He said, she said: Is Comcast prioritizing traffic or not?

comcast van

Comcast, once again, has some explaining to do. An engineer has conducted experiments that he says show the nation’s largest broadband provider is prioritizing traffic– something it’s not supposed to do under the conditions the government imposed when the cable company bought NBC-Universal. At issue are the methods and arguments Comcast uses to exempt some of its Xfinity on-demand traffic from its broadband cap.

Comcast categorically denies it’s prioritizing traffic, but the issue is sure to dog the cable provider in the near term, much like the back and forth that ensued back in 2007 when it was caught blocking P2P traffic. Comcast sent me the following statement:

“It’s really important that we make crystal clear that we are not prioritizing our transmission of Xfinity TV content to the Xbox (as some have speculated). While DSCP markings can be used to assign traffic different priority levels, that is not their only application – and that is not what they are being used for here. It’s also important to point out that our Xfinity TV content being delivered to the Xbox is the same video subscription that customers already paid for and is delivered to their home over our traditional cable network – the difference is that we are now delivering it using IP technology to the Xbox 360, in a similar manner as other IP-based cable service providers. But this is still our traditional cable television service, which is governed by something known as Title VI of the Communications Act, and we provide the service in compliance with applicable FCC rules.

After two separate blog posts appeared last week showing that Comcast was labeling packets on its network with different quality of service marks, many folks in the industry raised their eyebrows and a few started feeling around for people to conduct reliable tests. I spoke to people in ISPs, Washington circles, and at web companies about Comcast’s actions. They noted that it did look like Comcast was marking packets, but proving that it was prioritizing them in defiance of the FCC and DoJ merger conditions wasn’t obvious.

Proving prioritization is no easy task.

Meanwhile Bryan Berg, the Founder and CTO at MixMedia was making a mess in his living room trying to prove that Comcast wasn’t just trying to mark its traffic for counting elements of it against a cap, but was indeed giving its Xfinity service delivered via the Xbox precedence over normal traffic. From the blog:

What I’ve concluded is that Comcast is using separate DOCSIS service flows to prioritize the traffic to the Xfinity Xbox app (so that I’m using consistent terminology, I’m going to call this traffic “Xfinity traffic” in the rest of the post). This separation allows them to exempt that traffic from both bandwidth cap accounting and download speed limits. It’s still plain-old HTTP delivering MP4-encoded video files, just like the other streaming services use, but additional priority is granted to the Xfinity traffic at the DOCSIS level. … In addition, contrary to what has been widely speculated, the Xfinity traffic is not delivered via separate, dedicated downstream channel(s)—it uses the same downstream channels as regular Internet traffic.

He then offers some speculation that Comcast is actually paying more per bit to send its Xfinity traffic via the Xbox and back around to the end consumer, which means that this prioritization isn’t done to save Comcast money. The obvious reason he implies, is because Comcast wants to create an unfair advantage over other video-streaming apps that will fall under the cap. An argument that I and several other people have made.

Berg’s chart showing Xfinity over Xbox traffic getting prioritized despite Berg flooding the connection.

Berg’s post is detailed (it has pretty charts!) and Berg lays out his methodology and offers the code he used, so others can replicate his experiments. I’d be curious to hear if others have tried to prove that Comcast is prioritizing traffic, and what they are discovering. Comcast clearly says it is not, but it also vehemently denied that it was blocking P2P packets back in 2007 and 2008 even though the results of it’s actions ended up in P2P downloads getting blocked.

Comcast’s actions violate two principles.

So, if Comcast is prioritizing its Xfinity traffic going over the Xbox, there are two problems that will have to be addressed: one related to Comcast and the other related to the FCC’s regulations covering network neutrality.

For Comcast specifically, when it received approval to purchase NBC-U, the DoJ and FCC said it would have to follow certain merger conditions. Those conditions explicitly state it can’t treat its own traffic differently under its cap, and many people believe that its decision to exempt Xfinity traffic streamed via the Xbox was alone a violation of the agreement.

Now, however, if the FCC can prove that Comcast is prioritizing certain elements of its own traffic, then it is clearly violating those conditions. Of course, then the FCC or the DoJ, would have to take some kind of action against Comcast, and so far both agencies have proven slow to react to other allegations that Comcast was violating its merger conditions. From the conditions:

If Comcast offers consumers Internet Access Service under a package that includes caps, tiers, metering, or other usage-based pricing, it shall not measure, count, or otherwise treat Defendants’ affiliated network traffic differently from unaffiliated network traffic. Comcast shall not prioritize Defendants’ Video Programming or other content over other Persons’ Video Programming or other content.

The second issue is a larger problem for the overall industry, and deals with a loophole in the FCC’s network neutrality regulations that were proposed in 2010 and are currently the subject of a lawsuit filed by Verizon. The regulations don’t forbid what Comcast is doing specifically, but exempting Comcast’s own Xfinity service delivered via the Xbox (and TiVo) from its data cap is a roundabout way to discriminate against other traffic that isn’t exempt. In that sense it violates the spirit of the regulations. Which means that the merger conditions are largest stick that opponents can wield against Comcast’s actions.

So what’s next on the regulatory front?

Most of the people I spoke with who have experience in politics expect that if Comcast is challenged it will be on the economic advantage is has created for itself because it owns both the last-mile access, a cable business and a content company. Unfortunately such a challenge ignores the fundamental problem with U.S. broadband: it’s not very competitive and the agency charged with regulating it has classified cable Internet as something that lays outside of its authority (for the details on this fight see this GigaOM Pro report (sub req’d).

Ironically the fight that stripped the FCC of much of its authority to regulate cable services, and still to this day puts its network neutrality rules on somewhat shaky legal ground was Comcast’s lawsuit against the agency, after the FCC had censured the cable company for blocking P2P traffic. Comcast is playing a long game here, and it’s unclear how far the FCC can push to protect consumers against its behavior even if it wanted to close that loophole in its network neutrality rules. For now the best bet for enforcement is the NBC-U conditions. Too bad they expire in January 2018.

Comcast van image courtesy of Flickr user Titanas.


Comments have been disabled for this post