On Fri, 4 Jan 2019, Dave Taht wrote:
dsl interleave was added primarily to make multicast udp tv streams work better (as they are very intolerant of packet loss). Often (as in free's implementation) these streams are "invisible" to the overlying IP applications. It typically adds at least 6ms of delay to an already slow technology.
ADSL2+ is very prone to short bursts of interference, so setting no interleaving means quite high packet loss. Setting interleaving to 16ms means FEC has a much better chance of correcting errors and thus reduce packet loss.
At several jobs ago we actually had several different profiles for customers, they could choose 1, 4 or 16ms interlaving depending on their needs for gaming etc. The 1 and 4 ms interleaving targets had different SNR margin targets so they were sacrificing speed for lower latency, because that's the tradeoff you basically have to do with normal L4 protocols that end customers typically use.
-- Mikael Abrahamsson email: swm...@swm.pp.se _______________________________________________ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat
