Hi, I used to work for a satellite ISP, and if I'm not mistaken Xplornet is buying bandwidth of my previous employer. That does not mean that your friend is on the same service. Where I worked, phy transmissions are scheduled based on tokens. A UT must have a token to transmit data. If there is no congestion, a token will be available and the UT or ground station may transmit. Congestion does not need to exist in the ground network or even the transponder. It can even be in the spectrum of that geographical area. To overcome the latency, a few things are done: - prefetching on the UT - WAN acceleration on the UT and in the network (basically syn/ack spoofing) and a few other proprietary things. Satellite is obviously not the optimal medium for video conferencing, but I would recommend that your friend tries to ratelimit their transmissions. The reason why your latency is higher than you expect, is because you expect latency to be equivalent to the round-trip time from earth to GEO and back. However, most of the time your UT will not be with the shortest line-of-sight, meaning the distance is longer. Also, the satellite merely acts as a smart mirror, and the traffic must still be backhauled from a groundstation to a processing location. They can also be several tens of milliseconds away. Then they must follow their normal path along the internet. Ping me off-list if you have specific questions. Thanks, Sabri ----- On Apr 21, 2020, at 4:58 AM, Brian J. Murrell brian@interlinx.bc.ca wrote:
A friend of mine just recently got Xplornet satellite service at his rural home. I'm well aware of the latency issues with satellite although frankly his latency is much better than I had feared it would be and is around 600-700ms.
But what seems to be worse than the latency is the "burstiness" of the traffic and I am just wondering if that is normal/expected for satellite service in general, and/or expected from Xplornet's service, or if what I am seeing is not expected at all (i.e. not an artifact of the satellite signal but rather a network management issue).
Here's iperf3 for 30 seconds sending data (i.e. upload speed):
[ ID] Interval Transfer Bitrate [ 5] 0.00-1.21 sec 12.9 KBytes 87.4 Kbits/sec [ 5] 1.21-2.00 sec 6.47 KBytes 67.2 Kbits/sec [ 5] 2.00-3.00 sec 22.0 KBytes 180 Kbits/sec [ 5] 3.00-4.00 sec 41.4 KBytes 339 Kbits/sec [ 5] 4.00-5.00 sec 41.4 KBytes 339 Kbits/sec [ 5] 5.00-6.00 sec 55.6 KBytes 456 Kbits/sec [ 5] 6.00-7.00 sec 69.9 KBytes 572 Kbits/sec [ 5] 7.00-8.00 sec 89.3 KBytes 731 Kbits/sec [ 5] 8.00-9.00 sec 120 KBytes 986 Kbits/sec [ 5] 9.00-10.00 sec 86.7 KBytes 710 Kbits/sec [ 5] 10.00-11.00 sec 133 KBytes 1.09 Mbits/sec [ 5] 11.00-12.00 sec 184 KBytes 1.51 Mbits/sec [ 5] 12.00-13.00 sec 186 KBytes 1.53 Mbits/sec [ 5] 13.00-14.00 sec 159 KBytes 1.30 Mbits/sec [ 5] 14.00-15.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 15.00-16.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 16.00-17.00 sec 93.2 KBytes 763 Kbits/sec [ 5] 17.00-18.00 sec 264 KBytes 2.16 Mbits/sec [ 5] 18.00-19.00 sec 124 KBytes 1.02 Mbits/sec [ 5] 19.00-20.00 sec 157 KBytes 1.28 Mbits/sec [ 5] 20.00-21.00 sec 120 KBytes 986 Kbits/sec [ 5] 21.00-22.00 sec 86.7 KBytes 710 Kbits/sec [ 5] 22.00-23.00 sec 369 KBytes 3.02 Mbits/sec [ 5] 23.00-24.00 sec 197 KBytes 1.61 Mbits/sec [ 5] 24.00-25.00 sec 90.6 KBytes 741 Kbits/sec [ 5] 25.00-26.00 sec 193 KBytes 1.58 Mbits/sec [ 5] 26.00-27.00 sec 192 KBytes 1.57 Mbits/sec [ 5] 27.00-28.00 sec 189 KBytes 1.55 Mbits/sec [ 5] 28.00-29.00 sec 193 KBytes 1.58 Mbits/sec [ 5] 29.00-30.00 sec 179 KBytes 1.46 Mbits/sec - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-32.20 sec 4.41 MBytes 1.15 Mbits/sec 388 sender [ 5] 0.00-30.00 sec 3.57 MBytes 998 Kbits/sec receiver
which averaged the overall prescribed "upload" speed, but notice that it's not 1Mb/s in any kind of a steady stream but rather bursts of higher than 1Mb/s speed followed by low/no speed. At one point it was 2 seconds with no transfer at all even.
and here's receiving (i.e. "download"):
[ ID] Interval Transfer Bitrate Retr Cwnd [ 5] 0.00-1.35 sec 46.6 KBytes 283 Kbits/sec 0 12.9 KBytes [ 5] 1.35-2.00 sec 0.00 Bytes 0.00 bits/sec 0 12.9 KBytes [ 5] 2.00-3.00 sec 67.3 KBytes 551 Kbits/sec 0 37.5 KBytes [ 5] 3.00-4.00 sec 46.6 KBytes 382 Kbits/sec 0 40.1 KBytes [ 5] 4.00-5.00 sec 105 KBytes 858 Kbits/sec 0 44.0 KBytes [ 5] 5.00-6.00 sec 88.0 KBytes 721 Kbits/sec 0 54.3 KBytes [ 5] 6.00-7.00 sec 141 KBytes 1.16 Mbits/sec 0 69.9 KBytes [ 5] 7.00-8.00 sec 124 KBytes 1.02 Mbits/sec 0 101 KBytes [ 5] 8.00-9.00 sec 186 KBytes 1.53 Mbits/sec 0 146 KBytes [ 5] 9.00-10.00 sec 248 KBytes 2.04 Mbits/sec 0 206 KBytes [ 5] 10.00-11.00 sec 311 KBytes 2.54 Mbits/sec 0 257 KBytes [ 5] 11.00-12.00 sec 0.00 Bytes 0.00 bits/sec 43 194 KBytes [ 5] 12.00-13.00 sec 0.00 Bytes 0.00 bits/sec 75 199 KBytes [ 5] 13.00-14.00 sec 435 KBytes 3.56 Mbits/sec 0 199 KBytes [ 5] 14.00-15.00 sec 0.00 Bytes 0.00 bits/sec 34 114 KBytes [ 5] 15.00-16.00 sec 0.00 Bytes 0.00 bits/sec 34 140 KBytes [ 5] 16.00-17.00 sec 373 KBytes 3.05 Mbits/sec 0 149 KBytes [ 5] 17.00-18.00 sec 0.00 Bytes 0.00 bits/sec 0 162 KBytes [ 5] 18.00-19.00 sec 373 KBytes 3.05 Mbits/sec 0 168 KBytes [ 5] 19.00-20.00 sec 0.00 Bytes 0.00 bits/sec 0 171 KBytes [ 5] 20.00-21.00 sec 373 KBytes 3.05 Mbits/sec 0 172 KBytes [ 5] 21.00-22.00 sec 0.00 Bytes 0.00 bits/sec 14 141 KBytes [ 5] 22.00-23.00 sec 0.00 Bytes 0.00 bits/sec 0 120 KBytes [ 5] 23.00-24.00 sec 373 KBytes 3.05 Mbits/sec 0 131 KBytes [ 5] 24.00-25.00 sec 0.00 Bytes 0.00 bits/sec 1 146 KBytes [ 5] 25.00-26.00 sec 0.00 Bytes 0.00 bits/sec 14 104 KBytes [ 5] 26.00-27.00 sec 0.00 Bytes 0.00 bits/sec 0 104 KBytes [ 5] 27.00-28.00 sec 373 KBytes 3.05 Mbits/sec 0 107 KBytes [ 5] 28.00-29.00 sec 0.00 Bytes 0.00 bits/sec 0 119 KBytes [ 5] 29.00-30.00 sec 373 KBytes 3.05 Mbits/sec 0 123 KBytes - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-30.00 sec 3.94 MBytes 1.10 Mbits/sec 215 sender [ 5] 0.00-30.80 sec 3.13 MBytes 853 Kbits/sec receiver
Again, very bursty with periods of 1-2 seconds with no transfer.
As you can imagine, the bursiness of this makes for horrible video conferencing since that cannot "buffer" the way single-direction streams like streaming video can and the codec ends up using the "worst case" dips as the speed of the connection and encodes for that.
Cheers, b.