t for the IP address of the nameserver that has authority over the tcic.com domain. The IP address that is returned at this point will be one of the addresses that the domain owner entered when registering the domain with Network Solutions or one of the other registrars. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Function of GPRS Elements Chapter 4 Now that your local nameserver knows where to find the nameserver for the target machine, it asks that nameserver for the IP address of the target. The target's nameserver returns that information, as well as a time-to-live (TTL)-the amount of time that your local nameserver should store the IP address it has received. (This time is generally set fairly low-a matter of days or hours.) Once your local nameserver has this information, it returns the information to your computer, and you are able to connect to the target machine. DNS uses client/server architecture to maintain and distribute host- names and IP addresses on networks ranging from small Local Area Net- works (LANs) to the entire Internet. Under DNS, the Internet consists of a hierarchy of domains. This hierarchy, referred to as the domain name space, is organized as an inverted tree radiating from a single root, much like a UNIX file system. Domain Name Space The root domain (.) is the base of the tree. Final attempts to resolve names to IP addresses take place here if lower-level servers do not have the requested data. The root domain is usually omitted from domain names. Usually, this doesn't affect looking up IP addresses; however, the period (.) is usually vital when configuring DNS data. Domains Internet uses naming convention called domain names. The domain name consists of two or more parts separated with a period (.). It starts from the least significant domain and ends up to most significant domain or top-level domain. Thi