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FCC Asks if Comcast Slows Rivals' VoIP Traffic

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Looks like Comcast’s (s CMCSA) new network management plan is drawing the ire of competing Voice over IP providers and the scrutiny of federal regulators. The plan, which is detailed here, basically slows bandwidth hogs broadband speeds during times of congestion at a particular node. Apparently, it also has the unfortunate side effect of lowering voice quality for VoIP services — including those offered by Comcast’s competitors. More interestingly, Comcast advertises that its own digital calling service (a variation on VoIP) is unaffected by such network slowdowns, and the FCC wants to know why.  In a letter filed on Sunday, the FCC asks Comcast:

We request that Comcast explain why it omitted from its filings with the Commission the distinct effects that Comcast’s new network management technique has on Comcast’s VoIP offering versus those of its competitors. We also ask that you provide a detailed justification for Comcast’s disparate treatment of its own VoIP service as compared to that offered by other VoIP providers on its network.  In particular please explain how Comcast Digital Voice is “facilitites based,” how Comcast Digital Voice uses Comcast broadband facilities, and, in particular, whether (and if so, how) Comcast Digital Voice affects network congestion in a different manner than other VoIP services.

Comcast has until Jan. 30 to respond to the FCC, and a spokeswoman said the cable provider was reviewing the letter. In an emailed statement she said, “We have fully complied with the FCC’s order regarding our congestion management practices.”

My guess from talking to other cable voice providers is that Comcast will make a distinction between VoIP traffic that travels across the public Internet and its own digital voice service, which Comcast tries to route across its own broadband pipes. Looks like Comcast will have to rev up its marketing machine before the new Commission to explain how this version of network management is better than its previous P2P throttling efforts. The Commission wasn’t impressed last time; will Comcast’s arguments pass muster with the incoming regulatory team?

29 Responses to “FCC Asks if Comcast Slows Rivals' VoIP Traffic”

    I HAVE A COMCAST connection.
    Speed test:

    11 mpbs D and 3 mbps U .

    IN-SPITE of this I keep getting fading and totally crappy voice from Skype – like waxing and waning effect hearing opp side. Opp side also can hear only my broken bits and pieces.

    Then I switched immediately to DSL from SBC ( neighbor’s ) :
    3 mpbs D and 0.78 mbps U .
    and I can hear skype CLEARLY.

    SO yes it is a comcast thing looks like. But I had the same provider at the place 40 miles away and never had this problem. THIS STARTED FOR ME LIKE SINCE I MOVED TO THIS NEW PLACE !!!!
    I deleted the shared.xml file everytime ( that has the methods skype uses to contact other service providers ) to see if it helped. I doubt it did .
    I dont know what’d be the problem. HOW does comast ID a Skype Packet.
    I had disconnection problems over a COMCAST connection for justvoip too but less bad as skype. Skype was the worst.

    • Patricia

      I am a comcast user, and I am complaining.

      I’ve had the same drop outs using skype.

      On 2 different types of operating systems. One Ubuntu running skype for Ubuntu, and running skype on windows 7. Both drop out on wired connection, and wireless.

      This has been an ongoing problem for over a year, and comcast refuses to address the issue or flat out denies any issues. Typical.

  2. Vonage over Comcast in Rockville Maryland is terrible. The upload speeds slow to zero so the call recipient cannot hear you but you can hear them.

    A temporary solution is to reboot the cable modem which gets a fresh connection and things are fast again for a few minutes before Comcast hammers Vonage again.

    I do not trust Comcast.

  3. bjornski

    I’ve just been slammed hard by Comcast and their “traffic management”.

    If I even load up any torrents, even with minimal settings (10 connections max, 1 file at a tme, 100k down, 10k up), if I connect to ONE peer, my web browsing speeds drop to zero (or nearly) for 15 minutes.

    That’s bad enough.

    I also have a MagicJack telephone device. I’ve now found that when I make/get calls with it, it seems to “clog” those same network management nodes, and “bam!” – Internet speeds are cut to zero for 15 minutes.


    Protocol-agnostic, my butt.

    And last night, when my speeds finally came back? I started looking for competitors in the area (Minneapolis = no competition). And know what I was running into?

    Network speeds being determined by WHAT I WAS SEARCHING FOR! I could do my daily reading, (politics comedy) just fine, but toss in “ViOP” or “torrent” into the Google search, and BAM! Slow-speeds again.

    I hate Comcast with the energy of 1000 burning suns. Our state governor should be HUNG for allowing this monopoly to stay in place.

    But he likes their donation checks (and his quest to run for President in 2012) more than he likes the citizens.

    BOYCOTT COMCAST! Get DSL and Dish network instead.

  4. I would bet everything I’ve got that Comcast is screwing with customers who choose a different VoIP service than theirs. I have been with them (not happy about it, but they bought out RoadRunner in Lake City so I had no choice in the matter) for around 4 years or so. Their speed and service is sub-par at best.

    What really clued me in is how bad my internet service declined the day I hooked up Vonage. Now almost every site I try to visit is SUPER-SLOW to connect or it times out both in IE and FF browsers. It matters not if it’s online banking or just visiting a site – it drags and drags and then gives an error page about the slow connection, etc.

    I must say that the Vonage service is amazing – I quit AT&T and the call clarity and quality is excellent, so it’s the internet connection that I’m upset about… so much so that if I cannot resolve it, I’ll have to go back to regular telephone and I don’t want to.

    I agree with several of you and I think that they are pulling some sleazy tricks and hope that the FCC gets all over them (the FTC too, for that matter – there should be freedom of choice!).

  5. I’m in Washington DC and am getting 20 Mbps down and 3 Mbps up, but 20-28% QoS using various VOIP tests. I’ve got a service call in a couple of days. I’ll post if there’s anything interesting that comes up.

  6. Techietype

    I definately think that Comcast is downgrading the QOS on third-party VoIP packets! I have their standard residential high speed internet, and my service speed is a whopping 11-11.5 Mbps down and 4.5 Mbps upstream – which is very fast compared to the cable internet benchmark. What I noticed, when conducting various VoIP-specific tests, is that even with low jitter levels and a fast up/downastream is that the QoS measurement of my VoIP packets is less than 32% on average. That’s why I have such terrible sound quality problems when I try to use a third party voip service from my home. I have CDV (Comcast Digital Voice), with two lines, and never have any issues with them. It’s all just a bit too suspicious… And I noticed that over the past 2 months or so, it seems as though the QoS on my VoIP packets has been getting progressively worse! I used to be able to use third party voip at home about 6 months ago with no problems, but lately something has been up!

  7. anil singhal

    regarding that testing link – that proves it! it’s a comcast issue. i also have DSL connected today and tested with that link against comcast. the DSL has a jitter free line and high QoS while the comcast fails one or both at least in 30% of my repeat testing.

    thanks for this great link!

  8. Kregg Kiel

    I use an Ooma and noticed a buzzing on incoming voices. It all goes to Quality of Service. I think Comcast has horrible QOS issues. I ran this test and it never comes up with good Quality of Service.

    Of course, it’s not a problem for their VOIP. One assumes they “treat” the signal in order to work with their VOIP. I hope the FCC evens the field with these idiots.

  9. anil singhal

    Since late January of 2009 my Vonage service is essentially USELESS on COMCAST. PING speeds (which should be much less than 120ms) are inconsistent. out of a run of 100 pings, about 5-10% are above 150ms, causing choppy voice quality. COMCAST has been out to my home 7 times! first saying there needs to be a filter on the line, then changing inside wiring, then changing my modem, then changing street wiring, then saying maybe there’s a hum on the line but they’re not sure. I even went from basic (about 2mb down, 1mb up) to Blast (16mb down and 2-3mb up). the speed of overall downloads is fine but the i still have poor ping speeds. This results in my uploaded voice not being heard properly on the other side, but my listening to them is perfect. FYI, Vonage tried to help several ways. finally i went to my neighbors house and tried my vonage box on his SLOWEST ATT DSL service (about 1mb down, 400kbbs up) and there was NO sound issue and the ping speeds consistently less than 50ms. I’ve done this test over 10 times. Any suggestions welcomed! (I’m actually going to install DSL and comcast)

  10. We’ve been comcast and vonage customers over 3 years in evanaston, Il area. Suddenly vonage is absolutely unusable. This happened right after Comcast’s free bandwidth upgrade for all its customers. Im quite certain they are routing voip packets seperately, would like to be proved wrong.

    I hope this inquiry gets to the bottom of it.

  11. I have been using Skype since 2004 and in the last 2 to 3 months my skype has gone slow. There is a marked 0.6 to 1.5 seconds delay while talking and sometimes it is annoys people on the other end who think that I am not replying to them quick enough.

    This is annoying me and not sure what I can do as I have no other choice for broadband where I live.


  12. Karen J.

    My husband and I have been a Vonage customer for four years and Comcast customer for five. Our experience is that within the last two months Comcast is slowing down our service and now our calls break up. Before that our Vonage service was perfect.

    Comcast is famous for lowering the quality of the service while keeping prices the same. So customers pay more for less service. I’m sad that they are obviously doing it again.

  13. We are a new user of Vonage and Comcast both. We have residential Comcast for our ISP and which started in Nov. 08 and Vonage that started a week later. As of beginning of this year we have started to have problems with our VOIP, no amount of tech support has helped reducing the gibberish others hear when they call our number.

    At this point, I have no doubt Comcast is tinkering with our service!

  14. Thomas v

    Most of US Pay a fair dollar for our “High Speed Internet Connection” and ex speck to be able to do more then just bang around on web sites and read e-mail. What is the point of paying for all this bandwidth and not being able to access it, especially with another paid service (VOIP).

    It seems clear they want to sell us a service but limit our access to it. One would think there are other regulation being broken here.

  15. Thomas v

    I to have been a Vonage subscriber for around five years now and in the beginning I was using a low bandwidth DSL connection and was used to drop packets and conversation but over the past 15 months I have been on ComCast and have not experienced this packet drop.

    I can not say that now because over the past two months I have “sometimes unusable” Vonage service with all the packet drop on the upstream side as I can here the other person but they can not here me. I have spent several hours on my cell phone with Vonage and have made some adjustments such as port forwarding my router to the VOIP router, and most recently I upgraded my Firmware on my WRT54G to the “Open WRT” firm ware which enabled quite a few more option like (QoS) which is a must for the VOIP being on the Internet alot – QoS allows me to make sure a certain amount of bandwidth is available to my Vonage Service even if I am downloading something.

    Needless to say my Vonage Service has become pretty troublesome and I have complained to ComCast not sure where that will go.

    Conclusion with all the “hacking” I have had to do in order to recover some of my service by no means is it like it use to be and I am convinced my ISP has implemented some sort of traffic management that is causing this recent problem.


  16. Are you sure the secondary site you tried was slower? I have comcast residential with 18Mbps down and 2mbps up. I’d be interested to know what your bandwidth report was during one of those period of bad vonage quality.

  17. I’ve been a Comcast internet customer or over 5 years. I’ve been a Vonage customer for over 3 years. About 6 months ago I upgraded my Comcast service from “residential” to “business internet” (which increased both my upstream and downstream bandwidth). is currently reporting that I’m getting over 6.5Mbps downstream and over 1.4 Mbps upstream bandwidth. But at this very moment (and for the past 5 days), my Vonage service from this location has been unusable – all that gets through are bits and pieces of my voice with a lot of static.

    To test my phone, I connected a different phone at the problematic location. No improvement. To test my Vonage phone number (I have two phone numbers configured on my Vonage box), I tried both lines. No difference, both are bad. To test my Vonage box, I connected it in a different location about 80 miles away (but still through Comcast). At this alternate location there were no issues with voice call quality, even though the Comcast service is the slower residential service and not business internet.

    Conclusion: At my primary location, Comcast is definitely doing something that negatively impacts Vonage call quality on at least a portion of their network.

  18. Frank Chen

    I’ve recently had problems with both Vonage (after 4 years with no problems) and magicJack over Comcast.

    Periodically, bandwidth will drop to near 0, resulting in 20- to 30-second silent times during my calls. I thought it was Vonage’s problem so I tried magicJack — exact same behavior.

    Comcast claims it’s “network congestion in my neighborhood”. That seems extremely unlikely to me — not that many neighbors and why would it be so periodic?

  19. There is no measurable effect, so far. No VOIP users have complained as far as I can see.

    A few Vonage users on Comcast appear to have commented here and there; but, Vonage often sucks.

    I’ve used Skype for years on Comcast without a whisper of a problem. I video conference with a friend the other side of the country several times a week and he uses Skype or Google Voice with no problems. His Vonage drops dead every 6-8 weeks. He’s also on Comcast.

    So far – and I stress this is short term peering around the Web – I see nothing but a fishing trip.