1. IBA has the following characteristics:

• It is a real-time information processing pipeline. This means that IBA can ingest, process, and analyze large amounts of data from devices in real time, using agents and probes. Agents are software components that collect data from devices and send them to the Apstra server. Probes are user-defined queries that aggregate data across devices and generate advanced data that can be more easily reasoned about1.
• It is used to establish network performance baselines. This means that IBA can use the advanced data to measure and monitor the network performance against the expected outcomes and service levels. IBA can also use the historic data to create baselines that represent the normal behavior and state of the network2.
• It alerts the network operator when network performance moves away from the baseline. This means that IBA can detect and report any anomalies or deviations from the baseline or the intent in the network. IBA can also provide insights and recommendations for troubleshooting and resolving the issues2.

The following two statements are incorrect in this scenario:

• It indicates when device operating versions require updating. This is not true, because IBA does not provide any information or guidance about the device operating versions or updates. IBA is focused on the network performance and compliance, not on the device maintenance or upgrade1.
• It collects information from vendor websites. This is not true, because IBA does not collect any information from vendor websites or external sources. IBA only collects information from the devices in the network, using agents and probes1.

References:

• Intent-Based Analytics — Apstra 3.3.0 documentation
• What is Intent Based Networking? | Juniper Networks US

According to the Juniper documentation1, a configlet is a configuration template that augments Apstra’s reference design with non-native device configuration. They consist of one or more generators. Each generator specifies a NOS type (config style), when to render the configuration, and CLI commands (and file name as applicable). Some applications for configlets include the following:

• Syslog
• SNMP access policy
• TACACS / RADIUS
• Management ACLs
• Control plane policing
• NTP
• Username / password

Therefore, the correct answer is C and D. syslog configuration and NTP configuration. These are examples of non-native device configuration that can be added using a configlet. Static route configuration and policy configuration are not applicable in this scenario, because they are part of the reference design configuration that should not be replaced or modified by a configlet. References: Configlets (Datacenter Design), Configlet Examples (Design)

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

A connectivity template is a set of configuration parameters that can be applied to a device or a group of devices in a blueprint. A blueprint is a logical representation of the network design and intent. A primitive is a basic unit of configuration that can be added to a connectivity template. A primitive can be a link, a peering, a policy, or a service. In the exhibit, the red-striped primitives indicate that further configuration is required for them to be compatible with the connectivity template design. The red stripes mean that the primitive is incomplete or invalid, and it needs to be edited or deleted. For example, the IP Link primitive needs to have the interface name and IP address specified for each end of the link. The other options are incorrect because:

• A. The gray-solid primitives indicate further configuration is required is wrong because the gray-solid primitives indicate that they are compatible with the connectivity template design. The gray color means that the primitive is valid and complete, and it does not need any further configuration.
• B. The gray-solid primitives indicate that they are incompatible with the connectivity template design is wrong because the gray-solid primitives indicate that they are compatible with the connectivity template design, as explained above.
• C. The red-striped primitives indicate that they are incompatible with the connectivity template design is wrong because the red-striped primitives indicate that further configuration is required, not that they are incompatible. The red stripes mean that the primitive is incomplete or invalid, but it can be fixed by editing or deleting it. References:
• Connectivity Templates
• Data Center Automation Using Juniper Apstra
• Config Rendering in Juniper Apstra

In the case of IP Clos data center five-stage fabric design, the super spines are the devices that provide the highest level of aggregation in the network. They have two main roles:

• Super spines are used to interconnect two different data center pods. A pod is a cluster of leaf and spine devices that form a 3-stage Clos topology. A 5-stage Clos topology consists of multiple pods that are connected by the super spines. This allows for scaling the network to support more devices and bandwidth.
• Super spines connect to all spine devices within the five-stage architecture. The spine devices are the devices that provide the second level of aggregation in the network. They connect to the leaf devices, which are the devices that provide access to the end hosts. The super spines connect to all the spine devices in the network, regardless of which pod they belong to. This provides any-to-any connectivity between the pods and enables optimal routing and load balancing.

The following two statements are incorrect in this scenario:

• Super spines are used to connect leaf nodes within a data center pod. This is not true, because the leaf nodes are connected to the spine nodes within the samepod. The super spines do not connect to the leaf nodes directly, but only through the spine nodes.
• Super spines are always connected to an external data center gateway. This is not true, because the super spines are not necessarily involved in the external connectivity of the data center. The external data center gateway is a device that provides the connection to the outside network, such as the Internet or another data center. The external data center gateway can be connected to the super spines, the spine nodes, or the leaf nodes, depending on the design and the requirements of the network.

References:

• 5-stage Clos Architecture — Apstra 3.3.0 documentation
• 5-Stage Clos Architecture | Juniper Networks
• Extreme Fabric Automation Administration Guide

The Juniper Apstra Rendered configuration is the configuration that is generated from the staged blueprint and applied to the devices in the network. The Rendered configuration is dynamically rendered at commit time, which means that it is created on the fly based on the latest changes and validations in the blueprint. The Rendered configuration is not stored in any database, but it can be viewed in the Apstra UI or downloaded as a file. The Rendered configuration reflects the desired state of the network as defined by the intent of the blueprint. The other options are incorrect because:

• A. It is built at commit time and stored in a MySQL database is wrong because the Rendered configuration is not stored in any database, let alone a MySQLdatabase. Apstra uses a graph database to store the network topology and configuration data, not a relational database like MySQL.
• B. It is stored in a NoSQL database and incrementally updated is wrong because the Rendered configuration is not stored in any database, let alone a NoSQL database. Apstra uses a graph database to store the network topology and configuration data, not a non-relational database like NoSQL. The Rendered configuration is not incrementally updated, but dynamically rendered at commit time.
• D. It is rendered from the graph database and stored locally is wrong because the Rendered configuration is not rendered from the graph database, but from the staged blueprint. The graph database stores the network topology and configuration data, but the Rendered configuration is generated from the blueprint, which is a logical representation of the network design and intent. The Rendered configuration is not stored locally, but it can be downloaded as a file if needed. References:
• Config Rendering in Juniper Apstra
• AOS Device Configuration Lifecycle
• Configlets (Datacenter Design)

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

Juniper Apstra provides four system-defined user roles that are available in the Apstra GUI environment. They are: administrator, device_ztp, viewer, and user1. Based on the web search results, we can infer the following statements:

• viewer: This role includes permissions to only view various elements in the Apstra system, such as blueprints, devices, design, resources, external systems, platform, and others. Users with this role cannot create, edit, or delete any element12.
• user: This role includes permissions to view and edit various elements in the Apstra system, such as blueprints, devices, design, resources, external systems, platform, and others. Users with this role cannot create or delete any element12.
• authorized: This is not a system-defined user role in Juniper Apstra. It is a term used to describe users who have been authenticated by an external system, such as LDAP, Active Directory, TACACS+, or RADIUS3.
• root: This is not a system-defined user role in Juniper Apstra. It is a term used to describe the superuser account on a Linux system, which has full access to all commands and files. Creating a user in the Apstra GUI does not provide that user access to the Apstra platform via SSH. To access the Apstra platform via SSH, you must create a local Linux system user4. References:
• User / Role Management Introduction
• User/Role Management (Platform)
• AAA Providers
• User Profile Management

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 to acknowledge the device, which is a manual action that confirms the device identity and ownership. Acknowledging the device changes its status to Out of Service Ready (OOS-READY)12. References:

• Managing Devices
• AOS Device Configuration Lifecycle