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

 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

EVPN uses a route distinguisher (RD) value to identify which remote leaf device advertised the EVPN route. An RD is a 64-bit value that is prepended to the EVPN NLRI to create a unique VPNv4 or VPNv6 prefix. The RD value is usually derived from the IP address of the PE that originates the EVPN route. By comparing the RD values of different EVPN routes, a PE can determine which remote PE advertised the route and which VRF the route belongs to. The other options are incorrect because:

• B. a community tag is wrong because a community tag is an optional transitive BGP attribute that can be used to group destinations that share some common properties. A community tag does not identify the source of the EVPN route.
• C. a route target value is wrong because a route target (RT) value is an extended BGP community that is used to control the import and export of EVPN routes between VRFs. An RT value does not identify the source of the EVPN route.
• D. a VRF target value is wrong because there is no such thing as a VRF target value in EVPN. A VRF is a virtual routing and forwarding instance that isolates the IP traffic of different VPNs on a PE. A VRF does not have a target value associated with it. 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 the Juniper Apstra UI, the Resources menu allows you to create and manage global and local resources that are used for various elements of the network design and configuration. The Resources menu includes the following three types of resources that can be assigned to the network devices and virtual networks:

• ASN pools: These are pools of autonomous system numbers (ASNs) that are used for the underlay routing protocol (EBGP) between the leaf and spine devices. You can create ASN pools with either 2-byte or 4-byte ASNs, and assign them to the logical devices in the blueprint.
• VNI pools: These are pools of virtual network identifiers (VNIs) that are used for the overlay network (VXLAN) between the end hosts. You can create VNI pools with a range of VNIs, and assign them to the virtual networks in the blueprint.
• IP address pools: These are pools of IPv4 or IPv6 addresses that are used for various purposes in the network, such as the loopback addresses for the devices, the IP prefixes for the virtual networks, the host IP addresses for the end hosts, and the gateway IP addresses for the IRB interfaces. You can create IP address pools with a range of IP addresses, and assign them to the logical devices and virtual networks in the blueprint.

The following two types of resources are not assigned under the Resources menu:

• VTEP pools: These are not resources that can be created or assigned by the user. VTEPs are VXLAN tunnel endpoints that are automatically generated by the Apstra server based on the loopback IP addresses of the devices. VTEPs are used as the source and destination IP addresses for the VXLAN tunnels in the overlay network.
• Logical device pools: These are not resources that can be created or assigned by the user. Logical device pools are groups of logical devices that share the same role, interface map, and resource assignments in the blueprint. Logical device pools are used to simplify the network design and configuration by applying the same settings to multiple devices.

References:

• Resources Introduction
• ASN Pools (Resources)
• VNI Pools (Resources)
• IP Address Pools (Resources)

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)

 According to the Juniper documentation1, the Revert button is located on the Uncommitted tab of the blueprint page. The Uncommitted tab shows the changes that have been staged but not yet committed to the network. The Revert button allows you to discard any uncommitted changes and revert to the last committed state of the blueprint. This is useful if you want to cancel the changes that you have made or if you want to start over with a fresh slate. Therefore, the correct answer is B. The Revert button deletes any uncommitted changes within Apstra. References: Commit / Revert Changes to Blueprint | Apstra 4.2 | Juniper Networks

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, a routing zone is an L3 domain, the unit of tenancy in multi-tenant networks. You create routing zones for tenants to isolate their IP traffic from one another, thus enabling tenants to re-use IP subnets. In addition to being in its own VRF, each routing zone can be assigned its own DHCP relay server and external system connections. You can create one or more virtual networks within a routing zone, which means a tenant can stretch its L2 applications across multiple racks within its routing zone. For virtual networks with Layer 3 SVI, the SVI is associated with a Virtual Routing and Forwarding (VRF) instance for each routing zone isolating the virtual network SVI from other virtual network SVIs in other routing zones. If you’re using multiple routing zones, external system connections must be from leaf switches in the fabric. Routing between routing zones must be accomplished with external systems. Therefore, the correct answer is D. Use interconnection through an external gateway. References: Routing Zones

According to the Juniper documentation1, an ESI-LAG is a link aggregation group (LAG) that spans two or more devices and is identified by an Ethernet segment identifier (ESI). An ESI-LAG provides redundancy and load balancing for a multihomed server in an EVPN-VXLAN network. To configure an ESI-LAG, you need to ensure that the following requirements are met:

• The LACP system ID on both devices must be the same. This ensures that the LACP protocol can negotiate the LAG parameters and form a single logical interface for the server.
• The ESI ID on both devices must be the same. This ensures that the EVPN control plane can advertise the ESI-LAG as a single Ethernet segment and synchronize the MAC and IP addresses of the server across the devices.
• The VLAN ID and VNI on both devices must be the same. This ensures that the server can communicate with other hosts in the same virtual network and that the VXLAN encapsulation and decapsulation can work properly.

In the exhibit, the LACP system ID and the ESI ID on both devices are different, which prevents the ESI-LAG from coming up as multihomed. Therefore, the correct answer is B and D. The LACP system ID on both devices must be the same and the ESI ID on both devices must be the same. References: ESI-LAG Made Easier with EZ-LAG, Example: Configuring an ESI on a Logical Interface With EVPN-MPLS Multihoming, Introduction to EVPN LAG Multihoming

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 routing zone is an L3 domain, the unit of tenancy in multi-tenant networks. You create routing zones for tenants to isolate their IP traffic from one another, thus enabling tenants to re-use IP subnets. In addition to being in its own VRF, each routing zone can be assigned its own DHCP relay server and external system connections. You can create one or more virtual networks within a routing zone, which means a tenant can stretch its L2 applications across multiple racks within its routing zone. For virtual networks with Layer 3 SVI, the SVI is associated with a Virtual Routing and Forwarding (VRF) instance for each routing zone isolating the virtual network SVI from other virtual network SVIs in other routing zones. Therefore, the correct answer is D. A routing zone is used to enable the communication between two VNIs within a VRF. A routing zone is not used for L4-L7 inspection, securing routing protocols, or requiring firewalls. Those are not the purposes of a routing zone in Juniper Apstra software. References: Routing Zones

Time Voyager is a feature of Juniper Apstra that allows you to restore previous revisions of a blueprint, which is a logical representation of your network design and configuration. Time Voyager automatically saves the five most recent blueprint commits, which are the changes that you apply to the network. You can also manually save up to twenty-five revisions by keeping them, which prevents them from being overwritten by new commits. Therefore, the correct answer is B and D. Time Voyager retains the five most recent blueprint commits and Time Voyager retains up to twenty-five saved revisions. References: Time Voyager | Apstra 4.1 | Juniper Networks, Time Voyager Introduction | Apstra 4.2 | Juniper Networks, Juniper Apstra at a Glance | Flyer

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

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

According to the Juniper documentation1, the Resources menu in the Juniper Apstra UI allows you to create and manage various types of resources that are assigned to different elements of the network. Resources include the following types:

• IPv4 (including Host IPv4)
• IPv6 (including Host IPv6)
• ASN (autonomous system number)
• VNI (virtual network identifier)
• VLAN (virtual local area network)
• Integer (used for pool type VLAN in local pools in Freeform blueprints)

Therefore, the correct answer is C and D. ASN pools and IP pools are two types of resources that can be created in the Resources menu. Bridge domain identifier (BDI) and DHCP pools are not applicable in this scenario, because they are not part of the resources types supported by Juniper Apstra. References: Resources Introduction | Apstra 4.1 | Juniper Networks

The Links table in the Staged tab shows the physical connections between the devices in the fabric. It provides information such as the source and destination device names, hostnames, serial numbers, roles, interfaces, and link status. The Links table can be used to assist the team that is installing and cabling the devices by verifying that the devices are connected correctly and that the links are operational. The Links table can also be used to troubleshoot any connectivity issues that may arise during the installation process. For more information, see Links (Staged). References:

• Links (Staged)
• Topology (Staged)
• Staged

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