SDWAN enhancements in a satellite link

Due to some event with extreme weather conditions, a customer decided to use satellite links as a last resort in case of failure of optical and radio links.

The use of SD-WAN highlighted some interesting points.

When the satellite link was activated, the first test performed was a speedtest.

The results, even with some tuning, were below the expectations.

After some investigation, the satellite link provider confirmed that the advertised bandwidth of the uplink corresponds to the total amount of parallel streams handled by the equipment.

For the same reason, running an IPSec VPN or SDWAN tunnel would result in lower effective throughput.

Information gathering

After some testing and gathering technical details from the provider, it appears that the satellite link can deliver up to twelve parallel streams simultaneously.

The solution

To accommodate the twelve flows, twelve interfaces, each associated with a dedicated public IP, were created on the SDWAN device.

The SDWAN device takes care of distributing the traffic between the tunnels, with its own balancing algorithms.

End result

In terms of bandwidth, the final result is quite close to the expected troughput.

For link quality, the image below shows how the SDWAN enhancements guarantee a satisfactionary experience even when some flows underperform.

The first line shows traffic performance after improvements. The lines below show in red when each tunnel has high latency or high packet loss.

Scalability

One point of focus for this solution is scalability. Using many interfaces to create parallel tunnels causes the total number of tunnels to increase. The product data sheet gives the maximum recommended number.