Juniper JN0-460 - JNCIS-MistAI-Wired

Juniper Mist automatically classifies ports to simplify visibility and automation withinWired Assurance. The Mist cloud analyzesport telemetryandlink behaviorto determine port roles, including uplinks.

“Mist uses machine learning and switch telemetry to automatically detect uplinks by analyzing traffic behavior and topology information. Uplink ports typically exhibit higher TX/RX utilization and are identified as spanning-tree root or forwarding ports connecting upstream devices.”

Option A:Correct — Mist examines traffic statistics. Ports with significantly higher TX/RX utilization relative to others are likely uplinks.

Option B:Incorrect — MTU size is not a classification criterion.

Option C:Correct — Mist usesSTP information(root or designated port status) to identify uplinks.

Option D:Incorrect — port description fields are for administrative purposes only and are not used by Mist analytics.

Abrownfield adoptionin Mist AI refers to onboarding existing Juniper switches (with existing configurations) into the Mist Cloud for management and monitoring. For the switch to connect successfully, it must be able to reach Mist Cloud services usingDNSandInternet connectivity.

“To onboard existing (brownfield) switches into Mist Cloud, the device must have outbound Internet connectivity and DNS resolution to discover Mist Cloud service endpoints.”

Option A:Correct— DNS is required for the switch to resolve Mist Cloud URLs.

Option B:Correct— Internet access is required for registration and telemetry exchange.

Option C:Incorrect — templates can be applied later but are not required for adoption.

Option D:Incorrect — Mist uses TCP ports 2200 or 443, not UDP 1280.

According to the Juniper Mist dashboard's firmware management interface shown in the exhibit, several key details of the switch upgrade process are visible. The "Upgrade switch firmware" dialog box is a standard component of Juniper Mist Wired Assurance used to manage Junos OS updates across the fabric.

The correct statement is that the switch will reboot after the upgrade. This is explicitly confirmed by the checkbox labeled "Reboot switch after image copy," which is currently selected in the exhibit. In Juniper's cloud-managed workflow, once the new software image is successfully transferred from the Mist cloud to the switch's local storage, the system requires a reboot to initialize the new Junos OS kernel and complete the installation process5. While some platforms support non-disruptive upgrades, the standard procedure for EX-series switches in a standalone or Virtual Chassis configuration typically involves a scheduled reboot to ensure the new version is correctly applied.

The other options are incorrect based on the visual evidence provided in the exhibit.

Option A: The exhibit clearly identifies the "Switch Model" as an EX2300-C-12P (the 'P' designating PoE support), not an EX2300-C-12T88.

Option C: The dialog box explicitly states "Total Switches selected to upgrade: 1," confirming this is a single-device operation rather than a bulk upgrade.

Option D: The "Upgrade to Version" field is set to 19.3R1.8, which indicates the target version, not the previous version10101010.

By providing these granular controls, Juniper Mist allows administrators to maintain strict version compliance across the site while choosing whether to immediately reboot or stage the image for a later maintenance window.

According toJuniper Mist Wired Assurance documentation, three built-in diagnostic tools available for testing switch functionality areBounce Port,Ping, andCable Test.

Bounce Portallows you to disable and re-enable a port to reset connectivity.

Pingverifies Layer 3 reachability between the switch and target IPs.

Cable Testperforms diagnostics to detect wiring faults, impedance mismatches, or cable lengths.

These tools are accessed directly from theSwitch Testing Toolssection in the Mist dashboard and are available for EX Series and QFX Series switches onboarded to the Mist cloud.

Group-Based Policy (GBP)is a Juniper EVPN-VXLAN feature that enablesmicrosegmentationwithout requiring multiple VRFs or VLANs. It is implemented within Juniper Mist’sWired Assurance and Campus Fabricframeworks.

“GBP provides scalable, identity-based segmentation for campus fabrics and is supported on EX4100 and EX4400 Series switches operating in EVPN-VXLAN mode under Mist management.”

The feature requires hardware and software support forEVPN-VXLAN and GBP tagging, which is currently available on specific EX models managed by Mist Cloud.

Option A:Correct— GBP requires compatible access switches, specifically EX4100 and EX4400 models.

Option B:Incorrect — GBP is centrally managed through Mist Cloud, not configured per switch.

Option C:Incorrect — GBP is provisioned via Mist Cloud, not the CLI.

Option D:Incorrect — GBP is not supported onallEVPN-capable switches; only on defined platforms (EX4100/EX4400).

According to Juniper documentation, a route distinguisher (RD) is a critical address qualifier used to ensure that network layer reachability information (NLRI) remains unique within a Multiprotocol BGP (MP-BGP) control plane, especially in multitenant environments. In a service provider network, different tenants may use identical, overlapping private IP address spaces (such as 192.168.1.0/24). If these routes were advertised without a qualifier, BGP—which typically only considers the IP prefix—would treat them as the same route and potentially overwrite one with the other based on standard BGP best-path selection.

The route distinguisher solves this by prepending an 8-byte field to the tenant's IP address, effectively transforming a 32-bit IPv4 prefix into a unique 96-bit VPN-IPv4 address. This 8-byte value is typically configured in formats such as as-number:number or ip-address:number. Because the resulting VPN-IPv4 prefix is unique to that specific routing instance, the service provider's BGP infrastructure can carry and distinguish between overlapping routes from multiple customers simultaneously.

It is important to differentiate the RD from a route target (RT). While the RD's sole purpose is to provide uniqueness so that routes are not discarded or overwritten, the route target is an extended community attribute used to control the import and export of these routes into the correct virtual routing and forwarding (VRF) tables on remote PE routers. In Juniper's Junos OS, each routing instance of type vrf or evpn must have a unique RD associated with it; failing to configure a unique RD or attempting to use the same RD across different instances will result in a configuration commit failure. This fundamental separation of "making routes unique" (RD) and "directing routes to the right place" (RT) allows for the scalable, isolated multitenancy required in modern EVPN-VXLAN campus and data center fabrics.

EVPN, when used with VXLAN, leveragesBGP MPLS/VXLAN control plane mechanisms. To prevent overlapping IP prefixes between different tenants or sites, EVPN uses aRoute Distinguisher (RD).

“In EVPN-VXLAN, the route distinguisher (RD) makes routes unique when overlapping IP prefixes or MAC addresses are advertised between multiple tenants or sites.”

Option A(designated forwarder) applies to multi-homing in EVPN, not prefix uniqueness.

Option B(Layer 2 gateway) does not prevent IP overlap; it bridges VLANs.

Option D(ESI) is used for identifying multi-homed Ethernet segments, not to differentiate overlapping subnets.

Option C(Route Distinguisher) is correct, as it uniquely identifies routes even if the IP addresses are the same across sites.

Mistwebhooksprovide real-time integration with external systems by streamingalertsandSLE (client) metrics.

They allow automation tools to react immediately to network health or performance changes.

According to Juniper Networks' validated designs for campus fabrics, the campus fabric core-distribution with edge-routed bridging (ERB) is the optimal architecture when high volumes of east-west traffic are present and access switches are restricted to Layer 2 operations. In an ERB design, the EVPN-VXLAN fabric extends from the core switches to the distribution switches.1 The critical differentiator is the placement of the default gateways (Integrated Routing and Bridging or IRB interfaces). In the ERB model, these gateways are moved from the core to the distribution layer, which effectively acts as the "edge" of the EVPN fabric.

By placing the Layer 3 gateways at the distribution layer, inter-VLAN (east-west) traffic is routed closer to the endpoints.2 This prevents the "hairpinning" effect found in Centrally-Routed Bridging (CRB) architectures, where traffic must travel all the way to the core layer to be routed between subnets before returning down to the distribution and access layers. This reduction in latency and core-link utilization is essential for modern campus environments with high server-to-server or client-to-client traffic patterns.

Furthermore, this architecture specifically accommodates Layer 2 access switches. In the ERB core-distribution model, the access switches are not part of the EVPN-VXLAN overlay; instead, they connect to the distribution tier using standard Link Aggregation Control Protocol (LACP) or ESI-LAG. This allows organizations to leverage existing legacy or lower-tier access switches that do not support advanced VXLAN capabilities while still benefiting from a robust, scalable EVPN-VXLAN fabric at the distribution and core layers.5 In contrast, while the campus fabric IP Clos also excels at handling east-west traffic, it requires the access switches themselves to perform VXLAN encapsulation/decapsulation (acting as VTEPs), which contradicts the requirement for access switches to operate only at Layer 2.

Dynamic Port Configuration (DPC)in Juniper Mist enablesautomatic switch port configurationbased on connected device type (e.g., phones, access points, printers). When setting up DPC, administrators define thematching criteria(such as MAC OUI or LLDP system name) and associate aConfiguration Profilethat determines which settings are applied.

“To configure Dynamic Port Configuration, you must assign the ports where DPC will run and select the configuration profile that defines how the port will be automatically configured when a matching device is detected.”

Option A:Correct— you must select the configuration profile to apply once the device type matches.

Option B:Incorrect — DPC does not use polling; it reacts to real-time LLDP/device discovery.

Option C:Correct— you must assign the ports on which DPC operates.

Option D:Incorrect — DPC is supported across EX models running compatible firmware but does not require manually setting a Junos version in configuration.