Why can I watch cable TV 24/7 but streaming video has a cap?
January 10, 2019 2:37 PM Subscribe
I get TV from the cable company, and I get internet from the same cable company. It's all bits of electronic data that come through a coax cable into a box in my house, then into my screen devices. I can leave the TV on TBS and watch Friends 24/7 for the whole week and nobody cares ... but I can only use X-hundred GB of data before the cable company will cap me for the month, so I can't stream Friends on Netflix 24/7 in the same unrestricted way.
Why? Isn't it all the same electronic stuff coming through the same entry point? Is this just an artificial business constraint that the cable people have put in place to make more money? Or is there something technical that I don't understand that makes the two things not apples-to-apples?
Why? Isn't it all the same electronic stuff coming through the same entry point? Is this just an artificial business constraint that the cable people have put in place to make more money? Or is there something technical that I don't understand that makes the two things not apples-to-apples?
Briefly, your cable company is sending that same TBS signal all over their network
Not these days, not if it's an IP based set-top box. It really is all IP packets. They're only sending you the channel you're watching, not every channel you get. There isn't enough bandwidth for that in the world of getting 500 channels.
The only difference is interchange. When you watch Friends all the data is within the cable co's network - it goes from their servers to your STB. When you stream from Netflix it has to go over the public internet and through exchange points to get to you.
At least that's the simplified model - in practice really big streamers like Netflix and YouTube have private exchanges with major ISPs so the traffic doesn't have to go all over the place to get to you.
Is this just an artificial business constraint that the cable people have put in place to make more money?
Basically, yes. You're being sold a consumer-grade service whose price is based on usage assumptions. So they put those usage assumptions into your service agreement. It gives them a contractual justification to kick you off if they want.
Or is there something technical that I don't understand that makes the two things not apples-to-apples?
Internet exchange or peering. But these days, no, not really. Peering isn't the big deal it once was and edge caching further reduces true Internet traffic. It's just a made-up limit.
posted by GuyZero at 2:59 PM on January 10, 2019 [8 favorites]
Not these days, not if it's an IP based set-top box. It really is all IP packets. They're only sending you the channel you're watching, not every channel you get. There isn't enough bandwidth for that in the world of getting 500 channels.
The only difference is interchange. When you watch Friends all the data is within the cable co's network - it goes from their servers to your STB. When you stream from Netflix it has to go over the public internet and through exchange points to get to you.
At least that's the simplified model - in practice really big streamers like Netflix and YouTube have private exchanges with major ISPs so the traffic doesn't have to go all over the place to get to you.
Is this just an artificial business constraint that the cable people have put in place to make more money?
Basically, yes. You're being sold a consumer-grade service whose price is based on usage assumptions. So they put those usage assumptions into your service agreement. It gives them a contractual justification to kick you off if they want.
Or is there something technical that I don't understand that makes the two things not apples-to-apples?
Internet exchange or peering. But these days, no, not really. Peering isn't the big deal it once was and edge caching further reduces true Internet traffic. It's just a made-up limit.
posted by GuyZero at 2:59 PM on January 10, 2019 [8 favorites]
GuyZero wrote: Not these days, not if it's an IP based set-top box. It really is all IP packets. They're only sending you the channel you're watching, not every channel you get. There isn't enough bandwidth for that in the world of getting 500 channels.
IP Set-top boxes are a relatively small percentage of the market, especially in the US. Over time, yes, video will be delivered over IP, but today, most video is delivered over HFC using QAM. This link seems like a decent explanation of the difference -- scroll down to Television Networks In Detail.
There is something called Switched Digital Video that does only deliver the channels currently being tuned to by the service group which only sends channels currently in use, but it requires more capable STBs (to communicate back to the cable head end) and not all cable providers use it.
posted by elmay at 3:07 PM on January 10, 2019 [6 favorites]
IP Set-top boxes are a relatively small percentage of the market, especially in the US. Over time, yes, video will be delivered over IP, but today, most video is delivered over HFC using QAM. This link seems like a decent explanation of the difference -- scroll down to Television Networks In Detail.
There is something called Switched Digital Video that does only deliver the channels currently being tuned to by the service group which only sends channels currently in use, but it requires more capable STBs (to communicate back to the cable head end) and not all cable providers use it.
posted by elmay at 3:07 PM on January 10, 2019 [6 favorites]
There is essentially no actual reason to limit data usage. Bandwidth yes, data usage, no. It’s just a money grab because they can.
posted by Automocar at 4:02 PM on January 10, 2019 [1 favorite]
posted by Automocar at 4:02 PM on January 10, 2019 [1 favorite]
When you stream from Netflix it has to go over the public internet and through exchange points to get to you.
Not as much, anymore.
Larger content providers like Apple and Netflix have content caches inside the cable company's facilities to minimize the actual traffic that's going out over the public internet.
A friend of mine runs IT for a large college campus and confirms they have Apple and Netflix CDNs installed there as well.
posted by JoeZydeco at 4:14 PM on January 10, 2019
Not as much, anymore.
Larger content providers like Apple and Netflix have content caches inside the cable company's facilities to minimize the actual traffic that's going out over the public internet.
A friend of mine runs IT for a large college campus and confirms they have Apple and Netflix CDNs installed there as well.
posted by JoeZydeco at 4:14 PM on January 10, 2019
There is essentially no actual reason to limit data usage. Bandwidth yes, data usage, no. It’s just a money grab because they can.
This is only sort of true. Data caps allow the ISP to make more efficient use of the available bandwidth.
Say a neighborhood has a 10Gbps fiber optic trunk cable serving 1,000 homes. One option would be for the ISP to just sell everybody a 10Mbps connection and be done with it. Since most people's internet access patterns are very irregular, a huge fraction of that bandwidth would be idle at any given moment.
Instead, they sell you an "up to" 100Mbps connection, but limit your total data usage to 1TB per month. For an average user, this is a better deal, because pages and downloads normally finish 10 times faster. The data cap prevents everyone from trying to use 100Mbps all the time, which would be too much for the trunk to handle. (Of course the downside is that you can still get congestion if more than 10% of the users are trying to use their full allocation simultaneously. But that would take a lot more than just, say, everyone deciding to watch Netflix at once.)
You can look at this as just "cutting costs" to be stingy, or you can look at it as offering a mostly-better service using the same amount of infrastructure; it's a matter of perspectuve.
posted by teraflop at 4:31 PM on January 10, 2019 [1 favorite]
This is only sort of true. Data caps allow the ISP to make more efficient use of the available bandwidth.
Say a neighborhood has a 10Gbps fiber optic trunk cable serving 1,000 homes. One option would be for the ISP to just sell everybody a 10Mbps connection and be done with it. Since most people's internet access patterns are very irregular, a huge fraction of that bandwidth would be idle at any given moment.
Instead, they sell you an "up to" 100Mbps connection, but limit your total data usage to 1TB per month. For an average user, this is a better deal, because pages and downloads normally finish 10 times faster. The data cap prevents everyone from trying to use 100Mbps all the time, which would be too much for the trunk to handle. (Of course the downside is that you can still get congestion if more than 10% of the users are trying to use their full allocation simultaneously. But that would take a lot more than just, say, everyone deciding to watch Netflix at once.)
You can look at this as just "cutting costs" to be stingy, or you can look at it as offering a mostly-better service using the same amount of infrastructure; it's a matter of perspectuve.
posted by teraflop at 4:31 PM on January 10, 2019 [1 favorite]
The efficient use of bandwidth is a major factor, described very well by teraflop, above. The connection cable internet offers is shared with the local network, and it is well below the capacity required if everyone used it to the fullest at the same time, but that's a thing that is not likely to happen if they hedge their promises about full bandwidth, and also cap your data to discourage your 24/7/max bw usage.
Additionally, you pay for home internet; they also sell business internet, and they do not want to enable you to run an internet-based business through the cheaper home internet option, where in this case running a business means having servers in your house which are uploading/downloading all the time to serve your customers. Here, business generally means a filesharing site or porn site; they're not worried about you hosting your lawnmowing service website that's seen by a hundred people a month.
And finally, there's the market-- they don't have to offer you good service for good value-- they do it because their competitors, insofar that they have any, force their hand, and so far as their TV customers force their hand. They want you to be paying them hundreds a month for all of your telecom services bundled together. So they have come up with whatever will sell to the most customers paying the most money without leaving for satellite TV, major cellphone carriers, baby-bell DSL, cable internet competitor (again, where applicable), or just putting up a dang antenna on their roof.
posted by Sunburnt at 5:20 PM on January 10, 2019 [1 favorite]
Additionally, you pay for home internet; they also sell business internet, and they do not want to enable you to run an internet-based business through the cheaper home internet option, where in this case running a business means having servers in your house which are uploading/downloading all the time to serve your customers. Here, business generally means a filesharing site or porn site; they're not worried about you hosting your lawnmowing service website that's seen by a hundred people a month.
And finally, there's the market-- they don't have to offer you good service for good value-- they do it because their competitors, insofar that they have any, force their hand, and so far as their TV customers force their hand. They want you to be paying them hundreds a month for all of your telecom services bundled together. So they have come up with whatever will sell to the most customers paying the most money without leaving for satellite TV, major cellphone carriers, baby-bell DSL, cable internet competitor (again, where applicable), or just putting up a dang antenna on their roof.
posted by Sunburnt at 5:20 PM on January 10, 2019 [1 favorite]
Some pondering.
Not all Cable companies do broadcasts over IP. Plenty are still just channel assignments. (I asked my cable installer about this because I was expecting some sort of IP box... nope).
Even in IP land if they're smart... broadcast TV does not take a separate stream for every viewer. They probably use some sort of multicast where the box asks the switch for a stream and the already running stream gets routed to the switch. It doesn't matter how many homes are tuning into that same station at the same time, there's only one broadcast/multicast stream of that content on the trunk.
It's only the on-demand streaming sort of things that require a separate stream for each viewer.
this is mostly from big uni network experience with caches and CDNs and gigapop peering arrangements, not from commercial cable/fiber/dsl end of things.
The worst bit would be that last mile on coaxial cable where N households are sharing the same physical layer.
posted by zengargoyle at 11:46 PM on February 6, 2019
Not all Cable companies do broadcasts over IP. Plenty are still just channel assignments. (I asked my cable installer about this because I was expecting some sort of IP box... nope).
Even in IP land if they're smart... broadcast TV does not take a separate stream for every viewer. They probably use some sort of multicast where the box asks the switch for a stream and the already running stream gets routed to the switch. It doesn't matter how many homes are tuning into that same station at the same time, there's only one broadcast/multicast stream of that content on the trunk.
It's only the on-demand streaming sort of things that require a separate stream for each viewer.
this is mostly from big uni network experience with caches and CDNs and gigapop peering arrangements, not from commercial cable/fiber/dsl end of things.
The worst bit would be that last mile on coaxial cable where N households are sharing the same physical layer.
posted by zengargoyle at 11:46 PM on February 6, 2019
This thread is closed to new comments.
When you watch Friends on Netflix, your session is set up specially for you. If your neighbor is watching Friends on Netflix, they have a different session. Even if it is exactly the same episode and they start, stop, and pause at exactly the same time. So, twice as much network bandwidth is used for the two views versus if you were both tuned to TBS.
posted by elmay at 2:50 PM on January 10, 2019 [6 favorites]