IP Address Lookup Times
IP Address Lookup (DNS)
The time it takes an ISPs equipment to find out the numerical version of the IP address of a page you request can be an important factor in the time it takes to download a webpage. All webpages and associated files not only have a readable name like www.stuff.co.nz, but also have an IP address for the computers to read like 220.127.116.11. Technologies are available to minimise the number of lookups, but not all webpages utilise these technologies.
Many older style pages require a new lookup for every part of the page, if the page has 100 files, then this can become a significant time if the lookup time is longer than say 50ms, ie 100 x 50ms is 5 seconds.
We have looked at the relationship between IP Address Lookup time and regional Location or Distance from the DSLAM.
This chart shows a distinct pattern of DNS lookup times increasing by logical distance from the DNS Server, most often located in Auckland. Some ISPs have recently built DNS servers in other cities to improve performance, this can be seen in the chart.