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Why Shaping Traffic Isn't Just a Comcast Issue

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[qi:051] Recently, a brouhaha has broken out over Comcast (CMCSA), the second-largest U.S. broadband provider, and its policies regarding the management of peer-to-peer traffic. The company contests that it doesn’t block traffic to P2P services, web sites and other applications, but rather that it tries to “manage” traffic in times of congestion on various parts of its network where clogging is most acute. Semantics?

From what I understand, the company delays the P2P packets in order to decongest the network, but P2P applications by nature are set to autodial and try again. Is this an infinite delay or just a temporary management issue? Regardless of what you might think about Comcast and its policies, the issue is not limited to the Philadelphia-based broadband and TV services company. [digg=]

Comcast, according to published reports, has been using network management tools from a Canadian company called Sandvine, which is publicly traded on both the London Stock Exchange and the Toronto Stock Exchange. And if you dig through the documentation on Sandvine’s web site, it becomes pretty clear that there are other carriers out there indulging in traffic shaping and management.

Carphone Warehouse, a UK-based service provider well-known for its broken promises over free broadband, is listed as a customer of Sandvine. In a recent investor presentation, Sandvine said it had 51 cable and 38 DSL providers as customers as of the end of the third quarter, including, it bragged, 13 of the Top 100 service providers. Nearly 89 percent of its revenue came from North America.

If you correlate these facts, you know there are other big North American companies using their gear as well. In another publicly available document, Sandvine claims that “eight of the Top 20 broadband service providers in the U.S. are Sandvine customers.” Now while Sandvine has a whole slew of products, the company’s real value proposition is helping carriers make money and better manage their networks.

Growth in network traffic continues to stress network capacity due largely to the mass market popularity of bandwidth-hungry applications, such as file-sharing and streaming video from
popular sites like YouTube…By accurately identifying various “conditions” that are occurring on its network, a broadband service provider can then apply “actions” (i.e. policies) based on those conditions to pursue the broadband management objectives sought by that service provider.

Sandvine doesn’t identify its customers; it refers to them as Company A, B, C or whatever, but never by name. I guess that’s because this is potentially sensitive information and a potential PR disaster. I have left a message for their PR spokesperson, but so far no response. I am also checking with some of the major broadband providers. An AT&T (T) spokesperson emailed with this:

AT&T does not treat P2P traffic any differently than other Internet traffic. And, we are not a customer of Sandvine. Beyond that, we do not comment on vendor relationships outside of product announcements.

We will update the story as we hear from others, but one thing is becoming quite clear — this won’t be the last time you’ll hear the phrase “traffic shaping.”

Update: A spokesperson for Cox Communications’ high-speed Internet division said, via email:

As with any ISP, Cox uses a variety of tools to make sure all our customers have the best possible customer experience with our high-speed Internet service. However, to protect the integrity and security of our network, we don’t disclose specific methods or vendors used.

33 Responses to “Why Shaping Traffic Isn't Just a Comcast Issue”

  1. AnomynousPierson

    I’m sick of hearing about how traffic shaping is a good thing(in this context) and that people shouldn’t have to suffer for other people downloading. If you are suffering because other people actually use the bandwidth that they pay for then your ISP is to blame. I have a connection with 15mb down and 2mb up unlimited for a monthly fee. If I want to max that connection 24/7 you bet your ass I will. I paid for it and it’s mine. It’s my ISPs responsibility to ensure it has the bandwidth to cover me and everyone else on their network. If there are latency issues it’s because of poor planning on the part of your ISP. Stealing the bandwidth back from the users that pay for it is just wrong no matter how you slice it.

  2. To add to that if Comcast is forced to use traffic shaping to continue giving all users quick speeds then they obviously do not have sufficient systems to keep up with what they offer.

  3. Kumar I have to say your belief is amazing. If I am paying for 6Mbps DL I expect it. I also expect the UL speeds I pay for, how I choose to use the internet is my choice so long as I am not participating in illgal activities I find it unfair for Comcast to limit bandwidth as soon as people start using what they pay for.

    Comcast has recently seemed to have made their traffic shaping worse by the way as they now reduce my internet to approx 1kbps DL speeds and 4-5 up. The only way I can fix this after running torrents is to go reset my modem which is a bit ridiculous. After calling Comcast they informed me that there is NO guaranteed minimum speed only a maximum so according to my contract I could get as little as 1bps up and won.

  4. TechWannabe

    There is a great article in PC Magazine about ISP’s and the “lies” they like to tell about internet speeds and traffic shaping. Check it out…it’s definitely entertaining!,2704,2155140,00.asp

    By the way, the NetEqualizer is a product that really does traffic shaping and bandwidth management without blocking P2P services, web sites or other applications that use a lot of bandwidth. It really does just “manage” the traffic by internally slowing down traffic that is eating up all the bandwidth and letting other traffic through quickly. It’s pretty amazing. You can actually try it out at

  5. To the people who say its acceptable to slow down other people so they get the speed they “should” get. If people are paying for a set upload and download rate, then its the fault of the provider if they oversell and can’t provide the bandwidth to the customer.

    Take the analogy of the roadway. If a road is overcongested, we can’t blame other drivers and say that they have no right to be driving all the time. Traffic shouldn’t be bumped or “policed” of those roads unless the roadway is marked as no trucks or a HOV lane or some such. In this case, comcast was selling their “roadway” as it were, as clear for all traffic but selectively policing and saying, no trucks, no large vehicles, no recreational drivers etc.

  6. Re: Verizon’s FIOS

    They too packet-shape. Not sure if they use Sandvine, but it is very evident that they are using some sort of algorithm for throttling p2p traffic.

  7. Nonymous

    we aint seen nothing yet… Boxes like Zeugma’s can do a lot more on a per-session OR per-App-flow basis so while a Comcast may choose to throttle p2p app traffic, they will let an upload to Shutterfly go through just fine….

    And then there is NebuAd — to serve up ads BASED on the sessions/apps/policies ISPs want to data-mine.

  8. I don’t have any BitTorrent traffic, but it ISPs are traffic shaping, why stop there? If I’m using a VOIP provider over my Comcast line, why would they not deteriorate that to push me towards their proprietary option (Assuming the Telcos don’t litigate the independent VOIP providers out of existence first).

  9. I found the comment by the AT&T spokesperson particularly delicious.

    “AT&T does not treat P2P traffic any differently than other Internet traffic.”

    Meaning: we shape ALL our traffic.

  10. Anonymous

    Many appear to be using morality to justify Comcast’s actions – “Most of Bittorrent carries pirated traffic, so it’s okay for Comcast to slow them down”.

    This an illogical argument. It not acceptable for Comcast to be slowing down ANY content. The nature of the content should not even be a factor.

    Can you imagine if they slowed down gamers? There’d be such a ruckus – gamers want to be as close to 0 ping as possible. Gamers will simply pack up and switch ISPs.

    Now, looking at this mess, doesn’t this provide Comcast with an opportunity to upsell to people who want more? Look at Verizon with 20 MB up/down FIOS.

    It’s too bad that we can’t make such a fuss about Rogers in Canada.

    Furthermore, I’m ashamed that Sandvine is a Canadian company.

  11. cat mouse cat mouse … the Sandvine system can be defeated with the click of your mouse in MS Windows and your favorite peer to peer algorithm. Likewise most of the p2p systems can be defeated using surprisingly simple things like Windows Firewall… etc… cat mouse cat mouse …

  12. Om,
    I agree with K Kumar that a little “traffic shaping” can be a good thing, to make sure the many don’t suffer to much at the hands of the few. Of course, this is a slippery slope, and a little traffic shaping can lead to mass paranoia about Comcast (or other service providers) crippling competing VoIP services, or committing other breaches of the unwritten rules of Net Neutrality. For now, I’m not convinced that Comcast is taking it too far. And, as a Comcast subscriber, I appreciate that they take action when my neighbors start hogging all the bandwidth with their P2P apps.

  13. Om,

    I’m a Networking Entrepreneur and an avid user of the Internet (including videos, P2P, podcasts, etc.).

    First, Comcast is not alone in using Traffic Management gear – virtually every provider I’ve talked to, does traffic management. I am sure AT&T uses a competitor to Sandvine, maybe not exactly the way Comcast does.

    Second, Comcast allows me to get higher bandwidth by the PowerBoost option (for relatively smaller files) than my configured bandwidth – that’s Traffic Management too, and hey, it’s good for customers!

    Third, as a customer of Comcast, I’d much rather prefer they slow down the heavy P2P users who are contributing to my getting less bandwidth than I should. I am on the same, shared network (upstream AND down) and my Skype/VoIP sessions and Youtube video shouldn’t get interrupted because someone is downloading videos via P2P (and even today, most are pirated).

    Last, but not the least, P2P is built to adapt around slow links. It’s a fundamental flaw in P2P – as long as that exists, operators will use it to slow them down.

    That’s why we did things differently with the TellyTopia algorithm, rather than using P2P, and you’re going to see it more and more.

  14. Om,

    For what it’s worth, I spent a good deal of time yesterday talking with all the right people at Comcast. They were surprisingly very forthcoming, in contrast to their initial uptight reactions, and they offered a lot more insight into the issue.


    According to one executive, Comcast’s configuration is set so that the P2P upload will keep trying until it goes through. I agree on the semantics points, however.

    Still, there are a lot of unanswered questions about how all this P2P traffic is being managed.

    Cynthia B.