 thender2Glamour ProfessionPremium
join:2004-05-16
Staten Island, NY | reply to Kfedka
Re: Not enough bandwidth? A 1080i channel with equal quality to OTA tv is 17 mbps.
This is real quality - not directv, overcompressed-because-satelite-bandwidth-sucks bandwidth.
Three TVs is 51 mbps.. that's a lot. Cable can't handle this at peak hours. Looking at all the prior posts in the front page news, most major cable ISPs can't even handle internet, much less more HDTV.
I forsee a day where your TV shows "you have exceeded your monthly limit as specified by the fair use portion of the TOS" instead of 24 at 9 PM on Monday night.
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The Problem With Music.
Our Rationale
Time to rewrite the DMCA. |
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| Cable is multicast not point to point like IPTV. It's not three people watching the same channel that causes the bandwidth usage, it's three people watching different channels that causes it. With SDV the slots are allocated as people ask for the channel.
I actually see SDV as a pretty good solution. It eliminates 50% of the bandwidth waste. Combine that with DOCSIS 3.0 providing more bandwith and ultimatly putting less people on a node and I think cable has bandwidth for years to come. The question is: are those things cost competive compared to just going pure fiber. |
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| reply to thender2
said by thender2:A 1080i channel with equal quality to OTA tv is 17 mbps. This is real quality - not directv, over compressed-because-satelite-bandwidth-sucks bandwidth. Three TVs is 51 mbps.. that's a lot. Cable can't handle this at peak hours. Looking at all the prior posts in the front page news, most major cable ISPs can't even handle internet, much less more HDTV. I forsee a day where your TV shows "you have exceeded your monthly limit as specified by the fair use portion of the TOS" instead of 24 at 9 PM on Monday night. 1080i signal = 19.1 mbits, 720p signal = 15.3 mbits. Each Analog channel takes 6 MHz of freq, most cable networks in the US are 550 MHz, 750 MHz or 960 MHz. You can fit 6-8 digital channel or 2 HD channel in the same spot as 1 analog channel… I believe with QAM256 you are able to get 38.1 mbits per 6 mhz…
SDV will work the same way that current cable system works on the stand point on the node it doesn’t matter if 1 person or a 100 are watching. What SDV does is allocate frequencies to certain channels dynamically, much like DHCP work for a cable modem or your home network. So for instance let’s say I'm the first person to watch DiscoveryHD in my neighborhood, you tune to the channel on your cable box, the box sends out a signal to the node saying I want to watch discoveryhd. It checks to make sure I pay for the channel, and then allocates a frequency to that channel. Now let’s say Fred, 8 house down, also wants to watch discoveryhd at the same time as I am watching it. He tune to the channel on the cable box, the box sends out a signal to the node saying I want to watch discoveryhd. It checks to make sure I pay for the channel, and then sees that someone else is watching it on the node and what frequency is allocated to that channel on the node, it then uses the same frequency and tunes in without using anymore bandwidth. So doesn’t matter if 1 or 100 are watching it, or if you have the same channel on 10 TVs in your house. |
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thender2Glamour ProfessionPremium
join:2004-05-16
Staten Island, NY | Thanks, that was pretty interesting. I like learning new stuff on here. |
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mobbo
join:2005-04-13
Denton, TX | reply to valuepac0
Very nice explanation! So if this is true, it would actually be good if on one node 1,000 people were watching "24" or the Super Bowl because, essentially, it would only be like allocating a frequency for 1 person? |
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| reply to valuepac0
So the problem really is the current situation where you have digital and analog being delivered over the same cable? From what you posted it seems to me this problem self corrects if the digital switchover takes place in February 2009 as currently scheduled. |
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