Yes all the four parts is very important in absolute URL. Because if any one of the four parts is missing then the browser would not able to link to the specific file.

Absolute URL is the complete address of a document on the Internet. Absolute URL contains all the information that are required to find the files on the lnternet.

Where, http - protocol
www.cms.tn.gov.in - host name/domain name sites/default/files/press_release - folders Pr070119a.jPg - file name.

The number of address that can be formed in IPv6 is 2¹²⁸ In IPv6 address, the 128 bits are divided into eight 16-bits blocks. Each block is then changed into 4-digit Hexadecimal numbers separated by colon symbols.
Eg. 2001:0000:32313:DFE1:0063:0000:FDFB.

Total number of address is determined by the number of bits that the protocol use. If the protocol uses 'n' bits, then the address space of the protocol would be 2ⁿ. So the number of address that can be formed in IPv4 is 2³². [n = 32 bit].

IP address is simply the logical address in the network layer. It is also used to find the host system in the whole network.

While typing a web address, eg. wvw.tnschool.gov.in, DNS translates it into a machine friendly IP address (for example 35.173.69.207 is the IP for www.tnschools.in) and directs your Internet connection to the correct website.

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

(i) Domain Name System is a client server application.
(ii) A host system need to map domain name to IP address or vice versa according to the call and that work is done by resolver .
(iii) Resolver either asks server to provide information about IP address.
(iv)  If it doesn't find any information, then it sends the request to other servers and so on.
(v)  Once the resolver receives the mapping, it checks whether it is an error or resolution (mapping) and provides result according to that

(i) Country domain uses 2-character Country abbreviation according to country.
(ii)  For e.g., google.in - for INDIA, Google's for US. Some of the Domain Name and their meaning

(i)  Flat name space is where the name is assigned to the IP address.
(ii)  They do not have any specific structure .
(iii) In this flat namespace, some meaningful names are been given to IP address for accessing.
Disadvantage:
(i)  Flat name Space cannot be used in large system. Because they need to be accessed and controlled centrally to avoid ambiguity and redundancy.
(ii)  But it is difficult in flat name system. To avoid this major disadvantage hierarchical name space is used in large.

(i) URL is made up four parts-protocols, hostname, folder name and file name. .
(ii) Each part has its own specific functions. Depending on the applications, additional information can be added to the URL but the common and fundamental URL consists of these four parts.
a. Protocol
b. Domain name/Hostname
c. Folders
d. The file name with extension