4 ms·

TCP is self correcting. So in the end the receiver gets the whole data, correctly. But it happens with a delay. For audio you need real-time synchronous data f

TCP is self correcting. So in the end the receiver gets the whole data, correctly. But it happens with a delay. For audio you need real-time synchronous data feed, and cannot wait for the error correction round trip to happen.

fulafel 7y ago
That's what I meant by unusable. Web browsing[1] is unusably slow if you have these packet loss rates. Look at eg p6 graph here: https://netcraftsmen.com/wp-content/uploads/2014/12/20120410_Impact-of-packet-loss.pdf https://netcraftsmen.com/wp-content/uploads/2014/12/20120410... [1] and other non-interactive apps like social media
- cma 7y ago
  It may be the "jitter and other delays". They don't necessarily slow down browsing as much as packetloss. I think modern wifi causes a huge amount of it when other people in the same freq are using lots of bandwidth and it doesn't necessarily manifest as loss.
  - trevyn 7y ago
    Right, if a packet gets delayed by 400ms, that's not going to break TCP, but you might as well consider it dropped for a real-time call.
    - fulafel 7y ago
      If it's frequent (3-20pct), it's going to break your web browsing experience on TCP too because it had to be retransmitted. The original eventually appearing 400ms later doesn't make a difference.
      - cma 7y ago
        Main threshold is if it is beyond RTT or not. But if it is 20pct frequent, there's 4% that are held up and then have their retransmission held up too. Back to voice, many voice codecs will do forward error correction, but if jitter affects multiple packets in the sequence similarly instead of being independent that might not be enough.
vbezhenar 7y ago
IMO you absolutely can wait for round-trips, etc. The problem arises when delay is not consistent. But if the delay is consistent, it's not a big problem. When I was child and called my relatives in another country, that's how it worked and it never was a big problem. It's absolutely better than discard data and tear voice apart. So the software should select appropriate delay for current network conditions and slowly change it if necessary.
- C1sc0cat 7y ago
  You needed to know the dialling hack to force it via cable rather than satellite. I think it was adding an extra digit to the dialled number - I have forgotten the details as it was a long time ago

fulafel 7y ago

That's what I meant by unusable. Web browsing[1] is unusably slow if you have these packet loss rates. Look at eg p6 graph here: https://netcraftsmen.com/wp-content/uploads/2014/12/20120410_Impact-of-packet-loss.pdf https://netcraftsmen.com/wp-content/uploads/2014/12/20120410... [1] and other non-interactive apps like social media

cma 7y ago
It may be the "jitter and other delays". They don't necessarily slow down browsing as much as packetloss. I think modern wifi causes a huge amount of it when other people in the same freq are using lots of bandwidth and it doesn't necessarily manifest as loss.
- trevyn 7y ago
  Right, if a packet gets delayed by 400ms, that's not going to break TCP, but you might as well consider it dropped for a real-time call.
  - fulafel 7y ago
    If it's frequent (3-20pct), it's going to break your web browsing experience on TCP too because it had to be retransmitted. The original eventually appearing 400ms later doesn't make a difference.
    - cma 7y ago
      Main threshold is if it is beyond RTT or not. But if it is 20pct frequent, there's 4% that are held up and then have their retransmission held up too. Back to voice, many voice codecs will do forward error correction, but if jitter affects multiple packets in the sequence similarly instead of being independent that might not be enough.

vbezhenar 7y ago

IMO you absolutely can wait for round-trips, etc. The problem arises when delay is not consistent. But if the delay is consistent, it's not a big problem. When I was child and called my relatives in another country, that's how it worked and it never was a big problem. It's absolutely better than discard data and tear voice apart. So the software should select appropriate delay for current network conditions and slowly change it if necessary.

C1sc0cat 7y ago
You needed to know the dialling hack to force it via cable rather than satellite. I think it was adding an extra digit to the dialled number - I have forgotten the details as it was a long time ago