In its latest effort to accelerate the rate at which Web pages load for users, Google Dec. 3 launched its own free Domain Name System, Google Public DNS, into a crowded market that includes several providers already.
A Domain Name System is basically a hierarchical naming system for computers or any resource connected to the Internet. However, because it is not something the average Web user sees on the surface, it helps to think of the DNS as a sort of phone book for the Internet because it translates computer host names into IP addresses. Prem Ramaswami, product manager for Google Public DNS, explained:
""Most of us aren't familiar with DNS because it's often handled automatically by our Internet Service Provider (ISP), but it provides an essential function for the Web. You could think of it as the switchboard of the Internet, converting easy-to-remember domain names-e.g., www.google.com-into the unique Internet Protocol (IP) numbers-e.g., 126.96.36.199-that computers use to communicate with one another.""
Google Public DNS is the company's stab at making Web pages load faster at a time when millions of users are accessing the Web several times a day, triggering multiple DNS requests. This can bog down the Web page rendering process, which means users are sitting at their computers, waiting to view Web pages.
Ramaswami told eWEEK that Google Public DNS is focused on improving DNS speed, security and the validity of results. He explained how it works: When a user loads a Web page, that triggers a DNS query to the ISP, which in turn has to go out across the Web to get the correct answer. For example, when a user searches for mail.google.com, his or her ISP resolver will go ask the dot-com servers what Google.com's server is, then go ask Google.com's server what the IP address is for mail.google.com and return that to the Web user.
This process takes longer, Ramaswami noted, because the DNS has to crawl the Web and ask several servers to get the correct answer. Google Public DNS issues DNS queries constantly, regardless of whether people have queried the DNS. This means Google always has the query info in its cache. Each question comes with a "time to live." Before the time limit of, say 300 seconds, expires, Google will ask the question for a big range of domain names.