What is number addresing ? And dns also coming in the number addressing
Answers
To identify hosts, IP addresses (especially IPv6 addresses) are cumbersome for humans to use and remember. The Internet supports the use of host names to identify hosts, both clients and servers. In order to be used by protocols such as TCP and IP, host names are converted into IP addresses using a process known as name resolution. There are different forms of name resolution in the Internet, but the most prevalent and important one uses a distributed database system known as the Domain Name System (DNS). DNS runs as an application on the Internet, using IPv4 or IPv6 (or both). For scalability, DNS names are hierarchical, as are the servers that support name resolution.
DNS is a distributed client/server networked database used by TCP/IP applications to map between host names and IP addresses (and vice versa), to provide capabilities like electronic mail routing information and service naming. The DNS provides the protocol that allows clients and servers to communicate with each other and also a protocol for allowing servers to exchange information. [p511]
From an application’s point of view, access to the DNS is through an application library called a resolver. An application must convert a host name to an IPv4 and/or IPv6 address before it can ask TCP to open a connection or send a unicast datagram using UDP. The TCP and IP protocol implementations know nothing about the DNS; they operate only with the addresses.
This chapter covers:
How the names in DNS are set up
How resolvers and servers communicate using the Internet protocols (mainly UDP)
Some other resolution mechanisms used in Internet environments.