Wired Throughput SLE

What Does the Wired Throughput SLE Measure?

This SLE represents the ability of wired users to pass traffic without impedance.

Classifiers

When the throughput 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, less than 1 percent of the issue were attributed to Congestion Uplink, 19 percent to Interface Anomalies, 1 percent to Storm Control, and 80 percent to Congestion. (See the classifier descriptions below the example.)

• Congestion Uplink—The SLE dashboard shows high congestion uplink when:

  • One of the neighbors is a switch or a router (known through LLDP).

  • The port is a Spanning Tree Protocol (STP) root port.

  • The uplink port has a higher number of transmitted and received packets compared to the other ports.

  • Aggregated Links. Congestion can also be caused by aggregated Ethernet links and module ports.

• Interface Anomalies—The details for interface anomalies are all obtained from the switch. The Interface Anomalies classifier contains three sub-classifiers: MTU Mismatch, Cable Issues, and Negotiation Failed.

  • MTU Mismatch—As an administrator, you can set an MTU value for each interface. The default value for Gigabit Ethernet interfaces is 1514 . To support jumbo frames, you must configure an MTU value of 9216, which is the upper limit for jumbo frames on a routed virtual LAN (VLAN) interface. It's important to ensure that the MTU value is consistent along the packet's path, as any MTU mismatch will result in discarded or fragmented packets. In Juniper Networks switches, you can check for MTU mismatches in the MTU Errors and Input Errors sections of the show interface extensive command output. Each input error or MTU error contributes to a "bad user minute" under MTU mismatch.

  • Cable Issues—This sub-classifier shows the user minutes affected by faulty cables in the network.

  • Negotiation Failed—Latency on ports can happen due to autonegotiation failure, duplex conflicts, or user misconfiguration of device settings. Moreover, older devices may fail to achieve maximum speed and could operate at a slower link speed of 100 Mbps. This sub-classifier identifies and helps mitigate instances of bad user time caused by these issues.

• Storm Control—Storm control allows the device to monitor traffic levels and drop broadcast, unknown unicast, and multicast packets when they exceed a set threshold or traffic level. This threshold is known as a storm control level or storm control bandwidth. The default storm control level is 80 percent of the combined broadcast, multicast, and unknown unicast traffic on all Layer 2 interfaces of Juniper switches. Storm control helps prevent traffic storms, but it can also potentially throttle applications or client devices. This classifier identifies these conditions and helps users proactively mitigate throughput issues.

• Congestion—This classifier measures the number of output drops. When packets come into a switch interface, they are placed in an input queue (buffer). When the buffer becomes full, it will start to drop packets (TxDrops). We use a formula that takes into account the following ratios to determine if there is a 'bad user minute' due to congestion:

  • TxDrops to TxPackets—Total transmitted bytes dropped to total packets transmitted.

  • Txbps to Link speed—Total bytes transmitted per second to link speed.

  • RxSpeed to Link speed—Total bytes received per second to link speed.