TDMA is a good point. If the subscriber radio has to send a bandwidth request and await a reply with an assigned slot in the next frame before it can send actual data, it would add an extra ~240 ms.
On Fri, Aug 3, 2018 at 12:05 PM Colin Stanners <cstann...@gmail.com> wrote: > Subscriber uplink is likely using some sort of TDMA - those protocols are > very difficult to keep efficient when you have hundreds of users in a > channel, weather considerations, priority classes and 240ms latency from > all clients to the headend. Adding 20-200ms for that is probably > reasonable. Also you probably can't internally route on the network to go > to the backbone link closest to the desired internet host - likely > everything comes out of one satellite uplink location that adds its own > latency to hosts that are located on the other side of the country. > > On Fri, Aug 3, 2018 at 10:28 AM, <ch...@wbmfg.com> wrote: > >> Lesseeee 22,400 x 2 /186000= 240 mS one way. >> So 480 mS ping RT under perfect conditions. >> >> But in real life it is twice that. No idea why. Perhaps they are using >> another satellite connection for backbone feed. >> >> *From:* castarritt >> *Sent:* Friday, August 3, 2018 9:22 AM >> *To:* af@af.afmug.com >> *Subject:* Re: [AFMUG] Satellite internet stats >> >> It is the ~23,000mi orbit geostationary birds that kill latency. When a >> ping to a terrestrial server has to travel >90,000mi, the latency will >> never be better than half a second. Musk wants to do a large constellation >> of low orbit birds. >> >> >> On Fri, Aug 3, 2018 at 10:18 AM Seth Mattinen <se...@rollernet.us> wrote: >> >>> On 8/3/18 8:03 AM, Bill Prince wrote: >>> > Latency still sucks. 700-800 ms if there is no congestion. >>> Multi-second >>> > latency if there is congestion. >>> > >>> >>> >>> Time for some quantum entanglement. >>> >>> -- >>> AF mailing list >>> AF@af.afmug.com >>> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >>> >> ------------------------------ >> -- >> AF mailing list >> AF@af.afmug.com >> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >> >> >> -- >> AF mailing list >> AF@af.afmug.com >> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >> >> > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com >
-- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
