JN0-460 JNCIS-MistAI-Wired Questions and Answers

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.

InMist Cloud,site variablesare used to store and reference common configuration values (such as VLAN IDs, subnet addresses, or gateway IPs) that are reused across multiple devices and templates within a site.

“Site variables allow administrators to define reusable configuration parameters that can be referenced in multiple templates or device configurations, ensuring consistency and reducing manual errors.”

Option A:Incorrect — applies configuration directly, not reusable references.

Option B:Correct— site variables enable you to reference the same VLAN or value in multiple configurations (switches, WLANs, etc.).

Option C:Incorrect — WLAN templates are for wireless SSID configuration.

Option D:Incorrect — switch templates define static configuration but don’t store shared variables.

Aport negotiation mismatchoccurs when the local and remote interfaces fail to agree on common speed or duplex settings.

Marvis Wired Assurance automatically detects this by analyzing telemetry from the switch’s physical interfaces.

You can resolve this by ensuringauto-negotiationis enabled on both ends (A) and verifying the peer device supports the802.3 autonegotiation standard(D).

Manually forcing half-duplex or replacing hardware is unnecessary unless the hardware is faulty.

“Marvis Wired Actions correlate interface negotiation errors with LLDP neighbor data to pinpoint mismatched configurations, helping administrators quickly verify speed/duplex compatibility and 802.3 autonegotiation support.”

InJuniper Mist Wired Assurance, SLEs (Service Level Expectations) measure key performance indicators for wired network quality.Throughput SLEmonitorsdata transfer quality, includinglatency, jitter, and packet loss, which directly impact real-time applications such as voice or video.

“The Throughput SLE provides visibility into end-to-end network performance by tracking latency, jitter, and packet loss, helping identify congestion or quality issues across wired connections.”

Option A (Throughput):Correct— this SLE includes jitter measurement.

Option B (Successful Connect):Tracks client connection success rate, not jitter.

Option C (Capacity):Monitors link utilization and load, not jitter.

Option D (Switch Health):Monitors device hardware and software health, not traffic performance.

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.

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.

According to Juniper Networks' EVPN documentation, an EVPN Type 4 route, also known as an Ethernet Segment route, is a critical component of the BGP EVPN control plane used specifically in multihoming scenarios. When a Customer Edge (CE) device is connected to two or more Provider Edge (PE) routers via a Link Aggregation Group (LAG), these PE routers must coordinate to manage traffic flow and prevent network loops.

The primary purpose of the Type 4 route is to enable Designated Forwarder (DF) election. In a multihomed Ethernet Segment (identified by a unique Ethernet Segment Identifier or ESI), only one PE router—the Designated Forwarder—is permitted to forward Broadcast, Unknown unicast, and Multicast (BUM) traffic from the EVPN core to the CE device. Without this election process, multiple PE routers would forward the same BUM packets to the CE, leading to traffic duplication and potential broadcast storms.

The workflow begins when a PE router is configured with an ESI on a physical or logical interface; it then generates and advertises a Type 4 route to all other PE routers in the network. This route carries the ESI and an "ES-import" extended community, which allows other PEs connected to the same segment to automatically discover their peers. Once these "peering" PEs are discovered, they collectively execute a DF election algorithm—such as the default modulo-based algorithm or the newer preference-based algorithm—to select the DF and Backup Forwarder (BDF) for each VLAN or bridge domain. By ensuring a deterministic and synchronized selection of the forwarder, Type 4 routes provide the foundational stability required for active-active and active-standby multihoming in modern campus and data center fabrics.

ForJuniper cloud-ready EX Series switches(EX2300, EX3400, EX4100, EX4400, etc.) to successfully onboard to theJuniper Mist Cloud, specific connectivity requirements must be met:

“Cloud-managed EX switches require outbound connectivity to the Mist Cloud on TCP ports 2200 or 443. Switches must also have access to DNS services to resolve cloud service URLs during onboarding.”

Option A:Incorrect — minimum version depends on switch model; older models may onboard with earlier releases (e.g., 20.x, 21.x).

Option B:Correct— outbound TCP 2200 or 443 connectivity is required for cloud registration.

Option C:Incorrect — switches connect directly to Mist Cloud, not the Agile Licensing Portal.

Option D:Correct— DNS resolution is mandatory for discovering Mist Cloud endpoints.

According to Juniper Mist documentation, Wired Service Level Expectations (SLEs) are designed to provide operational visibility into the wired experience by monitoring Juniper EX and QFX Series switches. These SLEs leverage pre-connection and post-connection performance metrics to ensure network reliability and performance.

Pre-connection metrics are specifically focused on the initial phase of a client's journey to join the network. These metrics show the total number and the time required for successful connects and authentication. By tracking 802.1X events and DHCP snooping data, Mist can identify if clients are failing to onboard due to RADIUS issues, authentication timeouts, or failures in the DHCP binding process. This allows administrators to proactively address onboarding hurdles before they impact the broader user base.

Post-connection metrics, conversely, measure the network experience once a client is already "on the wire" and attempting to pass data. These metrics primarily measure throughput and focus on detecting various network errors and operational anomalies. Specifically, post-connection monitoring detects issues such as Spanning Tree Protocol (STP) loops, interface errors, and congestion. Additional post-connection insights include identifying cable issues, negotiation failures, and MTU mismatches that might occur during active data transmission.

In summary, Juniper Mist divides its telemetry into these two distinct categories to simplify troubleshooting. Pre-connection metrics ensure that users can get on the network, while post-connection metrics ensure that the network can sustain their traffic requirements without errors. This combined approach enables the Mist AI-driven Predictive Analytics and Correlation Engine (PACE) to provide a holistic view of the end-user experience, moving beyond traditional "up/down" monitoring to a deeper understanding of the quality of the client experience.

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.

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.

Syslogis the standard method for exporting Mist AI event and telemetry messages to third-party collectors.

It supports both UDP and TCP delivery for centralized log correlation.

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.

According to Juniper Mist documentation, the EX2300, EX4650, and QFX5120 switches require a specific additional workflow within the Mist portal to form a Virtual Chassis because these models do not have dedicated Virtual Chassis ports (VCPs). Unlike other EX-series models (such as the EX4100 or EX4400) that possess factory-defined, dedicated VCPs and can form a Virtual Chassis automatically upon physical connection, these three platforms require an administrator to explicitly initiate the "Form Virtual Chassis" action from the Mist UI.

This workflow is necessary because the system must logically convert standard network uplink ports into Virtual Chassis ports to enable stack communication. To execute this, the switches must first be onboarded to the Juniper Mist cloud as standalone devices and assigned to the same site. Once they are online and their configuration is managed by Mist, the administrator selects the desired members from the switch inventory and clicks More > Form Virtual Chassis.

During this additional workflow, the Mist portal prompts the user to specify which front-panel ports will be repurposed as VCPs and allows for the manual assignment of member IDs and Routing Engine roles. This "pre-provisioned" method ensures a deterministic setup where roles are not left to chance. Once the command is pushed, the switches reboot to reconfigure their internal hardware logic to treat the selected ports as fabric links. Juniper emphasizes that for these specific models, the "Form Virtual Chassis" option is the only supported way to establish the stack within Wired Assurance, as it ensures that the cloud-native management plane correctly recognizes the multiple physical chassis as a single logical entity.

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.

Within Mist Insights,Client Eventsshow state transitions such asreassociationand IP-level issues likeDHCP Denied.

These help correlate connectivity issues across wired or wireless edge connections.

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.

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.

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.

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.

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-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.