Video streaming & net neutrality
ber.gd
ber.gd
And that's exactly what they're afraid of.
The author says that it shouldn't be treated like VOD because it is delivered over an IP network rather than old-school cable and Comcast has no right to prioritize video packets for its own IP video service over those for other IP video services (e.g., Netflix).
Which is more "neutral" is an interesting question: neutrality over the mechanism by which Comcast delivers its VOD service to cable subscribers, or neutrality between IP-based video streaming services?
To be clear, VOD streams to your STB are delivered over IP, just not through your cable modem, router and home network. You're right, of course, that Comcast claims these streams are no different than that VOD service.
The point where I think Comcast's argument falls apart is that streams to their Xbox app are delivered through the exact same network elements both inside and outside your home, as e.g., Netflix streams.
This is one of those things that seems OK from the point of view from the users short term, so there is really not too much backlash against Comcast. However, long term (as more and more people "cut the cable"), this is will bad as Comcast is setting the stage to be able to give themselves an unfair advantage in the streaming video market.
DSCP values also are completely separate from DOCSIS priority on the cable network. With DOCSIS the provider can create service flows with different priorities and bandwidth restrictions. Most providers only use two service flows (one upstream and one downstream) but if Comcast wanted to give some subset of traffic priority on the DOCSIS network (where they are most likely to see congestion) they would put that traffic into a separate service flow with a higher priority. That is how they do their "congestion management" to top users, top users in saturated nodes get their service flow priority temporary and dynamically reduced (via PCMM) so other users traffic gets first shot at open time slots.
In addition, with DOCSIS 3 it is very possible for the MSO to add a dedicated set of RF channels that only select traffic would use, which in this case it would be the Xfinity video streams. I have no idea if that is how Comcast has implemented this but if so how is that any different to Video-On-Demand on a standard STB? With standard VOD on a STB there is a set of RF frequencies set aside for VOD use. If they put Xfinity XBOX IP traffic on a separate RF channel it would be no different than adding an additional RF channel for VOD and would have zero impact on total available internet bandwidth to the cable node.
I think that "exhaustively researched" counts as gratuitous editorial spin.
The vase majority of press I read about net neutrality is done from a theoretical or policy perspective, and tends to rely on research done by 3rd parties. My aim was to distinguish that this particular post as not being yet another post of that variety.
That being said, I am fine with the editors decision to change the title of my submission.
2. It is likely these DSCP values are not used for prioritization over other services.
The most likely scenario in my mind: Comcast's trust boundaries could encompass a large enough portion of their CDN to simply not re-write of the DSCP values. Meaning this DSCP value may represent an internal network prioritization, but not impact the traffic delivery outside of their data centers. The traffic, because it originates within the trust boundary, retains its previously assigned DSCP value, but it does not indicate what policies are implemented in the actual delivery of the packet.
This post, while very interesting, simply cannot know with certainty that comcast is prioritizing traffic without conducting an extensive test. We're talking many gigabytes of traffic and many locations. However, this does warrant testing as the DSCP values could easily be used to implement prioritization.
There are quite a few ways in which traffic between different AWS components is discounted[1], or "favored" over other traffic, and this doesn't bother me a bit - it seems quite reasonable.
I lean (slightly) to the net neutrality argument, but I have a hard time seeing how the billing practices of AWS are neutral within that framework.
How does the OP feel ?
[1] For instance, bandwidth between EC2 and S3 is free.
A few points that are horribly wrong FTA (reasoning explained below):
"In order to use as few network resources as possible—both to keep costs low and quality high—these providers typically attempt to get as “close” as possible to end users, often forging agreements in which they directly connect to provider networks."
The "close"-ness that they are talking about here is not geographic closeness but network closeness. And this isn't just in terms of the distance traveled geographically, but the cost to send that traffic across some other network. That is, it is more expensive for Netflix to send traffic from their provider to (for example) AT&T to Sprint to Comcast to you, than it is to have Level3 send traffic from Level3 to Comcast to you. In fact, because of the peering agreement between Level3 and Comcast, Comcast has to pay Level3 to send them traffic (or so I believe).
The cost is not how many links it has to traverse, but the cost of the peering agreement that that network has with where it is sending the traffic.
"The only appreciable differences between the Xfinity streaming service for Xbox and e.g., Netflix, are that the source of content is within the Comcast’s “internal” CDN instead of on a third-party CDN, and that Comcast requires you to be using their own Internet service. (This is much more likely related to their agreements with content owners rather than any technical reason.) "
This is wrong. The reason is entirely financial. It is cheaper for Comcast to send traffic only within their network. If I traveled to China, it would cost Comcast much more to send the traffic to China and almost nothing to send the traffic to my computer which is Comcast's network.
"As you’ll see, the cap-exempt content is likely even more expensive for Comcast to deliver than the third party content!"
"All of these third-party streams almost certainly originate from third party providers in the Bay Area, all via direct connections to Comcast. Even though they count against my bandwidth cap, they almost certainly traverse fewer fiber route-miles and physical router ports (Comcast’s two primary costs of delivery) than the stream which originated in Seattle(!) and does not count against my cap."
Completely wrong.. Even though it is a further distance away, sending traffic from Seattle to somewhere in California is almost no cost to Comcast, so long as it stays within their network. With retrieving content from Level3 (such as Netflix movies), it has to _pay_ Level3 to send them traffic that its users want.
Again, sorry to bash on the author so much, but the author was misinformed concerning cost. Also, DSCP is kind of meaningless when traveling between networks (any network router can overwrite them and change their priority).
http://arstechnica.com/tech-policy/news/2011/02/peers-or-not...
"...they almost certainly traverse fewer fiber route-miles and physical router ports (Comcast’s two primary costs of delivery)."
That is, unless the author meant Comcast's primary costs within their network, which is not what I read it as. Without providing reference to the cost of the peering, the comparing the _geographic_ distance of traffic seemed irrelevant. Even in this case, the reason that it is more expensive for Comcast to send traffic is not that is coming from Seattle, but because they are losing money on having Level3 pay them.
Edit: I also need to read more on this as I'm curious why Level3 is paying Comcast since Comcast is (as far as I know) not acting as a transit network. But I suppose this is what happens when you violate valley-free routing.
Edit2: Also, just wanted to add, the fact that Comcast controls the peering links is why this is so sketchy. By raising the costs of peering links, they could make it way more expensive for the competitors to send their users traffic, forcing the competitors to raise their prices, allowing Comcast to be the only content provider to have reasonable prices. While the part about the bandwidth to them not counting towards your cap is sketchy, the practice of charging you less, a lower flat rate, or not at all for traffic that stays within the network is reasonable. Where it is sketchy is when that difference is leveraged to make the service cheaper. If the service is more expensive, it's the fact they are charging competitors more that is sketchy. So... in general, providing content and the network is all around sketchy.
[1] http://www.merit.edu/mail.archives/nanog/msg15911.html
Edit: Although it is not my exact area of research, a colleague of mine has done some interesting work that discusses the costs of P2P traffic for some of these ISPs that is somewhat related: http://torrentfreak.com/large-isps-profit-fom-bittorrent-tra...
The real cost in a DOCSIS network like Comcast's is actually in the last mile. DOCSIS is sort of like a mobile network in a pipe. The base station in this case is called a Cable Modem Termination System (CMTS) and data is transmitted from there over RF with QAM modulation to all the cable modems on the same coaxial segment. This can be hundreds or even thousands of cable modems. For unicast IP the packet is only received by one of them but they all have to listen.
When the radio spectrum inside the coaxial cable becomes congested the segment has to be split in two parts and a new CMTS installed, very similar to how you split a mobile network cell into sectors to improve capacity. Like with a mobile network this is capital intensive.
Not saying this makes Comcast right. But important to understand where they're coming from.
Yes, there is a cost (in terms of performance and congestion) over these links, but this not really relevant in the discussion when talking about the cost of where the traffic is originating. Whether the traffic originates in Comcast's data center in Seattle, from a CDN in Level3's network, or over their peering links with Tata, the cost of it traversing the last-mile is irrelevant. In any of these cases, traffic will still be crossing this link. And yes, this is a significant cost in terms of deploying the last-mile network, but as I said, it has nothing to do with the cost of getting of getting the packets to the DOCSIS network.
What we're saying is that if Comcast is carrying traffic from Seattle to a user in their network, they do not have to pay a transit provider to carry this traffic. If it is from Level 3, Level 3 would actually be paying them to carry that traffic to Comcast subscriber. If the traffic were coming from Comcast's peering link with Tata, Comcast would have to pay Tata (their transit provider) for the traffic.
Yes, the cost of the last-mile network is real and important, however, in this discussion it doesn't really relate, since you would be traversing the DOCSIS network in all cases.
Well, that assumption is wrong for mobile, and to some extent for DOCSIS. Last-mile cost scales with traffic volume (and completely overshadows the cost of IP transit). That's why I think you'll see MNOs and MSOs fighting the hardest against network neutrality.
The Comcast XBox VOD is only available if you're already a paying customer for Comcast Cable TV.
i.e You cannot just be a Comcast Internet subscriber without TV access and get access to the VOD streams for $x/month which are cap exempt. If this was the case, then it won't be net neutral. Thus Netflix can still compete on it's price versus Comcast TV's price. This new service is just an added delivery feature of Comcast TV.
If you are a Comcast customer, try to replicate the experiment yourself. See if you get the same results.
"Set Top Box" == Black Box.
No doubt we'll soon see one for live video (Skype).