Joe12345678
join:2003-07-22
Des Plaines, IL
| How much space does SDV free up in a high use area?
How much space does SDV free up in a high use area?
At what point is the SDV split done the headend? the node?
What happens when there is not room left channels that are need in a area?
Things like that may end of stopping cable from having 200+ hd channels?
Will all channels be on SDV or will some high use ones be on all the time? |
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MacLeech
The one and only
Premium
join:2001-07-14
SoCal
3 edits | said by Joe12345678  :How much space does SDV free up in a high use area? Depends...
said by Joe12345678 :At what point is the SDV split done the headend? the node? Headend. It's where the data transport ends and the distribution begins anyway. It's the choke point where the cable company has to decide and generate what to send down the smallest pipe in their network. It's where the RF channels are created.
said by Joe12345678 :What happens when there is not room left channels that are need in a area? Customers and server logs get an error message. Network management should be monitoring such events for repair or upgrades.
said by Joe12345678 :Things like that may end of stopping cable from having 200+ hd channels? Why? It's possible they could also just go IPTV and send just the channel requested. Without SDV or IPTV, they can't even get to 200+ HD channels because of all the other channels demanding RF spectrum.
said by Joe12345678 :Will all channels be on SDV or will some high use ones be on all the time? Only the channels the provider setup are on SDV, it doesn't have to be all of them. It could be a handful. It could just be the PEG (public, education, and government) channnels they're mandated to carry but everybody claims never to watch... or it could be shopping channels or Hallmark and Wealth in a college area or G4, Playboy, and SciFi in a senior citizen home. It really just depends on demand. |
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travelguy
join:1999-09-03
Santa Fe, NM
| reply to Joe12345678
said by Joe12345678 :How much space does SDV free up in a high use area? Depends on the engineering. In a non-switched system, every possible channel is transmitted to every house. That's what, 100 or two hundred channels?
said by Joe12345678 :At what point is the SDV split done the headend? the node? Wouldn't make sense to do it at the headend. Presumably it's done where ever the system transitions from fiber to coax.
said by Joe12345678 :What happens when there is not room left channels that are need in a area? Things like that may end of stopping cable from having 200+ hd channels? You don't need a separate channel for each house, just each channel being watched. Clearly they've done the analysis that shows that subscribers on a given node are unlikely to exceed the bandwidth available.
Anyway, SDV is just an interim step until they install fiber to the neighborhood or house.
said by Joe12345678 :Will all channels be on SDV or will some high use ones be on all the time? What purpose would it serve to be broadcasting a channel noone is watching? |
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fiberguy
My views are my own.
Premium
join:2005-05-20
| reply to Joe12345678
With the amount of Digital Channels that are used in a node at any given time, I'm almost certain that you won't saturate the node. I believe it was about, what, 20 channels per node in use at any-one time? Or was it 20%. Either way, the digital tier is used so little as compared to analog it's not a problem. |
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Joe12345678
join:2003-07-22
Des Plaines, IL
| reply to MacLeech
said by MacLeech :said by Joe12345678 :How much space does SDV free up in a high use area? Depends... said by Joe12345678 :At what point is the SDV split done the headend? the node? Headend. It's where the data transport ends and the distribution begins anyway. It's the choke point where the cable company has to decide and generate what to send down the smallest pipe in their network. It's where the RF channels are created. said by Joe12345678 :What happens when there is not room left channels that are need in a area? Customers and server logs get an error message. Network management should be monitoring such events for repair or upgrades. said by Joe12345678 :Things like that may end of stopping cable from having 200+ hd channels? Why? It's possible they could also just go IPTV and send just the channel requested. Without SDV or IPTV, they can't even get to 200+ HD channels because of all the other channels demanding RF spectrum. said by Joe12345678 :Will all channels be on SDV or will some high use ones be on all the time? Only the channels the provider setup are on SDV, it doesn't have to be all of them. It could be a handful. It could just be the PEG (public, education, and government) channnels they're mandated to carry but everybody claims never to watch... or it could be shopping channels or Hallmark and Wealth in a college area or G4, Playboy, and SciFi in a senior citizen home. It really just depends on demand. Playboy costs $14+ and up so that may end on SDV |
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Joe12345678
join:2003-07-22
Des Plaines, IL
| reply to fiberguy
said by fiberguy :With the amount of Digital Channels that are used in a node at any given time, I'm almost certain that you won't saturate the node. I believe it was about, what, 20 channels per node in use at any-one time? Or was it 20%. Either way, the digital tier is used so little as compared to analog it's not a problem. only in systems where the good channels are still on analog like how WOW cable is. |
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RARPSL
join:1999-12-08
Suffern, NY
| reply to MacLeech
said by MacLeech :said by Joe12345678 :Things like that may end of stopping cable from having 200+ hd channels? Why? It's possible they could also just go IPTV and send just the channel requested. Without SDV or IPTV, they can't even get to 200+ HD channels because of all the other channels demanding RF spectrum. If the feed to the STB were upgraded from IPv4 to IPv6 then the SDV type channels could be sent via IPv6 Multicast which would automatically allow only one copy of the content to flow to a Node and would prevent that content from going to any Node where a STB is not tuned to the channel. |
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fiberguy
My views are my own.
Premium
join:2005-05-20
| reply to Joe12345678
That has nothing to do with it. The amount of channels will still remain proportionate to the amount of bandwidth they expect to reclaim with SDV. When you consider that they will stuff about 6 to 8 analogs into one frequency. Take a 70 channel analog basic and stuff that into digital, you'd reduce the analog burden by about 57 to 60, depending. Even if you had every typical analog in use and the 20 digital in use, you'd still only be using about 15 frequency slots in anode which is far less than before. |
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MacLeech
The one and only
Premium
join:2001-07-14
SoCal
| reply to RARPSL
said by RARPSL :If the feed to the STB were upgraded from IPv4 to IPv6 then the SDV type channels could be sent via IPv6 Multicast which would automatically allow only one copy of the content to flow to a Node and would prevent that content from going to any Node where a STB is not tuned to the channel. What's wrong with IPv4 IPTV multicast? |
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RARPSL
join:1999-12-08
Suffern, NY
| said by MacLeech :said by RARPSL :If the feed to the STB were upgraded from IPv4 to IPv6 then the SDV type channels could be sent via IPv6 Multicast which would automatically allow only one copy of the content to flow to a Node and would prevent that content from going to any Node where a STB is not tuned to the channel. What's wrong with IPv4 IPTV multicast? Simple.
With IPv4 Multicast EACH user has their own SEPARATE copy of the session between them and the Multicast Server. IOW: It is the same (ie: Equivalent to) as each user doing their own FTP Download of the stream. Thus if there are 1000 users turned to the same channel who are talking to the same Server from my Node (or Nodes that share the path to the Server that my Node is using), there are 1000 sessions and thus 1000 copies of the content flowing eating up bandwidth. Think of it like 1000 phone calls listing to the same one-way conversation.
With IPv6 Multicasting, there is one Session per Node which each user is monitoring (the User's End is a IPv6 Multicast IPN like the old IPv4 Broadcast IPN [1 bits in the Host Section of the IPN - Ex: For a /24 IPN the Bradcast address is x.x.x.255 and all nodes in the x.x.x/24 subdomain listen and hear the session]). If there are 5 nodes that are receiving the session from the Server, there are only 5 sessions with data flowing not 1000. Think of it like the old Telephone Party Line.
As an analogy, it is the difference between 1000 people driving to work and these 1000 people using buses to get to work which start at Park&Ride Parking Lots. The same 1000 people use LOTS LESS vehicles between work and the Park&Ride lots. |
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