http://arstechnica.com/information-technology/2014/02/netflix-slow-on-verizon-or-comcast-a-vpn-might-speed-up-that-video/
Netflix slow on Verizon or Comcast? A VPN might speed up that video No VPN for me, thank you. Comcast Since reporting on Netflix data that shows months-long declines in streaming performance on Verizon and Comcast, we've heard from several readers who say they've eliminated video problems by using VPN services. "Netflix on Comcast tanked for us in the past month or two," one commenter wrote. "We would spend more time buffering than actually watching video. Once we set up a VPN with UnblockUs it magically went away." Another reader sent us bandwidth statistics from his home that compared traffic on Comcast to traffic over a VPN, saying the poor Comcast performance proves that "they throttle Netflix heavily." Similar accusations have been leveled against Verizon. No one has actually shown beyond a shadow of a doubt that ISPs directly throttle Netflix traffic. Throttling may be legal in the US now that Verizon has convinced a court to strike down net neutrality rules, and Netflix has criticized ISPs, but it hasn't gone so far as to allege throttling. Netflix performance does vary by ISP, but we can't rule out the possibility that Netflix's own practices are causing bad outcomes for consumers. It's also possible that no one is doing anything particularly nefarious. What's clear is that somewhere in the path from Netflix servers to consumers' homes, there is congestion. It's also clear that some people have improved their own streaming video by using VPNs (virtual private networks) or third-party DNS (Domain Name System) services. (UnblockUs, mentioned above, is not technically a VPN service but it achieves a similar effect by changing your DNS settings.) There's no guarantee that using a VPN will improve things--it could even make them worse. But if you're desperate, it may be worth a try. Routing around congestion Sandvine cofounder and CTO Don Bowman talked to Ars this week about why VPN and DNS services can help relieve congestion for certain users. He also talked about the types of shady tactics both video streaming providers and ISPs could employ in their ongoing battles and how that could harm home Internet users. Sandvine is a maker of equipment that helps consumer broadband providers manage network congestion, a controversial practice several years back when it came to Comcast's use of Sandvine products to limit peer-to-peer file sharing traffic, which led to a 2008 agreement settling the matter between Comcast and BitTorrent. Sandvine also publishes research on which applications drive growth in Internet usage, showing that Netflix and YouTube together account for more than half of peak downstream traffic on North American fixed networks. VPN services route an Internet user's traffic through data centers in different locations and are usually sold to people who seek anonymity or to evade country-specific blocks (such as video content blocked in certain countries). As a side effect, a VPN may route your traffic away from congested servers and links that would normally serve up video to your home. Netflix and YouTube store video caches in many locations, and data can take multiple paths to its final destination. "Imagine you're in the US and that you are on a carrier that existed in multiple states and time zones, you can VPN to the West Coast from the East Coast and end up getting the idle servers that are there, just sitting and waiting for people to get out of school and off work and so on," Bowman said. BTGuard and Private Tunnel are examples of VPN services. If you consistently get better performance with a VPN than without, it could be a sign of a "systematic dispute between vendors upstream." In the past, Verizon and Comcast have each had disputes with bandwidth providers over whether the ISPs should be paid to carry Netflix traffic. These disputes can lead to the links between networks not being upgraded quickly enough. This affects all traffic, but is more noticeable for bandwidth-hungry streaming video. "If a VPN consistently behaves better, it's proof that there is something along the path that doesn't have enough capacity," Bowman said. "It might be a link [between providers] or it might be a server. There may not be enough servers in the server farm, there may not be enough capacity between the two carriers." This would not be proof that Verizon or Comcast is throttling Netflix or any specific application. "The only way you could draw that conclusion is if you guaranteed [traffic] came from the same path and server but that somehow the VPN made it look different," Bowman said. "If you could VPN to the same server you were getting the streaming from, using exactly the same path and then it behaves better, that would be pretty conclusive proof." It's important to know that Netflix and your ISP aren't the only two companies responsible for carrying traffic. Bits have to travel across numerous networks, and problems could crop up in any of them. "Streaming content exists on a set of CDN (content delivery network) providers from more than one company, and they in turn have many servers in each location, and they have multiple locations, and each of those locations has a set of intermediate ISPs which connect to a set of intermediate ISPs which connect to the eyeball ISP you're on," Bowman said. "It's very difficult for even networking professionals who are in those locations to know how a packet will flow." CDNs can take multiple paths to a consumer ISP and will hit transit networks on the way there. The receiver of content is responsible for showing how it can be reached, while the sender is responsible for how it reaches the endpoint when there are multiple choices, Bowman explained. Using a VPN can force the sender to make different choices than it otherwise would. Sandvine research suggests that there are generally no systemic problems within consumer ISP networks--it's the interconnects between networks where trouble arises. Enlarge / The Internet--it's... complicated. Wikimedia Commons Using a VPN takes your traffic away from the shortest path by distance, but may be faster in cases when the path would otherwise be congested. Networks generally aren't intelligent enough to automatically route around congestion. "A network is based around packet switching, and every packet is treated independently," Bowman said. "At each location it's got a set of ways to get to its next location. It doesn't know that two hops down it gets busy." In the future, it may be easier to pinpoint the source of problems. Speed test tools from Netflix and Google today show averages across wide swaths of users. Bowman said he'd like to see more advanced tools that benchmark the interconnections between specific network providers. You're rolling the dice by using a VPN, betting that you might get a faster path. That bet may backfire. "In general it makes things worse for the user," he said. "There's a reason they're trying to do this optimization, to give you the best experience, and you're breaking it." What Bowman said about VPN is also roughly true of DNS services. Using a standalone DNS provider instead of your ISP's DNS can sometimes change where your streaming data comes from. "You're effectively lying to their system and pretending to be somewhere else," he said. "It's exactly the same effect, it's achieved differently, you don't actually use a VPN or a tunnel." Streaming services may use DNS-based geo-location to figure out an optimal path to send traffic. Tricking the geo-location system can result in the data being sent from a different location and along a different path. Google DNS and similar services like OpenDNS also promise faster Web browsing speed as a result of reducing bottlenecks related to DNS lookups. Who's to blame for slow video? Maybe the ISP, maybe the video provider Netflix's speed test data is just an average, so it doesn't reveal anything specific about particular networks. Google is in the process of rolling out a more extensive speed test tool for YouTube. The YouTube data will show what percentage of consumers are able to get a high-definition stream at any given time in any given city. YouTube speed results for Rogers in Waterloo, Ontario. Results are not available in all locations yet. Sandvine The months-long trend of performance on Verizon and Comcast getting worse on Netflix does indicate that there is "congestion at a B-to-B relationship upstream," Bowman said. "Whether it is consumer ISP to their providers or content providers purposely doing this I don't know." Netflix did not make any comment in response to our questions. Netflix's senior leadership reportedly has said the company does not believe its service is being throttled by Verizon or other ISPs. JP Morgan analyst Doug Anmuth, who had talked to Netflix CEO Reed Hastings and CFO David Wells, wrote that "Netflix does not seem overly concerned regarding Net Neutrality, and continues to believe that violations would be escalated quickly. Netflix also indicated that it has no evidence or belief that its service is being throttled." ISPs that offer their own video services do have incentives to harm Netflix and YouTube traffic. If your ISP is actively throttling your traffic, a VPN may not do any good. The ISP controls the last mile to your home, so even if the VPN hides what type of traffic is being sent, the ISP could make your life miserable by slowing down everything. The ISP could also use deep packet inspection to figure out that you're using a VPN. Depending on your terms of service, your ISP may use deep packet inspection or application filtering to de-prioritize or block VPN traffic. Verizon has suggested that Netflix is the cause of customer problems. "How the Internet works can be complicated, and consumers should be aware of the fact that the integrity of their home Internet connection is only a portion of the streaming video quality equation," Verizon told Ars Monday. "If their broadband connection is functioning correctly, the source of their frustration and the content they wish to see may be one and the same." In previous stories, we've discussed how ISPs like Verizon and Comcast can harm video quality by failing to upgrade links with other network operators. Verizon has argued that Netflix's bandwidth providers, like Cogent, should compensate Verizon for accepting its traffic instead of continuing the companies' traditionally free peering arrangements. Netflix also offers to peer directly with residential ISPs with its Open Connect CDN, eliminating the middleman, but providers such as Verizon, Comcast, and Time Warner Cable have refused. Verizon declined to talk to Ars about its peering arrangements. Peering negotiations and agreements are generally secret, and it's rare that we know what tactics specific companies use against each other to gain leverage. But the ISPs aren't the only ones who have weapons at their disposal. Bowman explained that Netflix, if it chose to, could make life difficult for ISPs in an attempt to force them into peering arrangements that could reduce Netflix's costs. Maximize the pain There's actually a "peering playbook" written by consulting firm DrPeering International, with strategies for forcing ISPs into free peering agreements. One tactic is to manipulate traffic in such a way that peering becomes the most cost-effective option for your opponents at the negotiating table. "They recommend strategically choosing paths to maximize the costs to the person you're trying to force to peer with you," Bowman said. How would it work? "Hypothetically, let's say I know the ISP I'm going to pick on this month, and I know there's three different ways into their network. One of them they pay a dollar for, one they pay $10 for, and one they pay $100 for. So I just switch all my traffic to the $100 one until they cry and then I say, 'ok, I'll come to your door and let's just do it for free.'" Enlarge / The peering playbook is titled "The Art of Peering" and borrows tactics from Sun Tzu's Art of War. Nuno Barreto Similarly, an ISP may have "three links that are each 10 gigabit. They're expecting that I'll send my traffic equally on all three links. What I'll do instead is on Monday I'll send on link 1 and on Tuesday I'll send on link 2, and then congestion will appear and subscribers will have a bad experience." The ISP would be forced to upgrade each of the links, even though only one of them would be used to capacity on any given day. >From the video streaming provider's point of view, "I'm forcing them to spend >a lot of money, they're stranding their capital, eventually they'll come to my >door to negotiate. That's what the peering playbook talks about." "Without a doubt there is some streaming company doing that today. I just couldn't say that it's anyone specific because I don't have information to show it," he said. Netflix wants to peer directly with ISPs and put its video caches inside the ISP data centers. The offer is "free," but ISPs would have to host equipment dedicated to Netflix, letting Netflix save money on transit fees. Some ISPs believe this is a win-win on both sides and for consumers, but ISPs who think otherwise have a valid point, Bowman said. "If someone comes to you and says, 'hey I'm big, I want differentiated service, I'd like to move close to your consumers, so can you please make 40 inches of space and 5,000 watts of power available at 100 sites, thanks very much,' you would normally say, 'I'm in the business of selling that--here's my price list." -- You received this message because you are subscribed to the Google Groups "The Unique Geek" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/theuniquegeek. For more options, visit https://groups.google.com/groups/opt_out.
