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ViaSat Delivers 12 Mbps+ Via Satellite
An anonymous reader writes "Last Thursday, ViaSat announced pricing for its new home broadband service, which is set to deliver 12 Mbps+ download speeds (3 Mbps+ up) beginning next week for $50 per month. Engadget just dropped by the company's demo home just a few feet from the Engadget trailer at the Las Vegas Convention Center parking lot to try it out, and posted their review." The comments there, understandably, wail for information about how much data that $50 buys.
Caps can be an issue, but if you are rural these speeds and prices are an instant upgrade.
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The thing people miss about satellite connections is that they are never anywhere near 100%. 98% of your packets getting through sounds good in theory, but in practice it makes most TCP based protocols painful. You won't be doing much realtime anything over satellite. Mind you, i've lived at the end of multiple satellite links that I managed in SWA. We had great conditions - flat terrain, few clouds, no smog, high elevations due to being relatively close to the equator. You still lose a few here and there. It slows down downloads, causes losses even from IM traffic, emails fail to send, you name it.
A well managed and accelerated 12mbps downlink could provide some excellent speed, comparable to a high end DSL link. The real numbers you'll see will hover in the 700k/sec range in raw download speed. The latency is never going to be better than 520ms and probably worse, depending on the ground station location.
The problem with this technology is that it's Ka based. Ka is much worse in regards rain fade than Ku itself, which made the concept famous. All Ka systems I have worked with (commercial, and military) can't hit the bird anymore when the sky gets cloudy or a few drops of rain hit ground. This doesn't sound like a winner.
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What's the total bandwidth of the satellite? If you can get 12Mbps when nobody else is using it, that sounds great until they have about 5 customers.
140 Gbps/1 satellite - approx 12000 users downloading at full capacity in the same time.
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Acceleration is the key there. When I was Network Guy(tm) for a satellite provider, we could easily push 15-20Mbps of a single stream of TCP traffic over the bird using TurboIP boxes from Comtech/EFData. It did tricks with TCP windows and ACKs that let you overcome TCP slowstart.
And I don't understand the whole "OMG 520ms latency kills VOIP!" argument. We had hundreds of Cisco IP phones out at the end of our VSAT links and nobody complained one bit about it. It takes about 15 seconds for your brain to realize "Oh, there's a bit of lag" and adjust. i think people are complaining about jittery connections that have latencies that bounce around between 520ms and 3000ms because of how you're sharing both the uplink and downlink channels with everyone else. Our systems could detect SIP calls and switch you from a shared channel to a dedicated channel big enough to handle your call + additional overhead.
I understand the thrust of your opinion here, but wanted to clarify regarding your dismissive statement, "And if junior has a sister, she's going to be rooting for the Netflix too" -- a 2004 survey by the Entertainment Software Assoc. had females comprising 25% of console gamers and 39% of PC gamers.
As a Wildblue subscriber on the highest teer package, who gets slowed down to dialup speed a couple times a year for using more then 17 gigs in a month (yes that is the current highest residential cap) I've been following this story pretty close. There are a few facts that are definetly getting downplayed so far both here and in the Engadget piece. For one Viasat isn't just partnering with Wildblue, they now own them, or at least a pretty big share. And they have been talking this kind of speed since Viasat 1 was still in design, so even though it's great to see it in practice, that is nothing new. And most blatantly absent is the caps themselves. From all reports (not publicly confirmed, but much evidence to back up) the $50 package that he mentions will only be for 7.5 gigs combined down and up. The next level is 15 gigs combined down and up for $80, and the top tier is 25 gigs combined for $130. And after that it's $10 a gig, or a significant slow down, like they have now.
You can find discussion about this on Wildblue's own forum http://wildblueworld.com/forum/
Like I mentioned earlier, Viasat has been talking this up as a real competitor to DSL for quite some time, so many of us existing customers hoped (assumed) that that meant they would give us some realistic caps to go along with the speed, but it appears that is not the case. So although the speed bump is cool, remember that at the lowest level, 1 Netflix movie along with normal browsing will probably put you over for the whole month.
I don't think the geostationary distance is responsible for the latency
Err, do a calculation before saying stuff like this..
geostationary orbit is about 40,000km from surface of US, more or less. Speed of light is 300,000km/s. So ping due to speed of light limitation is 40*4/300 = 533ms. Remember, packet has to go from base station to sat to your residence then ACK has to go from your residence to sat to base station.
Now add another 100+ms for you equipment latency and base station, and you have in excess of 650ms. And that's not accounting for even errors in trasmission.
So yes, geostationary distance is most of the latency issue.