Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

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

To: ftth who wrote (491)	7/22/2000 1:07:35 AM
From: Frank A. Coluccio	Respond to of 46821

ftth, I assume you meant "upstream" You didn't heed my qualifier when I stated: even though there may be arbitration tricks taking place ..." The PDAMA that you alluded to is the trick that I alluded to. But I chose not to go there because (i) I am not well versed in it, and (ii) it would have been only one of three or four schemes, hence, an incomplete treatment. I spoke in generalities, taking license to assign the blame to the network region that imposes the constraint. The access portion. Even if the remedy is somewhere else. You are technically correct, and correct from a semantic standpoint, but the causality here stems from the constraint of the 6 MHz channel, or over the access pipe (that section between the operator's head end and the End User. So, in common everyday terms I called this quality "contention," even if it is misplaced by a couple of coaxial connections in the next rack. We further simplify matters when using shortspeak in mixed company by saying its in the access portion, even though it's not on the pipe itself, where the RF Channel imposes the constraint. By the time the data arrives over the pipe it's already been back-pressured and treated. Thanks for the expansion.

To: ftth who wrote (491)	7/22/2000 8:50:11 AM
From: MikeM54321	Read Replies (1) \| Respond to of 46821

"First, I assume you meant "upstream" since there is no contention in the downstream. It is scheduled, but there is no access contention." ftth and Frank- Bear with me, because I'm barely able to comprehend your current discussion with Frank. So I may not be wording my question just right. But here goes. When you say, "no contention in the downstream," were you assuming that the model I theoretically proposed upstream(HUGE bandwidth direct to the STB via a specially dedicated 6mhz channel), is in effect? Maybe a better way to put it is, if the MSO gives us a current cable channel of 6mhz, and uses it to allow us to go out and choose content from the 500 million or so websites out there in WWW land, would that cause a huge downstream contention issue? Basically I'm trying to figure out if the current, state of the art 750mhz cable plant, can indeed give us a big fat downstream WWW pipe, delivered right to couch potatoes for their viewing pleasure. Thanks. -MikeM(From Florida)

To: ftth who wrote (491)	7/22/2000 9:27:23 PM
From: Frank A. Coluccio	Read Replies (1) \| Respond to of 46821

ftth, [and thread] I've gone over your [uplinked] message and I see that we're (maybe it's just that I am) all over the map, partly due to jumping from the interactive stb discussion between here and LMT, and the DOCSIS cable modem topic. [Mike, you are not the only one who is now confused. smile ] I agree with your point in your PM that we need to take a moment to level-set and establish some common terminology before we take this further. I would advise anyone who has an interest in this topic to disregard my previous responses to ftth's last post, since I apparently misunderstood what he was referring to by PDAMA and prematurely proceeded to comment on it. I don't have a handle on the specifics of this protocol other than a general understanding of the principles involved, namely, windowing [which you called scheduling, same thing], or the allocation of time slots, which is dependent on the number of other users on line, for the transmission of upstream data. I'd like to re-state that we are talking about DOCSIS Cable Modem operation, not interactive set top box flows, for now, and that we should focus on both the upstream and downstream dynamics, one at a time. I think that's a good start. What say? By the way, I did a couple of searches on PDAMA in hotbot and lycos, and the closest thing I got was a reference from 1995 of a modified PDAMA used in satellite systems. The other hit was for some pharmaceutical act passed by congress. If you have a paper to point to during your reply, it would be much appreciated. Likewise, I have several recent vintage residential broadband technology texts which make reference to DOCSIS in some detail but do not mention this protocol, although they do describe in rather over-generalized terms what it does. So, ftth, please take over from here, since yours is a far better understanding, using more precise and up-to-date terminology, than mine. If you would, describe the PDAMA dynamics in the upstream direction in more detail, and while you are at it give us a refresher on what takes place in the downstream operation again, as well, citing DOCSIS 1.0 and 1.1 approaches, if there are any differences between the two. TIA. FAC