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Technology Stocks : The *NEW* Frank Coluccio Technology Forum -- Ignore unavailable to you. Want to Upgrade?

To: justone who wrote (907)	9/29/2000 9:54:38 PM
From: Frank A. Coluccio	Respond to of 46821

justone, while many of your observations are IMO pointed in the right direction, keep in mind that these folks, like Tachyon, are providing links to/from wireless hubs. This is a different scheme, with a different transmission transaction profile, than direct satellite to the home. When there is an ISP providing hubbing, then there is also an increased probability that some portion of the traffic coming from local providers traversing those hubs will remain local to the ISP's autonomous network (i.e., within their border). And as relates to the uplink, there are also statistical possibilities for improved efficiencies through statistically stacking multiple users instead of encountering idle times (and there is also the increased potential for periods of heightened congestion, as well) that are not experienced with direct links from the bird to the home, when comparing hubbed vs. direct. Of course, those backbone related occurrences could also take place on terrestrial lines (upstream T1/T3 links to the core), as well. When terrestrial hubbing is employed, with the uplink serving only as the aggregation pipe, the domain of contention is "shifted" from the bird's backbone to the local hubmeister. I believe that it is a more efficient approach for the following reason: Ack-nak turnaround times to and from the bird are for many sessions eliminated when they are local, or greatly reduced, in the case where a local hub is doing traffic cop. Whether this type of architecture makes sense or not really depends on the ways local ISPs deploy it in rural and stranded areas. If they can gain access to the Internet's core more efficiently via satellite than they can by buying very expensive Fractional T3 (F/T3) transit to a national backbone and NAP (and the latter is actually the real selling point for those ISPs), then I'd say that it has merit. But in dense urban areas where T1s and T3s are now being sold like popcorn, I'd have to wonder about just what it is that would incent an ISP to take this route. In the case of Tachyon (who does not seem to be making a lot of noise over this, I might add), it appeared to make sense to me from what I read in the Cook Report, based on what I inferred from prospective ISPs who planned to use their upstream services. Go to the tachyon.net site and click on partners. These are two of Tachyon's "partners:" discover-net.net aplus.net I don't know enough about TeleCrossings, though. I remain cautious, as you can see, to express judgement about their claims. Let's see if they deliver, and where. BTW, when I saw them frontrunning the claim of supporting NY in a way that now seems almost obligatory, I had to wonder. The first thing I thought about was early spectrum exhaust. Let's wait and see. FAC

To: justone who wrote (907)	10/1/2000 10:19:30 PM
From: Ilaine	Read Replies (1) \| Respond to of 46821

There's at least one erroneous assumption in your back of the envelope calculation - Alphastar/Telecrossing isn't launching birds, they are leasing space on a bird someone else already launched. geamericom.com geamericom.com I believe your assumptions as to bandwidth/capacity are also erroneous, but not being an engineer, I can't explain why. GE-5 has 16 transponders, each with a 54 MHz capacity, but I have no idea what sort of data throughput that means. I think in light of the fact that we are talking about radio waves, photons, the transmission rate is greater than what goes over copper, electrons. It certainly has a greater potential speed than any other technology, 50 Mbps to 48 Gbps. andrew.cmu.edu The author of this website is expert on the issue of TCP/IP via satellite, he suggests using "multiple narrow TCP pipes," whatever that is. ee.surrey.ac.uk

To: justone who wrote (907)	10/17/2000 8:11:57 AM
From: Valueman	Read Replies (2) \| Respond to of 46821

I can't believe I missed a good satellite internet discussion! - say @4.4 Kpbs real continuous data demand per active user (this is the total demand for the user averaged over the web session) - these users share 44 mbps as quoted in the press release - peak demand is one active user per 5 subscribers This means one satellite can handle ~50,000 subscribers. Each 36 MHz transponder has about a 45 Mbps capacity. A service like Gilat's Starband is starting off with 14 transponders on Loral's Telstar 7 satellite. A typical sat today has approximately 24 Ku-band, and 24 C-band transponders. FYI, in Starband's S-1 filing, they have been getting 7,500 subs per transponder while maintaining their 150 Kbps minimum. To wrap up this summary, a sat costs ~$250 million to build, launch, and insure. Other fun facts--a typical modern sat has about 1.2 Gbps throughput capacity. Birds being built now, with frequency reusing spot beams, will up that to 6-7 Gbps. Technology of ViaSat can be used to boost that capacity to 20-40 Gbps on a Ka-band spot beam satellite.