Pass the Juniper JNCIS-MistAI JN0-460 Questions and answers with ExamsMirror

AMarvis Actions Missing VLANnotification indicates that anaccess pointis missing a VLAN configured on other APs within the same site.

Marvis identifies configuration inconsistencies by comparing VLAN assignments across devices.

The exhibit shows:

L2 gateways (blue dots)positioned at the distribution layer.

L3 gateways (red dots)positioned at thecore layer.

EVPN/VXLAN providing fabric connectivity between layers.

Access switches forwarding traffic into the fabric without acting as gateways.

This directly maps to thecentrally-routed bridging (CRB)model, where:

Bridging occurs at the access/distribution layer.

Routing (L3 gateway) occurs centrally at the core layer.

“In the core-distribution CRB model, Layer 2 gateways are deployed at the distribution switches, and Layer 3 gateways are deployed centrally at the core switches.”

Option A (ERB)is incorrect because ERB places the L3 gateway at the edge/access.

Option B (5-stage IP Clos)is incorrect — that topology has a leaf/spine architecture, not core/distribution.

Option C (3-stage IP Clos)is incorrect — that eliminates the distribution layer.

Option D (CRB)is correct, matching the diagram exactly.

Wired Assurance in Mist Cloud provides automated configuration for Juniper EX Series switches. The automation is built on open APIs and supports programmable workflows, which allow seamless integration with external systems and reduce manual configuration errors.

“Wired Assurance leverages 100% open APIs, enabling integration with third-party automation and orchestration tools. Combined with programmable workflows, this provides a consistent and scalable automation framework for switch deployment and management.”

Option A (100% open APIs): Correct — APIs enable automation and external integration.

Option C (programmable workflows): Correct — workflows automate repetitive tasks and provisioning.

Option B (client SLEs): Incorrect — this is part of user experience monitoring, not automation.

Option D (switch insights): Incorrect — this relates to telemetry and visibility, not automation.

Wired AssurancedefinesSLEs (Service Level Expectations)to provide measurable performance indicators for wired networks. These metrics identify root causes of network degradation by monitoring switch health, connection success, and throughput performance.

“Juniper Mist Wired Assurance delivers AI-driven insights across key wired SLEs including Successful Connects, Throughput, and Switch Health, giving visibility into user experience and switch performance.”

Option A (Capacity):Incorrect — capacity is used in wireless SLEs, not wired.

Option B (Successful Connects):Correct— tracks connection success rate and anomalies.

Option C (Switch Health):Correct— monitors hardware, software, and PoE status.

Option D (Coverage):Incorrect — pertains to wireless SLEs.

Option E (Throughput):Correct— measures data transfer rate, latency, jitter, and loss.

In acore-distribution campus fabricmodel, the EVPN-VXLAN overlay is establishedonly between the core and distribution tiers. Theaccess switches are not part of the EVPN fabric; they connect upstream to distribution but do not run VXLAN tunnels.

“In the core-distribution campus fabric, only the core and distribution layers participate in the EVPN-VXLAN topology. The access layer connects to the distribution switches and forwards traffic but does not take part in the EVPN-VXLAN fabric.”

Option A:Correct — EVPN-VXLAN is built between core and distribution tiers.

Option B:Incorrect — both coreand distributionparticipate, not just core.

Option C:Incorrect — access switches are excluded from EVPN-VXLAN participation.

Option D:Correct — the access layer does not participate in EVPN-VXLAN.

According to the Juniper Mist Wired Assurance Configuration Guide, the foundational step for implementing Layer 2 segmentation within the Mist UI is the creation of a "Network". In the context of Mist Wired Assurance, a Network is logically synonymous with a Virtual Local Area Network (VLAN). To define a network, a user must navigate to the Networks section—located within an organization-level template, a site-level configuration, or an individual switch configuration—and click to add a new entry.

The two mandatory parameters for this step are naming the VLAN and providing the corresponding VLAN ID. The name serves as a human-readable alias (such as "Corporate_Data" or "IoT_Devices") that allows administrators to easily reference the segment across different parts of the configuration without constantly tracking numeric IDs. The VLAN ID is the specific numeric value (ranging from 1 to 4094) that will be used by the switch for 802.1Q tagging on the physical wire.

This step is a prerequisite for more advanced configurations. Once a network is created with its name and ID, it can then be selected within a Port Profile. While creating a port profile (Option C) or an access policy (Option D) are common tasks in the deployment workflow, they are dependent on the prior existence of a defined Network. For instance, a Port Profile defines how a port behaves (e.g., access vs. trunk), but it must point to a specific Network name to know which VLAN to assign to that interface. Similarly, site variables can be used to override these VLAN IDs at specific locations, but the base definition requires the initial pairing of a name and a default ID in the portal.

According to Juniper Networks technical documentation regarding "Bridging and VLANs," Layer 2 network segmentation is primarily achieved through the implementation of Virtual Local Area Networks (VLANs). While VLANs provide critical segmentation services by grouping related devices into independent logical networks and containing broadcasts within specific domains, they are bound by the architectural constraints of the IEEE 802.1Q standard.

A fundamental limitation of this traditional Layer 2 approach is the address space of the VLAN identifier. The 802.1Q header allocates exactly 12 bits for the VLAN ID (VID). This mathematical constraint limits the total number of possible VLANs to 4,096 ($2^{12}$). Within the Junos operating system, VLAN IDs 0 and 4,095 are strictly reserved for system internal functions and cannot be assigned to user traffic, resulting in a maximum of 4,094 usable VLANs for network segmentation.

In modern enterprise environments—especially those involving large-scale multitenancy, cloud services, or high-density campus deployments—this 4,094 limit often becomes a significant bottleneck. Network administrators can exhaust this pool when attempting to provide granular isolation for thousands of unique device types, departments, and guest users. To overcome this specific limitation, Juniper recommends moving toward EVPN-VXLAN campus fabrics. VXLAN technology replaces the 12-bit VLAN tag with a 24-bit VXLAN Network Identifier (VNI), which theoretically supports over 16 million unique segments. This vast increase in scalability allows for the creation of administrative domains that far exceed the capabilities of traditional Layer 2 Ethernet bridging. While Layer 2 domains also face challenges related to Spanning Tree Protocol (STP) complexity and large broadcast diameters, the numeric exhaustion of the VLAN ID space remains the most definitive hardware-level limitation of standard Layer 2 segmentation.

Marvis is Juniper’s Virtual Network Assistant (VNA) that leverages AI to provide natural language queries, anomaly detection, and proactive troubleshooting across wireless, wired, and WAN networks.

“Marvis, the AI-driven Virtual Network Assistant, requires a Virtual Network Assistant subscription. The subscription enables Marvis to provide insights, recommendations, and natural language queries for Mist-managed networks.”

Option A (Access Assurance) is related to NAC/802.1X enforcement.

Option B (IoT Assurance) applies to profiling and securing IoT devices.

Option D (Wired Assurance) enables switch telemetry, onboarding, and assurance, but does not unlock Marvis.

Option C (Virtual Network Assistant) is correct — this subscription is required to enable Marvis AI.

In theCampus Fabric Deployment Wizard, the first step is defining thetopology type(3-stage or 5-stage IP Clos) and mapping thephysical connectionsbetween devices (core, distribution, and access).

“The first step in the campus fabric deployment process is to define the topology and identify physical connections between devices. This ensures correct port mapping between core, distribution, and access tiers.”

Option A:Correct— topology definition and physical connectivity mapping occur in the initial step.

Option B:Incorrect — the underlay network configuration happens after topology definition.

Option C:Incorrect — overlay configuration handles EVPN/VXLAN and routing setup, not physical cabling.

Option D:Incorrect — applying intent finalizes the deployment but does not define connectivity.

According to Juniper Mist documentation, the Throughput Service Level Expectation (SLE) is the primary metric used to measure the ability of wired clients to pass traffic across the physical network without impedance. This SLE is critical for diagnosing issues with real-time, high-bandwidth applications such as video streams, which are highly sensitive to packet loss and latency. Within the Throughput SLE, the Storm Control classifier is specifically designed to identify "bad user minutes" caused by the suppression of Broadcast, Unknown Unicast, and Multicast (BUM) traffic.

Storm control is a mechanism that enables the switch to monitor traffic levels and drop BUM packets when a specified traffic level—known as the storm control level—is exceeded. This prevents a "traffic storm" from proliferating and degrading the overall performance of the LAN. While this is a vital security feature to prevent network meltdowns, it can inadvertently impact legitimate traffic. For instance, if multicast-based video streams or other heavy BUM traffic exceed the configured bandwidth percentage on a port, the switch will drop those packets to protect the rest of the network.

When troubleshooting video stream issues, network administrators should inspect the Storm Control classifier to see if it is triggering "bad user minutes". If the Mist dashboard indicates failures under this classifier, it signifies that the switch hardware is actively dropping packets because the BUM traffic limit has been reached. This provides immediate root-cause evidence, allowing the administrator to determine if they need to adjust the storm control thresholds within the Port Profile or investigate the source of the excessive broadcast traffic. By correlating these hardware-level events with the end-user experience, Mist AI simplifies the resolution of complex performance problems that traditional "up/down" monitoring would miss.