June 13, 2013

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Explained: Why Internet Traffic Slows At Times

Used with Permission from iStock

Occasionally, Internet users experience a lagging video game or a stuttering YouTube video. We do our best to minimize buffering and other slowdowns at Time Warner Cable, but this is normal for broadband users at any Internet service provider, at least some of the time. The reasons, as we’ll explain below, have to do with the way the Internet works.

A small subset of our customers, however, seem to think we are intentionally degrading their service.

If I were to sum up these kinds of complaints, it would go something like this: “Hulu and YouTube wouldn’t intentionally degrade their services and provide a subpar experience, but for some reason, it makes total sense that Time Warner Cable would by throttling customers’ traffic.”

Our standard response has been a simple, “We don’t throttle traffic.” That’s because we don’t. Some people want us to elaborate, so here goes:

The Internet is not as simple as one wire connecting a website’s servers to a customer’s home. Traffic originates in countless places, heading toward billions of end-user destinations. Each network that carries web traffic is itself a collection of a number of complicated technological and business relationships. As traffic flows from one area of the Internet to another, it passes through this network of technologies, agreements, and protocols and culminates in each particular user experience.

We’ve invested billions of dollars to ensure that our networks deliver the best possible experience regardless of the source or nature of the traffic. However, the traffic only moves as fast as the weakest link. And when traffic travels across multiple networks, each with its own relationships, slowdowns and other problems can and do occur.

Because the Internet is a network made of networks, there is no central control over the Internet’s entire performance as a whole. No single participant in this ecosystem can guarantee performance to end users at a particular level of service.

TCP/IP transmission – the basic protocol used on the Internet – is designed to deal with the congestion and other problems that inevitably will occur on interconnected networks of this nature by dropping and reordering packets of data, and taking other similar steps. Performance can also vary depending on the number of users in a household at a particular moment, the number and types of simultaneous uses they are pursuing, the time of day, and network congestion.

At Time Warner Cable, we interconnect with a diverse portfolio of different networks to get traffic on and off of our network as effectively and efficiently as possible. But each network makes its own decisions on how to best send or receive traffic. Each network provider has its own level of investment and service commitments, and so quality levels can vary greatly among them.

Websites and other content providers make their own arrangements about how to get traffic to and from the Internet. And each participant in the Internet ecosystem makes its own decision about the formats and equipment to use, and each has its own budget. So the levels of quality vary greatly at the source as well as the network level.

Also, some, but not all, online video providers have the resources to store copies, or caches, of their videos on servers that are a part of a Content Delivery Network, or CDN. When a user clicks on a link to a particular video, the Internet provider can quickly determine where the nearest cached copy of the video is on the CDN and deliver it. More popular videos will have more cached copies, with better performance, while less popular videos may be stored in fewer, further places.

This is one of the reasons why “Gangnam Style,” when coming from a major provider, tends to load faster and play more smoothly than some ponytail guy’s video of himself covering Rush on the dulcimer.

Delivery of video and other data over the Internet is a complex matter with many, many variables contributing to each particular end-user experience. But we can assure you that, at Time Warner Cable, we don’t throttle traffic. We do our absolute best to provide high-quality Internet service, with a variety of speed tiers to address customers’ particular needs and pocketbook, regardless of the source or type of traffic.


  1. Steven D's reply

    So what’s the deal with Netflix “Super HD”?
    I want that on my TWC connection.

  2. Jason Schwartz's reply


    I guess TWC didn’t partner with Netflix and their CDN. Interesting concept of partnering to deliver competing content. On the one hand, TWC is a video distribution service. To gain full utilization of their infrastructure, they also deliver data over that cable in the form of TWC “The ISP”. This was acceptable and beneficial to TWC before services like Netflix and Hulu came along.

    Now with these so-called comptetitors, in theory, that would be like allowing Cableivision to deliver video over TWC’s network.

  3. Sean M's reply

    Sorry , Jeff
    I’d still watch the RUSH video over gag-ham style anyday….

  4. Mike's reply

    Good explanation, but it really should be on a twc.com ‘FAQ Details’ page for the 99% of the non-techies who don’t read this blog.

    Topic for future post – how about some details on the ‘video-only modem’ for TWC-TV mentioned in the newsletter in 4 pt type :-(. If it creates just another Wi-Fi network, we should have some info to assure that it can work around the other non-TWC SSIDs ‘floating around’. TIA!

  5. mike's reply

    you don’t do throttling. that’s funny how come when i use a vpn i can watch a 1080p youtube vid no prob. turn the vpn off i can barely watch it at 480p same vids. don’t tell me its your infrastructure you can do what you want. that infrastructure is subsidized by the gov. we the tax payers deserve better faster internet. it is a sad day when a third world country is getting comparable internet speeds.

  6. Slappi's reply

    I call BS.

    I’m actually able to confirm that internet speeds are much faster at work, granted using a different provider, than they are at home. I feel as though I should be receiving top-notch service from Time Warner, but our speeds have declined dramatically over the past month.

    Also, explain how the different speed levels of internet service are provided? Is that not throttling internet speeds for those who don’t purchase the very best package?

    What says Time Warner isn’t throttling those with lesser packages?

    And “coincidentally”, our internet speeds have dropped over the past month, and what did I find in my Time Warner bill this month? A flyer to pay more and get faster internet speeds. Interesting, eh?

  7. Eric Nay's reply

    It is a simple equation. We pay you for service. You choose not to follow that rule, and instead sell access to us to the largest internet sites. If they don’t pay you then you limit the speeds we can access them at.

    As customers, we want Netflix. You want to take the TV business for yourself, so you have no interest in answering our demands. It is a really simple but defective paradigm.

    As long as your business model relies upon extorting money from both sides and creating customer dissatisfaction, then your customers will revolt at every chance. It is just that simple.

  8. John's reply

    Based on my tests and observations, Time Warner Cable’s inability to stream videos with the best quality or faster than other providers is caused by higher levels of jitter (mean deviation in round trip times) associated with their network when compared to other major ISPs. This is why sometimes you will be watching an online HD video and the quality will change back and forth from standard definition, even though you may have 100 Mbps of available bandwidth. High deviation in round trip times cause data transfers to have an unreliable rate of bandwidth.

  9. Lana's reply

    If that’s true then how come everyday from 7pm-midnight the service in western ny is crap. I can’t load anything. I’ve actually done speedtest for a whole day every 4 hours and the quality goes from okay to complete crap. When it’s just me using the computer to go to my school’s website to upload a paper. When Google Chrome comes to town lets see if TWC is singing the same tune.

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