Understanding the switch mechanism and how links are chosen
When each metric is measured or calculated, a score is calculated for every link: this involves comparing the last measurement (latency) or last metric calculation (jitter or packet loss rate) with the value set in the SD-WAN SLA.
The link that obtains the best score is chosen to transport traffic.
In a four-link configuration (two main links and two backup links), the table below shows how the links will be chosen based on their respective status at a given moment, and based on the chosen configuration (whether there is load balancing, threshold values, etc.):
Legend
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Optimal link | |
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Degraded link (does not meet SLA thresholds) | |
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Highly degraded link (when several links are degraded : link with the lowest score) | |
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Link not available |