Re: Latency, TCP ACKs and upload needs

On 20/04/16 16:27, Leo Bicknell wrote: 90%+ of the stacks deployed will be too small. Modern Unix generally has "autotuning" TCP stacks, but I don't think Windows or OS X has those features yet (but I'd be very happy to be wrong on that point). Regardless of satellite uplink/downlink speeds,

Re: Latency, TCP ACKs and upload needs

Wed, Apr 20, 2016 at 07:27:53AM -0700, Leo Bicknell wrote: > 90%+ of the stacks deployed will be too small. Modern Unix generally > has "autotuning" TCP stacks, but I don't think Windows or OS X has > those features yet OS X since ~10.5 has autotuning, here are some hints from ESnet

Re: Latency, TCP ACKs and upload needs

Leo Bicknell wrote: > > 1460 byte payloads down, maybe 64 byte acks on the return, and with SACK > which is widely deployed an ACK every 2-4 packets. You would see about > 2,140 packets/sec downstream (25Mbps/1460), and perhaps send 1070 ACKs > back upstream, at 64 bytes each,

Re: Latency, TCP ACKs and upload needs

On Tue, 19 Apr 2016, Jean-Francois Mezei wrote: Considering a single download TCP connection. I am aware that modern TCP stacks will rationalize ACKs and send 1 ACK for every x packets received, thus reducing upload bandwidth requirements. Is this basically widespread and assumed that

Re: Latency, TCP ACKs and upload needs

On 4/20/16, Leo Bicknell wrote: > > Others have already answered with the technical details. Let me take a > stab at some more, uh, variable items. [.. snip lots ..] > 90%+ of the stacks deployed will be too small. Modern Unix generally > has "autotuning" TCP stacks, but I don't think

Re: Latency, TCP ACKs and upload needs

Thanks to all for the sanity check. Always depressing when you think you may have a good argument but after much reading, you find out you don't :-( BTW, in case someone knows. With the recent "beam" satellites having a lot of different focused antennas, how does the uplink work ? Does all

Re: Latency, TCP ACKs and upload needs

On 4/19/16, Jean-Francois Mezei wrote: > As part of the ongoing CRTC hearings, the incumbents' claim that > continued implementation of the current 5/1 standard would make Canada a > world leader for broadband in the future. > > A satellite company who currently can't

Re: Latency, TCP ACKs and upload needs

Others have already answered with the technical details. Let me take a stab at some more, uh, variable items. In a message written on Tue, Apr 19, 2016 at 09:29:12PM -0400, Jean-Francois Mezei wrote: > Also, when you establish a TCP connection, do most stacks have a default > window size that

Re: Latency, TCP ACKs and upload needs

a geostationary orbit based connection will have a minimum latency of 492-495ms in a dedicated-carrier configuration between two earth stations, varying very slightly with the modem overhead time for FEC. In a TDMA network all bets are off, if you're in wyoming on exede and everyone is asleep,

Re: Latency, TCP ACKs and upload needs

On 4/19/16 6:29 PM, Jean-Francois Mezei wrote: > As part of the ongoing CRTC hearings, the incumbents' claim that > continued implementation of the current 5/1 standard would make Canada a > world leader for broadband in the future. > > A satellite company who currently can't even deliver its

Re: Latency, TCP ACKs and upload needs

One of the things to consider is that geostationary satellite operators operate based entirely on the economics of oversubscription. If you were to purchase a full duplex 1 Mbps x 1 Mbps connection via VSAT terminal in North America (whether C, Ku or Ka-band) you'd be looking at $2000/month or

Re: Latency, TCP ACKs and upload needs

> On Apr 19, 2016, at 9:29 PM, Jean-Francois Mezei > wrote: > > As part of the ongoing CRTC hearings, the incumbents' claim that > continued implementation of the current 5/1 standard would make Canada a > world leader for broadband in the future. > > A satellite

Latency, TCP ACKs and upload needs

As part of the ongoing CRTC hearings, the incumbents' claim that continued implementation of the current 5/1 standard would make Canada a world leader for broadband in the future. A satellite company who currently can't even deliver its advertised 5/1 now brags its next satellite will deliver