JN0-460 JNCIS-MistAI-Wired Questions and Answers

According to Juniper Mist documentation, the term "Adopting a Switch" specifically refers to the process of bringing an existing, already-configured switch—often termed a brownfield device—under the management of the Juniper Mist cloud. This is distinct from the "claiming" process, which is reserved for greenfield environments where new, factory-default switches are added using a QR code or activation code.

In a brownfield scenario, the switch is typically already in production or has a pre-existing local configuration that must be preserved or integrated into the Mist AI-driven dashboard. To adopt such a switch, the administrator must manually interact with the switch's Command Line Interface (CLI). The Mist portal provides a unique adoption command—a string of Junos OS configuration—that includes the specific URL for the Mist cloud and the organization’s unique registration token. Once this command is pasted into the switch's CLI and committed, the switch initiates an outbound connection to the Mist cloud via TCP port 2200 or 443.

Upon successful connection, the switch's status changes from "Unassigned" to "Connected" in the Mist dashboard. This transition allows the Mist AI engine to begin collecting telemetry, monitoring Service Level Expectations (SLEs), and performing automated troubleshooting. While the adoption process allows for "monitoring only" mode to avoid disrupting existing services, it is the fundamental first step for transitioning legacy Juniper infrastructure into a modern, cloud-managed Wired Assurance environment. This workflow is essential for organizations looking to leverage Marvis AI and automated operations without having to factory-reset their entire existing network.

RadSec(RADIUS over TLS) enhances traditional RADIUS authentication security by encapsulating RADIUS messages withinTCP and TLSinstead of UDP.

This ensures encrypted, reliable, and authenticated transmission between network devices (such as Juniper EX switches) and RADIUS servers.

It is often used in modernMist-managed wired networksto securely integrate withAccess Assuranceor external authentication systems.

According to Juniper Mist documentation regarding campus fabric design, the campus fabric IP Clos (also known as a 5-stage Clos) is the architecture that extends the EVPN-VXLAN protocol stack from the core tier down through the distribution tier and finally to the access tier. In this model, every switch in the hierarchy—from the high-capacity core switches to the wiring closet access switches—participates in the EVPN control plane and VXLAN data plane.

By extending EVPN-VXLAN to the access tier, the IP Clos architecture provides a standards-based, scalable framework that allows for seamless Layer 2 connectivity over a Layer 3 underlay across the entire campus333333333. This enables advanced features like Microsegmentation using Group-Based Policies (GBP) and Macrosegmentation via Virtual Routing and Forwarding (VRF) instances directly at the edge of the network.

In contrast, other architectures like "core-distribution" (either CRB or ERB) typically limit the EVPN-VXLAN fabric to the core and distribution layers, leaving the access tier to connect via traditional methods like LAG, Virtual Chassis, or standard Layer 2 trunks5555. The IP Clos architecture is specifically designed for large-scale deployments where high density, vendor interoperability, and end-to-end policy enforcement are critical6. By utilizing a 5-stage IP Clos, organizations can eliminate the complexities of Spanning Tree Protocol (STP) while maintaining a flexible, "any-to-any" communication path throughout the physical infrastructure.

According to Juniper Mist documentation, the Throughput Service Level Expectation (SLE) is the primary metric used to represent the ability of wired users to pass traffic across the network without impedance. This SLE provides a comprehensive oversight of network performance by identifying issues that degrade the user experience, such as storm control events, interface anomalies, and specifically uplink congestion.

Within the Throughput SLE, the Congestion classifier (also referred to as Congestion Uplink) is specifically designed to monitor for buffer saturation and packet drops (TxDrops). When traffic arriving at an interface exceeds its processing or forwarding capacity, packets are queued in a buffer; if this buffer becomes full, the switch begins dropping packets. Juniper Mist utilizes a specific formula considering the ratios of TxDrops to TxPackets, Transmitted bps to Link Speed, and Received Speed to Link Speed to determine if a "Bad User Minute" has occurred due to congestion.

A critical feature of Wired Assurance is the automatic identification of uplink interfaces. Mist identifies these high-capacity ports by analyzing switch telemetry for characteristics such as having a switch or router as an LLDP neighbor, being designated as a Spanning Tree Protocol (STP) root port, or exhibiting significantly higher packet counts compared to access ports. When congestion is detected on an interface identified as an uplink, the system recognizes that this bottleneck impacts every user on that switch. By correlating these drops with the Throughput SLE, network administrators can proactively identify when a site requires more bandwidth or a different fabric architecture to handle current traffic demands, rather than simply monitoring if the link is physically "up" or "down".

Comprehensive and Detailed Explanation From Exact Extract:

InEVPN-VXLANarchitectures, theVXLAN Tunnel Endpoint (VTEP)is the logical interface responsible for encapsulating and de-encapsulating Layer 2 Ethernet frames into VXLAN packets.

Each participating switch — typically the access or distribution node — hosts aVTEPthat maps local VLANs to VXLAN Network Identifiers (VNIs).

When a packet leaves a local VLAN, the VTEP encapsulates it in a VXLAN header and routes it through the underlay IP fabric.

When received at the destination VTEP, the frame is de-encapsulated and delivered to the appropriate local VLAN.

“VTEPs in an EVPN-VXLAN campus fabric perform MAC-to-VNI mapping and encapsulate/decapsulate traffic between virtualized network segments, allowing seamless Layer 2 and Layer 3 connectivity across an IP underlay.”

In Juniper Mist Cloud, administrative roles define what actions a user can perform within an organization. The ability to claim and onboard switches is granted to roles that have configuration or deployment privileges.

“Only users with Super User, Network Admin, or Installer roles can claim, onboard, or delete devices such as access points, switches, or gateways within a Mist organization.”

Option A (Network Admin):Correct— can claim and manage network devices.

Option B (Installer):Correct— role specifically intended for device onboarding and site setup.

Option C (Super User):Correct— full administrative privileges including device claiming.

Option D (Observer):Incorrect — view-only access.

Option E (Helpdesk):Incorrect — limited to troubleshooting functions, not device management.

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.

Juniper Wired Assurance licensingis based on switch port count and supports a range of hardware platforms. Subscriptions are available for12-port,24-port, and48-portmodels across the EX Series portfolio.

“Wired Assurance subscriptions are available for all supported EX Series switches in 12-port, 24-port, and 48-port license options, aligning to switch hardware configurations.”

Option A:Incorrect — 24-port only does not cover all options.

Option B:Incorrect — 12- and 24-port licenses exist, but 48-port is also supported.

Option C:Correct— Mist supports12-, 24-, and 48-portsubscription tiers.

Option D:Incorrect — 12-port alone is incomplete.

VXLAN (Virtual Extensible LAN) uses an overlay encapsulation method to carry Layer-2 frames over an IP underlay. This functionality is part of the data plane, which is responsible for packet forwarding and encapsulation/decapsulation.

“In an EVPN-VXLAN fabric, the control plane (via BGP EVPN) learns and advertises MAC and IP information, while the data plane encapsulates and forwards traffic using VXLAN tunnels between VTEPs.”

Option A is incorrect: IP learning happens in the control plane, not the data plane.

Option B is incorrect: MAC advertisement is done in the control plane through EVPN route types.

Option D is incorrect: MAC learning is handled by EVPN control plane, not the VXLAN data plane.

Option C is correct: the VXLAN data plane encapsulates the traffic in UDP tunnels between VTEPs.

In Juniper Mist,Greenfield adoptionapplies to new, cloud-ready switches (such as EX4100, EX4400, and QFX series) using aclaim or activation codeto securely connect to the Mist cloud.

Brownfield adoption, however, supports switches already deployed or not factory-fresh. These are manually onboarded by configuring outbound management connectivity and adopting them through the Mist portal.

This distinction enables both new and legacy EX/QFX environments to be cloud-managed under Wired Assurance.

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.

In anEVPN-VXLANarchitecture, theVXLAN Tunnel Endpoint (VTEP)is responsible for encapsulating and de-encapsulating Layer 2 Ethernet frames into VXLAN packets that traverse the IP underlay.

“Each device participating in a VXLAN overlay operates as a VXLAN Tunnel Endpoint (VTEP). The VTEP encapsulates Ethernet frames into VXLAN headers for transmission and de-encapsulates VXLAN packets back into Ethernet frames upon receipt.”

Option A:Incorrect — VLAN is a Layer 2 construct, not responsible for encapsulation.

Option B:Correct— VTEP handles VXLAN encapsulation and de-encapsulation.

Option C:Incorrect — root bridge pertains to STP, not VXLAN.

Option D:Incorrect — WXLAN policy is not a valid networking term in Juniper documentation.

Link Layer Discovery Protocol (LLDP)is a Layer 2 discovery protocol that allows network devices to advertise identity and capabilities to directly connected neighbors. While LLDP is useful for basic topology discovery, it has two key limitations inWired Assurance client identification:

“LLDP operates at Layer 2 between directly connected devices and must be explicitly enabled on all participating network elements to provide neighbor information. It cannot discover devices beyond the first physical hop.”

Option A:Correct— LLDP must beconfigured and enabledon each network device to function.

Option B:Incorrect — LLDP itself is scalable but limited to direct adjacency.

Option C:Correct— LLDP only worksbetween directly connected devices.

Option D:Incorrect — not all clients support LLDP; however, the question asks forlimitations of using LLDP, not lack of support.

WhenMarvis Actionsdisplay “AI Validated,” it indicates the issue was detected earlier but is nowresolved.

Marvis automatically validates remediation and marks the action closed once the anomaly clears.

In anEVPN-VXLAN fabric, thecontrol planeoperates overBGP EVPNand is responsible for distributing endpoint reachability information (MAC and IP) among VTEPs. Thedata plane, by contrast, performs encapsulation and forwarding.

“The EVPN control plane uses BGP to exchange MAC and IP address reachability information between VTEPs, enabling efficient forwarding and loop prevention without relying on flood-and-learn behavior.”

Option A:Incorrect — encapsulation occurs in thedata plane, not the control plane.

Option B:Correct — the control plane distributesMAC-to-VTEP mappings.

Option C:Correct — the control plane also distributesIP-to-MAC associations(Type 2 and Type 5 EVPN routes).

Option D:Incorrect — the control plane does not alter packet headers.

When a switch is claimed into a Mist organization, it appears in one of several states depending on connectivity and site assignment.

“After claiming, switches initially appear asUnassignedif they are not yet linked to a site. Once online and connected to Mist Cloud, they transition toConnectedstatus and begin receiving configurations and telemetry.”

Option A (Connected):Correct— indicates the switch is online and communicating with Mist Cloud.

Option B (Inactive):Incorrect — not a valid device state in Mist.

Option C (Active):Incorrect — “Active” is not a device state label in Mist.

Option D (Unassigned):Correct— indicates the switch has been claimed but not yet assigned to a site.

Juniper Mist Wired AssuranceprovidesAI-driven operational visibilityfor EX and QFX switches. It defines and tracksService Level Expectations (SLEs)across multiple performance areas including connectivity, throughput, and switch health.

“Wired Assurance uses AI and telemetry to deliver operational visibility, track service level expectations (SLEs), and monitor throughput, successful connects, and switch health through pre- and post-connection metrics.”

Option A:Correct— accurately describes the full scope of Wired Assurance.

Option B:Incorrect — Wired Assurance provides SLEs specifically for EX and QFX switches.

Option C:Incorrect — both pre- and post-connection SLEs are monitored.

Option D:Incorrect — Wired Assurance monitors both connectivity and device health.

According to the provided exhibit, several visual indicators confirm the operational status and compliance of the EX4100-48MP switch within the Juniper Mist dashboard1.

First, the statement that PoE is enabled is verified by multiple sections of the dashboard2. In the Front Panel view, several ports display a green icon representing a wireless access point, and the PoE status indicator in the top right is lit green, indicating the subsystem is active. Furthermore, the Statistics panel shows a "Total Power Draw" of 48.40 W, and the Metrics section displays "100% PoE Compliance," confirming that the switch is successfully delivering Power over Ethernet to connected devices such as the three Mist APs listed in the summary.

Second, the exhibit indicates that the Junos OS version on this switch is not compliant with the other switches in the site5. This is explicitly shown in the Metrics section, where the Version Compliance tile is highlighted in red with a value of 0%6. In the Mist AI-driven interface, a red compliance tile signifies that the current software version running on the device (identified as 23.2R1.13 in the Properties panel) does not match the "Configured Version" or the "Approved Version" set at the Site or Organization level.

The other options are incorrect based on the visual evidence. While Mist APs are connected, the Front Panel shows them connected to 2.5GbE (mGig) ports (ports 0, 2, 8, etc.) and standard 1GbE ports, not specifically just "ge" interfaces in a traditional sense8. Additionally, the 0% Version Compliance score directly contradicts the idea that the switch is compliant with the organization's standards.

Juniper’s official Campus Fabric IP Clos designfor Mist Wired Assurance defines that the3-stage IP Clostopology eliminates the traditionaldistribution layerentirely. This architecture is intended for smaller campus environments that do not need an intermediate distribution layer between the access and core.

“Juniper’s Wired Assurance supports 3-Stage and 5-Stage IP Clos deployments. The 3-Stage IP Clos is targeted towards deployments that do not require a Distribution Layer and have smaller scale requirements.”

Because the distribution layer is not present, the only hierarchical connection in a 3-stage campus fabric is between thecore and access layers. Traffic is routed directly at the access layer, and each access switch acts as a Layer-3 gateway (IRB) for its VLANs.

“In a campus fabric IP Clos architecture, Mist provisions Layer-3 (L3) integrated routing and bridging (IRB) interfaces on the access layer. All the access switches are configured with the same IP address for each L3 subnet.”

Additionally, the Juniper documentation explains that point-to-point links are configuredbetween layers, and in the case of the 3-stage design (with no distribution), this means between thecore and accessdevices:

“The point-to-point links between each layer utilize /31 addressing to conserve addresses.”

Therefore, the correct statement isC: The core layer is connected to the access layer.

OptionsAandBincorrectly mention a distribution layer that does not exist in this topology.

OptionDis incorrect because core (spine) devices in a Clos fabric are not interconnected with each other.

Juniper Mist AI collectstelemetry for Service Level Expectations (SLEs)across wired and wireless devices. This telemetry includes metrics such as time-to-connect, throughput, coverage, and switch performance.

“Service Level Expectation (SLE) data is collected from every device and stored for up toone monthin the Mist Cloud. This allows administrators to analyze historical performance trends and troubleshoot issues based on real-time and historical data.”

Option B (2 months):Incorrect — data is not retained this long.

Option C (7 days):Incorrect — telemetry retention is longer.

Option D (24 hours):Incorrect — too short for Mist SLE analytics.

Option A (1 month):Correct — Mist Cloud retains SLE telemetry for30 days (1 month).

During campus fabric deploymentin Mist AI, switches are onboarded usingclaim codesand must beassigned to the correct siteandonlineso that Mist can push configurations and validate connectivity.

“All switches to be included in a campus fabric must be claimed, online, and assigned to the target site before launching the Campus Fabric wizard. Mist Cloud automatically discovers their roles and builds the topology.”

Option A:Incorrect — switches must be site-assigned before fabric creation.

Option B:Correct— switches must beonlineto receive configurations from Mist.

Option C:Incorrect — offline devices cannot be configured or validated in the fabric wizard.

Option D:Correct— switches must beassigned to the correct sitefor topology creation.

According to theJuniper Mist AI for Wired – Campus Fabric IP Clos Deployment Workflow, deploying a campus fabric involves a defined sequence of planning and configuration steps within the Mist Cloud interface. The key stages include:

“To deploy a campus fabric, you must first define the topology type, identify the physical connections between devices, and define the networks of interest that will be extended across the fabric.”

Breaking this down:

Choose the topology (D):Selecting the correct fabric type (3-Stage or 5-Stage IP Clos) determines how access, distribution, and core switches will interconnect.

Define the physical connections (A):This step involves specifying the uplink and downlink relationships between switches so that Mist can auto-generate EVPN-VXLAN and routing configurations.

Define the networks of interest (B):These are the VLANs and subnets that need to be extended across the fabric for user and device connectivity.

Steps such asconfiguring DNS serversordefining GBP tagsarenot part of the campus fabric deployment workflowin Mist Wired; they are optional or separate configurations outside the main deployment flow.