Video streaming & net neutrality

http://ber.gd/post/22374588073/video-streaming-net-neutrality

by dalton • 14 years ago

111 25 14 years ago

slapshot• 14 years ago

To be clear, this is a discussion of "net neutrality" in that the author alleges that Comcast is prioritizing (and not charging for) traffic for its Xbox streaming media application, which works like a Video-on-Demand service. Comcast claims that this is similar to a standard Video-on-Demand service based in a cable box and can legally be prioritized because it is the functional equivalent of traditional VOD. Comcast doesn't see anything wrong with not charging for bandwidth used for set-top-box VOD, and analogizes that to Xbox VOD, even though the two may use different underlying technologies.

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?

bdb• 14 years ago

Hi. I'm the author of the original post; thanks for your comment.

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.

ismarc• 14 years ago

This is a point that is frequently missed and ends up muddying the actual net neutrality discussion. For cable providers, Internet (big I internet, not just a network that uses the same protocols) is carried on certain channels with vod and normal cable channels carried on other channels. For providers like Uverse, it's not separate frequency channels, but separate vlans with dedicated bandwidth on each (very similar model, though, big I internet traffic is separate from other services). Where the neutrality line is crossed is when all traffic on the big I Internet segment isn't treated equally. In this case, the separation of billing is giving that traffic preferential treatment over other big I Internet video streaming.

dfxm12• 14 years ago

Comcast must envision a future where their set top boxes will be replaced with other appliances that can run the Comcast VOD "app" currently available for XBox. They're trying to set a precedent now, so that when there is no non-video streaming "analogy" or "equivalent" to this service they can claim that it is OK to not cap their own service since they've always done it that way.

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.

modeless2• 14 years ago

This better get investigated at least as thoroughly as the Street View WiFi thing. Unlike that situation, this is actually causing quantifiable harm to consumers right now (as Comcast would otherwise actually be forced to raise their data caps to provide this service, improving consumer choice by making alternatives more viable).

seanp2k2• 14 years ago

>"improving consumer choice by making alternatives more viable"

And that's exactly what they're afraid of.

nightpool• 14 years ago

Can you change the title to match the actual article? I belive that the Hacker News guidelines suggest to keep the submission title as close as possible to the new one. (esp. in cases like "exhaustively researched")

Locke1689• 14 years ago

Check it again; you're wrong.

scott_s• 14 years ago

From the guidelines: You can make up a new title if you want, but if you put gratuitous editorial spin on it, the editors may rewrite it.

I think that "exhaustively researched" counts as gratuitous editorial spin.

pdubs• 14 years ago

Not to mention that, though it's a nice simple technical evaluation based on packet header inspection, it's far from "exhaustive".

tonyb• 14 years ago

The DSCP values have nothing to do with the bandwidth cap. DSCP is just a "flag" on the packet and most internet routers don't look at that at all. I would also be very shocked if DSCP has anything at all to do with the way Comcast is calculating your bandwidth cap. They are most likely using something like IPDR or subscriber-aware DPI.

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.

modeless2• 14 years ago

The real problem here is that "net neutrality" is a farce as long as providers are allowed to send their most lucrative services over non-neutral channels.

thespin• 14 years ago

If others can replicate what the author did, then it might rise to the level of "exhaustively researched".

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).

kozubik• 14 years ago

How do the traffic exemptions in AWS fit into this net neutrality debate ?

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.

noobface• 14 years ago

1. It's possible to rewrite DSCP values at each hop.

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.

zbisch4• 14 years ago

I'm sorry to sound very negative on the author, but I don't know how you could have the knowledge to write this article, but not have the knowledge to understand the basics of costs on the Internet.

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).

wmf2• 14 years ago

It has been reported that Level 3, Akamai, and Limelight are paying Comcast and delivering content as close to the user as possible, so I agree with the original author that external content would seem to be cheaper than Comcast's internal CDN (maybe even a profit center).

http://arstechnica.com/tech-policy/news/2011/02/peers-or-not...

http://apps.fcc.gov/ecfs/document/view?id=7021030795

zbisch4• 14 years ago

Ah, very good point. The last thing I read on the Level3/Comcast spat story lead me to believe Comcast was paying Level3 for the peering. I apologize. However, this line lead me to believe the author had a misunderstanding of the costs of traffic:

"...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.

recoiledsnake• 14 years ago

I am shocked that everyone here seem to be ignorant of this very important fact:

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.

Video streaming & net neutrality

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