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Service-Level Experiences for Session Smart Router Deployed as WAN Edge

Get familiar with Service Level Expectations (SLEs) for Juniper® Session Smart™ Routers deployed as WAN edge device and learn more efficient ways to monitor your WAN edge device in the Juniper Mist™ portal using SLE insights.


The Juniper SD-WAN driven by Mist AI WAN Assurance solution simplifies the way you monitor your WAN edge. Session Smart™ and SRX Series WAN edge devices have unique implementations for tracking metrics for WAN Edge health, WAN link health, and application health to derive percentage ratings, which Juniper calls user minutes. User-minute metrics inform the basis for Mist monitoring and Juniper service-level experiences (SLEs). Using critical metrics on application response times, WAN link status, gateway health, and other network conditions, both the SRX Series and Session Smart WAN edge devices gain insights into how these metrics impact end-user experiences and use them to identify the root causes of any service degradation. You can find an overview of all Mist SLEs here:

In this troubleshooting section of the configuration guide, you'll discover SLEs specific to your WAN edge.

Session Smart WAN Edge SLEs

Read the Session Smart WAN Edge SLE guide to learn how to use the Juniper Mist dashboard to efficiently diagnose device and WAN connectivity issues following your initial deployment phase. Let's first focus on WAN edge service-level expectations (SLEs).

Starting at the Juniper Mist dashboard, navigate to Monitor > Service Levels.

  1. Select Monitor > Service Levels from the Juniper Mist dashboard.
  2. From the site list, select a WAN Edge you want to inspect SLEs for. In this example, select Dallas-Fullstack.
  3. Click the WAN tab and select the WAN edge you want to investigate. For example, lab1-dallas.

    Note: Metrics for WAN SLEs do not get populated immediately. SLEs require a dataset to pull information for the Edge Health, Link Health, and Application Health metrics. Your Monitor screen may not display anything if you’ve just onboarded the device. A week of information is expected before SLEs can be leveraged in a production environment. For your environment, try changing the time next to the site drop-down menu to a shorter period—for example, the last 60 minutes, but it still may not represent any data.

    The first infographic on your WAN SLE page displays the relationship.

  4. Click the toolbox icon to select from a menu in which system changes are displayed.

    Your WAN edge SLEs are displayed in the SLE Success Rate default view.

    Select a site to inspect and select the WAN edge you’re investigating. In this example, we’re looking at the lab1-dallas WAN edge. The first infographic on your WAN SLE page displays the relationship between collected clients at a point in time and system events that occurred during that same window. The SLE Success Rate default view is just beneath the client insights on your WAN SLE page.

    You can also toggle the view to Values for a numerical display of SLE metrics. It’s important to familiarize yourself with the Settings button.


    There’s little customization to this dialog box for Settings on the Session Smart Router. The Secure Vector Routing protocol measures these values automatically based on metadata exchanged. You do need SLE Application probes set on SRX Series devices.


For these SLEs, note that the system works to reduce the need for administrators to watch for anomalies. Instead, Juniper(r) Mist WAN Assurance defines threshold levels after which the administrator is notified. This approach contrasts with traditional models where the system administrator would define these values based on a curve or pattern observed.

Our First WAN SLE is WAN Edge Health

WAN Edge Health

The WAN Edge Health SLE provides platform metrics that comprise the root cause analysis for the Service Level metric, including power, CPU and memory utilization, WAN Edge disconnects, and platform temperature.

WAN Edge Health

WAN Link Heath

Use the WAN Link Health SLE to know more about the interfaces and where or to which devices they connect.

The next WAN SLE is WAN Link Health. Now, we’re looking at information on your interfaces and where they connect. These metrics comprise the Root Cause Analysis for the WAN Link Health metric. Data for WAN Link Health comes from these classifiers:

  • Network
    • The Session Smart WAN edge monitors Jitter, Loss, Latency, and Session Smart Peer Path Down status via Secure Vector Routing.
  • Interface
    • The Interface category monitors your LTE Signal strength, Cable Issues, and Congestion.
  • ISP Reachability
    • ISP Reachability comprises ARP and DHCP success.

Application Health

Your last WAN SLE is Application Health. Here’s where it gets interesting. In this lab environment, Application Health has a 79% rating, which means applications hit the service expectations 79% of the time. Like the other values, you can dive into where and why the metrics in the Root Cause Analysis comprise a particular Application Health score with these classifiers:

  • The amount of jitter that contributes to the Root Cause Analysis score.
  • The amount of loss that contributes to the Root Cause Analysis score.
  • The amount of latency that contributes to the Root Cause Analysis score.
  • Failed application health contributes to the Application Services Root Cause Analysis score.
Application Health

Troubleshooting the Session Smart WAN Edge with SLE Insights

To troubleshoot the Session Smart WAN edge with SLE insights, select Monitor > Service Levels from the Juniper Mist dashboard, select Monitor > Service Levels.

Let’s learn how to investigate the WAN edge SLEs. We’ll dive into Application Health Monitoring for this troubleshooting guide to get detailed metrics. But each SLE menu—WAN Edge Health, WAN Link Health, and Application Health—displays similar tables and tabs related to the SLE. You'll often look at application health while troubleshooting.


Remember that you don’t need to define Application probes for Application SLEs on your Session Smart WAN edge like you do on an SRX Series device. However, you will need traffic that can be sampled and reported to the Juniper Mist cloud. Juniper Mist AI requires data for suggestions and decisions like any AI-based system. The best practice for this is to collect results from an entire week. However, you’ll get the first data after 24 hours.

What does a generalized Success Rate of 91% for Application Health mean for your network? The Application Health pane reveals a percentage comprised of the Root Cause Analysis that includes all the previously mentioned classifiers (latency, jitter, loss, and application failures) for an overall percentage. When you dig into the menu below, you’ll find a few tabs that give you deeper insights into the classifiers that didn’t meet expectations.

  • The Statistics tab on the Application Health pane displays the generalized percentage of all the classifiers.
  • The Timeline tab is a chronological display of events comprising the classifiers, listing their failures, connected clients, and system changes. The time frame is influenced by the value at the top of the page, with options for Today, Yesterday, TThis Week, or a Custom Range. On the timeline, you can select a specific time, zoom in for details, or select a range. Hovering over a point in time will outline the classifier that failed to meet service expectations.
  • The Distribution tab analyzes service-level failures by attribute and is sorted by the most disruptive attribute. You can drill down into categories of traffic classes, peer paths (those Session Smart connections between Session Smart Routers), physical interfaces, WAN edges, and zones. Note that WAN Assurance deployments with Session Smart WAN edge devices leverage the peer path information, while the SRX Series WAN edge leverage destination zones for deeper insights in the Distribution tab.
  • The Affected Items tab categorizes the specific items that failed to meet service-level goals. Here, you’ll find a numerical value for the applications, interfaces, clients, WAN edges, or categories that failed.