xplornet contact or any experience with their satellite service?

Tue Apr 21 18:11:05 UTC 2020

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 at 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.