Free Juniper JN0-253 Practice Exam with Questions & Answers

Dynamic Port Configuration (DPC)inJuniper Mist Wired Assuranceallows EX Series switches to automatically assign port profiles, VLANs, and policies to connected devices based on their unique identifiers. This automation simplifies switch management and ensures consistent configurations across distributed networks.

According to theJuniper Mist Wired Assurance Configuration and Dynamic Port Management Guide:

“Dynamic Port Configuration matches connected endpoints using identifiers such as LLDP chassis ID and MAC address to assign the appropriate port profile or VLAN automatically.”

LLDP Chassis ID (C):Identifies the connected device by its LLDP advertisement, often representing a switch, phone, or AP.

MAC Address (D):Provides unique device identification, ensuring precise port and VLAN assignment even when LLDP data is unavailable.

OptionsA (Serial Number)andB (IP Address)are not used for port configuration matching in DPC because they are not always available at the time of link establishment.

Therefore, the correct answers areC. LLDP Chassis IDandD. MAC Address.

Juniper Mist Cloud provides visual and automated notifications to alert administrators aboutsubscription status and expirationfor services such asWireless Assurance, Wired Assurance, WAN Assurance, Premium Analytics, and Marvis AI.

According to theJuniper Mist Cloud Administration and Licensing Guide, the system:

“Displays subscription and license expiration warnings in a banner across the top of the Mist portal interface when licenses are within their renewal window.”

This banner typically appears in yellow or red, depending on urgency, and includes direct links to theSubscriptionspage for renewal actions.

While subscription status information can also be viewed manually underOrganization → Subscriptions, thereal-time reminders and notificationsappear asbanner messages at the top of the Mist Portal.

OptionsB,C, andDare incorrect because:

Dashboard alerts focus on network events, not licensing.

Marvis Actions highlights operational or performance issues.

Device insights report performance metrics, not subscription data.

Therefore, the correct answer isA. In a banner message at the top of the Juniper Mist portal.

Marvis Minisis an advanced feature within the Juniper Mist AI ecosystem designed to performautonomous, synthetic network testing. It uses Mist Access Points (APs) to simulate client behavior—such as association, authentication, DHCP, DNS, and application reachability—to proactively detect service issuesbefore real users are affected.

According to theJuniper Mist Marvis Minis Deployment GuideandMarvis AI documentation, the key requirement for enabling Marvis Minis is that all participating access points must be running aminimum supported firmware versionthat includes the Minis agent functionality.

The documentation specifies:

“Marvis Minis requires APs running the minimum firmware version that supports synthetic testing. APs on earlier versions will not be capable of running Minis tests or reporting results to the Mist Cloud.”

Additional subscriptions such asWAN Assurance,Premium Analytics, orWLAN templatesare not prerequisites for operation. WhileMarvis licensingmust be active, the feature itself relies primarily on compatible firmware within the Mist-managed APs.

Therefore, the correct answer isC. Minimum AP firmware— ensuring the APs are on a supported firmware release is essential for Marvis Minis functionality.

In theJuniper Mist Cloud architecture, data is collected and streamed from variousedge devicesto the Mist Cloud platform, whereAI-driven analytics,automation, andtelemetry correlationoccur. OnlyMist-managed devicesthat are cloud-connected contribute operational telemetry data to Mist AI for analysis.

According to theJuniper Mist Cloud Architecture and Operations Guide:

“Access Points, Juniper Mist Edge devices, and Session Smart Routers (SSR) communicate directly with the Mist Cloud, sending telemetry, configuration, and analytics data in real time.”

Access Points (B):Provide wireless client telemetry, RF statistics, and user SLE (Service Level Expectation) data.

Session Smart Routers (C):Supply WAN Assurance and routing analytics, including path and session health data.

Juniper Mist Edge (D):Acts as an on-premises gateway that forwards data and enables local breakout for Mist Cloud services.

Syslog ServersandRADIUS Serversare external systems and do not send native telemetry to the Mist Cloud—they only interact through authentication or logging integrations.

The WAN Edge Health SLE in Juniper Mist monitors critical operational metrics for WAN edge devices. According to Juniper’s documentation: “Juniper Mist analyzes various factors that affect WAN edge health and assigns a score… Classifiers include Memory—triggered when WAN edge memory utilization is above 80 percent and CPU—triggered when control or data plane CPU utilization is above 90 percent.” These components directly impact the device’s ability to process traffic. Monitoring these parameters enables rapid detection of system resource constraints, which are essential for ensuring optimal WAN performance. While ISP reachability is a separate SLE (usually part of WAN Link SLEs), application response times are tracked in Application SLEs.

TheJuniper Mist Cloud APIfollowsRESTful API design principles, enabling programmatic access to all Mist Cloud functions such as device management, configuration, analytics, and monitoring. REST APIs in Mist use a lightweight and standardized data exchange format to facilitate seamless integration with third-party applications and automation frameworks.

According to theJuniper Mist API Developer Guide:

“All Juniper Mist Cloud API requests and responses are transmitted in JavaScript Object Notation (JSON) format. JSON is used because it is lightweight, easy to parse, and compatible with all modern programming environments.”

JSON is the preferred format because it is both human-readable and machine-efficient, allowing for fast serialization and deserialization of data structures.

Other formats such asCSV,XML, andYAMLare not used for API communication within the Mist Cloud architecture.

Therefore, the correct answer isD. JSON.

Alerts represent network and device issues that are ongoing. Juniper Mist™ categorizes them as follows:

Infrastructure Alerts—Repeated events involving servers and protocols that can potentially affect a large number of clients. For example, an event during which a Domain Name System (DNS), Dynamic Host Configuration Protocol (DHCP), or RADIUS server is unreachable can affect many clients. Similarly, if a power supply on a switch is in alarm state, a large number of clients and a large amount of traffic could be affected.

Marvis Alerts—Repeated events that Marvis tracks on the Marvis Actions dashboard. For example, if an access point (AP) regularly fails health checks, you'll see a Marvis alert for it.

Security Alerts—Repeated events that could dramatically affect network security. For example, these alerts appear if a rogue AP is detected and clients start connecting to it.

Certificate Alerts—Notification for expired, and soon-to-expire, user-added digital certificates. These include RadSec (configured at Organization > Settings > RadSec Certificates and AP RadSec certificate), SSO (configured at Organization > Settings > Single Sign-On), and PSK Portal IDP certificates (configured at Organization > Client Onboarding). Certificate alerts appear on the Alerts page and begin 30 days before the certificate's expiry date, then the notification repeats 15, 7, 3, and 1 day before expiration unless the certificate is renewed. .

https://www.juniper.net/documentation/us/en/software/mist/mist-aiops/topics/concept/alerts-overview.html

Comprehensive and Detailed Explanation verified by Juniper Mist documentation:

To ensure a guest WLAN is available only on a specific lobby AP, the correct approach according to Juniper Mist best practices is to create a new "Guest" WLAN template and add it to the lobby AP using a device profile. This method leverages device profiles for targeted SSID airtime availability, allowing granular WLAN assignment to selected APs (not all APs or sites). Juniper's documentation and solution briefs confirm that device profiles control which SSIDs broadcast on specific access points within a site, supporting scenarios like dedicated guest access only in particular areas such as the lobby.

Creating WLANs in standard templates enables SSID broadcast across all assigned APs, not selectively per device. Organization labels do not restrict SSID broadcast for individual APs.

Verification:

Your selected answer in the image ("Create a new 'Guest' WLAN template and add it to the lobby AP using a device profile") is correct and aligns with Juniper's recommended workflow.

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Thesession policy settingsin theJuniper Mist Clouddefine how long a user session remains active and how the system manages session expirations due to inactivity. These configurations help ensure bothsecurityandefficient resource managementacross the Mist Cloud portal and API sessions.

According to theJuniper Mist Cloud Administration and Security Configuration Guide:

“Session policy defines session timeout and inactivity timeout parameters, controlling how long users can remain logged into the Mist Cloud portal or API before re-authentication is required.”

Session Timeout:Specifies the maximum duration a session can remain active, regardless of activity.

Inactivity Timeout:Defines how long a session can remain idle before automatic logout.

These policies help maintain strong access security by reducing the risk of unauthorized access through stale sessions.

Other options such as password complexity (A, C) and two-factor authentication (D) are configured underauthentication and access policies, not session policies.

Therefore, the correct answer isB. The duration for session timeout and inactivity timeout.

Juniper Mist delivers Automatic Feature Updates, Wireless Assurance, and Asset Tracking as core platform features.

Automatic feature updates: As part of its cloud architecture, Juniper Mist provides bi-weekly, hitless automatic updates for features and security, delivered seamlessly from the cloud without service interruption or manual intervention. Mist documentation states, "New features, security patches, and updates are automatically added on a bi-weekly basis without interruptions or service downtime. This dramatically simplifies and improves service operations for network IT administrators."

Wireless Assurance: Wireless Assurance is Mist’s flagship cloud service that leverages AI and machine learning to automate wireless network operations, delivering predictable, reliable, and measurable Wi-Fi experiences. It provides deep visibility into client states, sets service level expectations (SLEs), and uses Marvis actions and AI-driven recommendations to ensure root-cause identification and proactive troubleshooting—"Mist Wi-Fi Assurance is a cloud service based on machine learning (ML) and driven by Mist AI... designed for the smart device era."

Asset tracking: Asset Visibility/Tracking uses vBLE technology and Wi-Fi to track and locate assets and IoT devices within an organization, integrating with Juniper Mist Cloud for real-time and historical analytics. According to the Asset Visibility datasheet: "Mist Asset Visibility is a cloud service that enables real-time tracking and historical location analytics of people, assets, and IoT devices."

Controller firmware updates and perpetual AP licenses are not listed features of the Mist cloud architecture; Mist uses a cloud-based control plane and subscription-based licensing for its platform.