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To: Frank A. Coluccio who wrote (9321)	11/26/2000 4:38:08 PM
From: ftth	Respond to of 12823

In general I'd think 100Mb Ethernet is about all the coax will comfortably support without some additional whiz-bang DSP restoration techniques added to the mix. GbE--maybe--in some cases where they have retrofitted RG-11 for the whole path, including inside the home. But the RG-59 in most homes won't cut it. I'm just speculating on these things--haven't ever tried sending GbE down 2000 feet of RG59 myself so if anyone either knows differently, or can confirm this, please speak up Changing the Ethernet PHY to high order QAM for support of multigigabit streams is a different proprietary undertaking, but maybe one that some will pursue. Maybe DOCSIS 5.0?<ggg>. I think you'd be hard pressed to make it cost effective at present due to--at the very least--the A/D cost, if you're talking much above 16QAM or so. But hey, who knows what the future holds. But you may be right, and I could definitely forsee people exploring this path due to "fear of fiber."

To: Frank A. Coluccio who wrote (9321)	11/28/2000 9:00:41 PM
From: DenverTechie	Read Replies (1) \| Respond to of 12823

Frank, unfortunately I haven't been following this train of thought closely on the thread, so I'll just throw out some random thoughts on the matter of digital baseband in cable plant. A pure digital baseband cable network has been considered nirvana by the industry for quite some time. The problem being one of history, of which I'm sure you are quite aware, and the evolution has been fairly slow to embrace digital formats of any kind. Since all content format from the inception of cable has been in analog format, when fiber was introduced, and hence the HFC concept, there were 2 driving forces in place to determine what architecture would be in place. The first was that everything was in analog format since it was all video entertainment. They looked at going to digital lasers as the phone companies had (where everything is digitized, but in 4 kHz chunks, not 6 MHz channels) and the cost to digitize that bandwidth at the time was prohibitive. So along came a company that demonstrated analog lasers and now the MSO could just reuse its existing modulators to go downstream. So today everything is analog fiber and all digital services are modulated to QPSK or QAM or OFDM (even FSK in some cases dare I say). But that does not get away from the basic ANALOG nature of the cable plant whether it be 550 MHz, 750 MHz, or 1 GHz. It's all still analog bandwidth, with digital modulation placed on that analog carrier. It's changing the carrier where the answer lies. The second major factor in place when HFC became viable was that of economics. Payback periods, cash flow (swimming pools, movie stars). Cost factors at MSOs reign supreme. Can the MSO go to baseband digital carriers? The technical answer to that is yes. The economic answer is probably not for a while. Several innovative suppliers are dipping their proverbial toe in the water. Scientific-Atlanta actually has a transmission system that incorporates a pure digital baseband return path (upstream). And it is cost effective. It is difficult to implement due to legacy applications that want to modulate their digital signals into QPSK or QAM (cable telephony or CM data). It's almost a chicken and egg thing. Once the baseband digital is in place, they can use pure digital signals for transport. In the meantime, they can't and use QPSK or QAM. Until they stop using QPSK or QAM, the operators won't go to baseband digital! Downstream is tremendously more legacy driven, where whole headends would have to be turned upside down to convert to baseband digital. When provided with the inevitable bandwidth exhaustion question, the standard response is that digitizing the channels, while maintaining the analog carrier, will yield sufficient bandwidth gains to the foreseeable future (at least 3 high quality digital video channels replaces 1 analog 6 MHz channel). And then there is always node splitting, which actually doubles the available bandwidth in a neighborhood each time the node is split into smaller and smaller "pies". But, as has been suggested in these spaces, true baseband digital service on cable is an attractive possibility that is under development by most major cable suppliers now due to the overwhelming trend in the industry to digitize everything and place integrated services on IP based networks. We now have the paradox that the additional expense of doing the additional digital modulation of QAM or QPSK to place these services on an analog carrier is getting restrictive. We'll soon have all digital voice, video and data running over the legacy analog carriers due to architectures planned and designed when there was nothing more than one-way video entertainment to consider. And the architecture of cable plant today is still designed and engineered to optimize that analog video service. The advances that we've seen in recent years that incorporate SONET transport rings and metro-DWDM narrowcast systems are a reaction to the proliferation of advanced digitally based services that demand more than the original analog laser carrier systems could handle. So is the dream of a pure digital baseband cable network possible? Absolutely. Just keep in mind that industry drivers when you contemplate when such a system could be implemented. PS - as you can see, I've got a few spare minutes these days, don't know how long it will last. I've been enjoying some breathing space. Exciting and hectic these days what with cable telephony booming and the transition to IP telephony on cable networks just now coming to fruition. Some I'm caught between 2 worlds, having to serve both. The talent pool in the industry that knows both circuit switched cable telephony and IP based cable telephony is virtually nonexistent, so guess who they come to? DT

To: Frank A. Coluccio who wrote (9321)	12/3/2000 10:44:42 AM
From: MikeM54321	Read Replies (3) \| Respond to of 12823

Re: Can HFC Plant Deliver DEDICATED 40mb/s? Frank, ftth, DT, and/or justone- This is getting confusing. So pardon my questions if they are also confusing. I think this is related to the post I just did regarding WINfirst. So is the system being proposed below to deliver dedicated 40mb/s connections unreasonable because of the same reason WINfirst is going to be building a parallel HFC plant over their greenfield FTTH plant? Frank- Does the following article parallel your thinking about turning the HFC plant into a pure digital baseband format? If so, then DT's reply about cable TV being inherently analog based, would seem to make the following proposal unreasonable. Am I understanding this correctly? Thanks. -MikeM(From Florida) ________________________ Cable technology to offer dedicated 40M bit/sec By MICHAEL MARTIN Network World, 11/20/00 AUSTIN, TEXAS - Everest Connections, a St. Louis communications provider, is planning trials of a cable technology capable of offering 40M bit/sec at DSL and cable modem prices. The trials will begin next year in the Kansas City, Mo., area. Known as Ultraband, the technology was developed by Advent Networks in Austin, Texas, and runs over hybrid fiber coaxial networks. Unlike cable modems, which must share bandwidth with other cable modems attached to a certain cable branch, Ultraband uses switched Ethernet over cable, creating virtual channels for each user, so users gets guaranteed performance. "The existing cable modem technology is fine for basic data and e-mail," says Geoffrey Tudor, Advent's CEO. "We're going to allow more revenue-intensive services that would let service providers make a profit." Because Advent is offering dedicated bandwidth sets Ultraband apart from traditional cable modem technology, says Adam Guglielmo, an analyst with consultancy TeleChoice."Basically, everyone will have a VPN on the network," he says. The speeds Advent is offering may seem like a lot, Guglielmo says, but he expects that over the next year users will demand more bandwidth. "It's probably a little ways out before there's big demand for this kind of bandwidth," he says. "But I think Advent would say they're building this for networks of the future." Everest is slated to begin offering Ultraband services in 2001. Ultraband will be available to other service providers in the second half of 2001, Tudor says. Applications businesses might run over Ultraband include video and packet telephony, Tudor says. With the bandwidth Ultraband serves, Tudor thinks IT outsourcing firms could use the technology to link clients back to a central site, where the outsourcer could perform tasks such as remote storage-area network backup. While providers will roll out Ultraband as a residential service, Tudor says the technology will appeal to small and midsize businesses that can't afford a T-1. Because Ultraband uses the same basic infrastructure as broadband cable service and also requires a modemlike box on the customer site, its cost should be comparable to cable modem or DSL service, Tudor says. nwfusion.com