When I first read that some Apple TV users were seeing significant speed-ups when they start using a local ISP Domain Name System (DNS) server instead of continuing to use one of the universal DNS services, such as OpenDNS, DNS Advantage,or Google Public DNS, my first thought was, “That’s wrong.”
I understand their logic that “When millions of users all tap into the same DNS server addresses to resolve domain names, as Google DNS does by design, Akamai and other CDNs [Content Delivery Networks] route content to those users along the same path, preventing the network from working optimally.” The problem is that this isn’t really how the big DNS networks and CDNs work these days.
For starters, this proposed fix starts with the notion that your ISP has a local DNS, hence you’ll get a better, less-crowded route for your video. You probably don’t have a truly local DNS though. The national ISPs like Comcast. Verizon, or ATT, just like the universal DNS services, spread their DNS servers around. In this case, their DNS server isn’t going to be much ‘closer,’ in terms of network distance than Google’s.