Practice Free JN0-480 Data Center Specialist (JNCIS-DC) Exam Questions Answers With Explanation

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

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

The deploy phase is the final step in the Juniper Apstra data center fabric design and deployment process. In this phase, you apply the Apstra-rendered configuration to the devices and verify the intent of the blueprint. Based on the web search results, we can infer the following actions are required during the deploy phase12:

• Assign device profiles to the blueprint. This action associates a specific vendor model to each logical device in the blueprint. 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 Design34.
• Assign resources to the blueprint. This action allocates the physical devices, IP addresses, VLANs, and ASNs to the logical devices, networks, and routing zones in the blueprint. Resources can be assigned manually or automatically by the Apstra system. Assigning resources ensures that the blueprint has all the necessary elements to generate the configuration and deploy the fabric5 .
• Assign user roles to the blueprint. This action is not required during the deploy phase. User roles are defined at the system level, not at the blueprint level. User roles determine the permissions and access levels of different users in the Apstra system. User roles can be system-defined or custom-defined .
• Assign interface maps to the blueprint. This action is not required during the deploy phase. Interface maps are defined at the design phase, not at the deploy phase. Interface maps are objects that map the logical interfaces of a logical device to the physical interfaces of a device profile. Interface maps enable the Apstra system to generate the correct interface configuration for each device in the fabric . References:
• Deploy
• Deploy Device
• Device Profiles
• Juniper Device Profiles
• Resources

A configlet is a small piece of configuration that can be applied to a device or a group of devices to make persistent changes that are not overwritten by Apstra. Configlets can be used to install manual changes that are not part of the Apstra rendered configuration, such as custom commands, scripts, or features. Configlets can be created, edited, and deleted from the Apstra GUI or CLI12. References:

• Configlets Overview
• Configlets User Guide

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

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)

In the Juniper Apstra UI, you can create VNI pools for virtual networks that use VXLAN encapsulation in the overlay network. A VNI pool is a resource pool that contains a range of VNIs that can be assigned to the virtual networks. The valid VNI range for a VNI pool is 4096 through 16777214, according to the VXLAN standard1. Therefore, the statement B is correct in this scenario.

The following three statements are incorrect in this scenario:

• Any range is acceptable for the VNI pool. This is not true, because the VNI range has a lower and upper limit defined by the VXLAN standard1. The lower limit is 4096, and the upper limit is 16777214. Any VNI outside this range is invalid and cannot be used for VXLAN encapsulation.
• The valid VNI range is 2 through 4096. This is not true, because the VNI range does not start from 2, but from 4096. The VNIs from 2 to 4095 are reserved and cannot be used for VXLAN encapsulation1.
• The valid VNI range is 1 through 10000. This is not true, because the VNI range does not include 1, which is also reserved and cannot be used for VXLAN encapsulation1. The VNI range also does not end at 10000, but at 16777214, which is the maximum possible value for a 24-bit VNI field1.

References:

• VNI Pools (Resources)

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.

References:

• IP Fabric Overview
• Broadcast Domain - NetworkLessons.com

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)

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

The cabling 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 cabling map to verify and repair the cabling before deploying your blueprint. Based on the web search results, we can infer the following statements:

• Apstra can use LLDP data from the spine-to-leaf fabric devices to update the connections in the cabling map. This is true because Apstra can collect LLDP data from the devices using the Generic Graph Collector processor and use it to update the cabling map automatically. LLDP is a protocol that allows devices to exchange information about their identity, capabilities, and neighbors12.
• Apstra can use LLDP data from the leaf devices to update the leaf-to-generic connections in the cabling map. This is true because Apstra can also collect LLDP data from the leaf devices and use it to update the connections to the generic devices, such as routers, firewalls, or servers. Generic devices are devices that are not managed by Apstra but are part of the data center fabric23.
• You must manually change the cabling map to update spine-to-leaf fabric links. This is false because Apstra can use LLDP data to update the spine-to-leaf fabric links automatically, as explained above. However, you can also manually change the cabling map to override the Apstra-generated cabling, if needed24.
• You must manually change the cabling map to update leaf-to-generic links. This is false because Apstra can use LLDP data to update the leaf-to-generic links automatically, as explained above. However, you can also manually change the cabling map to override the Apstra-generated cabling, if needed24. References:
• LLDP Overview
• Edit Cabling Map (Datacenter)
• Generic Devices
• Import / Export Cabling Map (Datacenter)

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)

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

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