I am trying to check my understanding about the ways of communication in IP networks. I would classify the ways of communication in IP networks into three generic types:

  1. The source requests name resolution of the destination using DNS service.
  2. TCP handshaking.
  3. UDP.

Can someone validate my reasoning?


Name resolution is an application-layer protocol/function, and it can happen with protocols other than IP; it really has nothing to do with IP.

TCP and UDP are layer-4 protocols, while IP is a layer-3 protocol. Theoretically, TCP and UDP could be used on protocols other than IP, but I am unaware of any such implementations.

IP has a field in the header to tell IP to which upper-layer protocol it should send its payload. IPv4 uses the Protocol field , and IPv6 uses the Next Header field for this. There are many IANA registered protocols which use IP.


Dns name resolution (DNS)

Hence computer always goes with numbers , but it's quit difficult remember numbers by humans to overcome this issue DNS concept is introduced

Dns maps domain names to IP address

Example.com => 211.X.X.X

There are two types of DNS querries

  1. Recursive querry
  2. iterative querry

=> Recursive querry reslove domain names within local DNS server

=> Iterative querry reslove domain names with help of global dns like

==> ISP name server ==> root dns server==> top level servers (TLD) dns servers ==> authoritative dns servers .

authoritative dns servers are dns server maintenaned by individuals organization as per there business requirements.

TCP handshake

Hence TCP is reliable protocol . TCP handshake should be completed successfully before sending actually data from client -- > servers


User datargram protocols is non reliable protocols . Mainly used for DNS traffic , voice traffic .


--> when user tries to access webpage using URL, request for webpage go to the DNS for Ip resolution, after getting Ip request go through all layers of OSI and reach to the related server and server respond to that request. TCP or UDP is totally depends on the request you are making. TCP and UDP is for service port authentication in networking. after that IP address works to reach out servers.

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