According to Ping reports my web browser is looking up DNS information in 180ms to connect my domain. I registered that domain name from godaddy.com. At the same time it takes 10ms for connecting to another domain. It is bought from bigrock.com. As my uncle said, all the domains are registered in networksolutions. Then why is this much time difference?
The ping time is how long it takes for a packet to travel from your computer to the domain you are pinging.
So if I ping facebook from san francisco, and hit their server in palo alto, then the ping time will be short. If i ping them from japan, the ping time will be higher because it takes time for those packets to travel. (this is a bad example since facebook has servers all over the world, and closest server usually is the one you get).
As for DNS. A dns simply translates a name to address. So facebook translates to its ip addresses. DNS holds different types of records for different server, services, etc. When you ping a site by its name, versus ip.
Ping facebook.com vs Ping 126.96.36.199
Then the dns server looks up the ip address first, and pings that. That lookup of ip address information usually takes a small period of time. This is usually called fetching. Your computer will cache this information so the next time around the trip is not required. This cache is set by the DNS ttl value. But your DNS host (such as google public DNS) will also cache this information in an effort to make the web faster. So if you have comcast, att or google as your dns, each will cache the request.
If your goal is to have a quick site here are some items to consider. 1. DNS hosting is not a big expense in page speed. If you are super worried about DNS speed then pay for premium dns services such as Godaddy's or Zerigo (which has a lot of settings).
Although performance is not something that totally depends on the money you spend, money can usually solve most performance problems. Adding resources, cdn, etc, will all speed up your site, but it can get expensive if your site is not built for speed. In other words, performance should not be an afterthought, but dont spend too much time worrying about it where your product or site launch is delayed. Its something you can continually tweak to improve, and with profits put more money behind.