Switch Health SLE
SUMMARY Use the Switch Health SLE to assess switch performance and to identify user-impacting issues with switch reachability, memory, CPU, and more.
Switch Health is one of the Service-Level Expectations (SLEs) that you can track on the Wired SLEs dashboard.
To find the Wired SLEs dashboard, select Monitor > Service Levels from the left menu of the Juniper Mist™ portal, and then select the Wired button.
What Does the Switch Health SLE Measure?
Juniper Mist™ monitors your switches' operating temperatures, power consumption, CPU, and memory usage. Monitoring switch health is crucial because issues such as high CPU usage can directly impact connected clients. For instance, if CPU utilization spikes to 100 percent, the connected APs may lose connectivity, affecting the clients' experience.
Classifiers
When the Switch Health threshold is not met, Juniper Mist sorts the issues into classifiers. The classifiers appear on the right side of the SLE block. In this example, 82 percent of the issues are attributed to Switch Unreachable and 12 percent to System. (See the classifier descriptions below the example.)
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Switch Unreachable—The switch can't be accessed.
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Capacity
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ARP Table—Usage exceeded 80 percent of the Address Resolution Protocol (ARP) table capacity.
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Route Table—Usage exceeded 80 percent of the routing table capacity.
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MAC Table—Usage exceeded 80 percent of the MAC table capacity.
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Network—You can use this classifier to monitor user minutes when the throughput is lower than expected due to uplink capacity limitations. It identifies issues based on the round-trip time (RTT) value of packets sent from the switch to the Mist cloud. The Network classifier has two sub-classifiers that help you identify these issues:
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WAN Latency—Displays user minutes affected by latency. The latency value is calculated based on the average value of RTT over a period of time.
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WAN Jitter—Displays user minutes affected by jitter. The jitter value is calculated by comparing the standard deviation of RTT within a small period (last 5 or 10 minutes) with the overall deviation of RTT over a longer period (day or week). You can view this information for a particular switch or site.
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System
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CPU—The CPU usage of the switch is above 90 percent.
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Memory—The memory utilization is above 80 percent.
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Temp—The operating temperature of the switch is outside the prescribed threshold range, going either above the maximum limit or below the minimum requirement.
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Power—The switch is consuming over 90 percent of the available power.
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