There are some issues with the way FreeSWITCH changes candidate pairs
based on connectivity checks. That generally manifests as: 1) an asymmetric
start time between inbound and outbound audio (eg inbound audio takes 20
seconds to come in while outbound works right out of the bat
2) wrong pairs being picked initially and FS taking longer
than ideal to find a new one 3) 1006s, 4) ....
This backports signalwire PR 1914 in an attempt to mitigate
the aforementioned issues. The PR description explains the rationale
rather well and seems sound. I've tested this in demo servers with midly
satisfying results, but still needs further testing.
1e9834687e