What is Domain Name System?
– In inter-networking, there is a requirement of associating various domain names of the participating entities with a large amount of diverse information.
– This requirement is fulfilled by a distributed naming system for computers as well as other resources bearing a connection with a private network or the internet.
– This system is commonly known as the DNS or Domain Name System.
– Its basic purpose is the translation of the domain names that convey a meaning to the user into numerical IP addresses.
– These addresses are required for locating the computer services and resources over a network throughout the world.
What are characteristics of Domain Name System
In this article we discuss about the characteristics of the domain name system.
1. The first characteristic feature of the domain name system is its hierarchical nature.
– It provides a distributed redirection service based up on keywords accepted worldwide.
– Thus, it is also counted as a vital part of the internet’s functionality.
– A tree of domain names is what that constitutes domain name space.
– Each node in the tree possesses either no or many resource records holding information about the domain name.
– The tree begins at the root zone and then sub divides.
2. Updating the DNS does not take much time, it’s very quick.
– This allows a service to change its location without affecting the users who are accessing it through the network.
– For users the host name does not change.
– The users get an advantage of this since they can use the same URLs and email addresses without having to worry about how the services will be actually located.
– The responsibility of assigning the domain names as well as mapping the names to corresponding IP addresses is distributed to dedicated servers usually called as the authoritative name servers.
– These servers hold responsibility of their particular domains.
4. Fault Tolerant:
– The DNS because of its highly distributive nature has a high fault tolerance capacity.
– This has also eliminated the need of having a central server that otherwise would have be continuously updated and consulted.
– A number of domain name registrars hold the responsibility of updating and maintenance of the master records.
– The domains whenever required can be moved from one registrar to another.
6. The technical functionality of the database service are specified by the DNS. It also defines the DNS protocol which is also a part of the IP suite.
7. Translation services:
– There are two namespaces provided by the internet namely IP address spaces and the domain name hierarchy.
– The DNS takes case of the latter and provides translation services among the two.
8. DNS itself is implemented through a communication protocol and the internet name servers.
9. Domain name syntax:
– One or more labels together constitute the domain name.
– The top level domain is conveyed by the right – most label.
– The maximum length of a domain name does not exceed 253 characters.
– However, practically shorter limits are set for the domain registries.
10. Address resolution mechanism:
– The appropriate domain name servers are determined by the domain name resolver.
– These servers are responsible for questioning a sequence of queries.
– An initial cache containing the addresses of the root name servers is set up for every network host.
– The files are regularly updated by the administrator.
– Two queries are made: One to the root server for finding the authoritative server of the top – level domain and the other to the TLD server for obtaining the address of the authoritative server for second–level domain.
– These steps are repeated until the IP address of the host is obtained.
11. Less burden:
– The simplicity of the operating mechanism often burden ups the root servers.
– Root servers are critical to the functioning of the whole system.
– To avoid this caching is used in the servers so that they face very little traffic.
12. Recursive and caching name server:
– All the DNS queries start with the recursive queries at its root zone.
– This is not mandatory but it increases the efficiency of the design and operation of the system.