Internet Corporation for Assigned Name and Numbers, Non - profit organization which regulates an Internet.

Domain Name System (DNS) maintains all the directory of domain names/host names and help us to access the websites using the domain/host names.

Domain Name space is an entire collection Domains, Sub domains and Zones

Domain Name	Meaning
com	Commerical Organistion
edu	Education Institutions
gov	Government (US)
mil	Military groups

1. Root element is present at the top most level (ie) level 0.
2. Next level to the root element is node (children of root element)
3. Each node in the tree has a label and a domain name.

(i) The resolver is a program which is responsible for initiating the translation of a domain name into an IP address.
(ii) Since a resolver is stored in the host. There is no need of any protocol to form a connection between the resolver and the user program.

Zone is a group of contiguous domains and subdomains. If the zone has a single domain, then zone and domain are the same.

Domain is a sub tree in domain name space tree structure.

The URL is divided into 2 types
(i) Absolute URL
(ii) Relative URL

(i) www.tn.gov.in
(ii) www.google.com
(iii) www.Quora.com
(iv) www.wikipedia.org

URL (Uniform Resource Locator) is the address of a document on the Internet. URL is made up of four parts: protocols, hostname, folder name and file name. Each part has its own specified functions.

The types of IP address
(i) IPv4 Address and
(ii) IPv6 Address

Internet Protocol (IP) address is simply the logical address in the network layer. IP address is also used to find the host system in the whole network.

Domain Name	Meaning
TLD	Top Level Domains
ccTLD	country code Top Level Domains.
gTLD	generic Top Level Domains.
IDN ccTLD	internationalised country code top-level domains.