| reply to funchords
Re: our competitive market said by funchords:#1 is true for the TV side as well. The content comes from somewhere, and although we might have to make one step down away from the 3rd-part aggregation point in order to make my comparison, there are one-time and ongoing costs for interconnecting these things even within the same metro area. #2 -- to RF, really? It's not sent to my box digitally and converted into RF there? #3 and this is really the rough comparison I'm making -- both systems are (roughly) similarly subject to usage saturation. But we're making "hogs" out of the users who don't watch Comcast video products. #1 If you are refering to the costs for the content, that's where your TV rates go. Depending upon the size of the MSO, your interconnect fees (to get the content) could be handled at the system level, the region level, division, or corporate. It all depends where they stick the dish. The ongoing fees are the XX amount per subscriber fees that your tv rates go to pay.
#2 As others already pointed out, It's sent via QAM digitally, but QAM works different from DOCSIS for your data.
#3 The big differences "last mile" between your VOD and data is the way the system reacts. With VOD if the capacity is maxed you just get an error that basically says "No available resources" (channels) when trying to set up the actual video session. Beyond that, what other people are watching on their VOD stream isn't going to effect your VOD stream's performance. The actual QAM can't/won't let any streams be created to max it's available output bandwidth. In theory, it's also a bit easier to add capacity on the RF side because you could throw an extra QAM anyplace you have the available bandwitdth on the plant.
With a cable modem, things work differently. First off, pretty much everybody is talking at the same time. Your 2 places to control the speed are at the modem itself (what it's provisioned/capped at), and at the CMTS node equiptment. Unlike a video stream with will take the available bandwidth and basically reserve X amount of bandwith for the stream and is the only thing broadcasting on that frequency, with a cable modem you have many different devices broadcasting basically sharing the big pipe. What your neighbor is doing, can actually effect your performance. (say your neighbor uncaps his cable modem so it no longer has the speed governor that the provisioning caps are there for). It's actually possible in theory to bring everybody's feed to a standstill if you have too many devices trying to talk at once or have a couple uncapped modems just shotgunning out data without respect for the "rules of the road" and sharing the connection. (I believe modems may use a time-sharing mechanism like settop boxes do to help avoid overtalk..but I'm not certain). On top of that, it's not as easy to add capacity. Cable-modems' tuners don't have the frequency range that a video settop box has. this limits the available RF space you can stick the downstream. their transmitters are also limited in their frequency range. So this means to just plug in additional capacity, you may have to do a lot of shuffling of services on the RF...and that becomes a pain in the ass when you factor in FCC rules on notification. The other, more widely used route is to do a node split. Basically, you split the areas on the plant being fed by the CMTS at the node so you can basically create a new node. This requires physical work because you need the new equiptment for the node, plus you need to do some rewireing work to basically cut the existing node in half RF wise so you don't end up with cross-talk and end up breaking everything.
Once nice thing with DOCSIS 3 coming up is the fact that thru the channel bonding it makes it easier to enlarge the pipe. Everybody looks at it as a way to increase their upload/download speeds, but if you think about the way everybody shares the existing pipe, If you enlarge that pipe but keep the existing speed caps, you are still going to get an effective speed increase during those peak times. Even though it probably won't happened because of marketting, currently during peak times EVERYBODY may slow down a bit..or a lot... if you increase the size of the pipe, more data can get thru allowing everybody to stay at their top speeds even during those peak times.
Think of it like highway traffic. We've all been in situations where they close a lane or something and traffic slows dramatically for everybody. We may have quick bursts up to a high speed, but we can't average anywhere near the speed limit. Then suddenly a lane opens back up, and the traffic spreads out and increases speed. Even if we aren't going above the speed limit like we may do during those off-peak times on the road, we are going much closer to the speedlimit and ultimately are averaging a higher speed than we were before just because there is more capacity.
Make sense? |
