Internet Service Provider(ISP): Is a company that provides Internet access to customers. ISPs are responsible for providing a connection to the Internet for homes and businesses etc..
Internet Backbone(IB): Is a very high-speed data transmission line that provides networking facilities to relatively small but high-speed Internet service providers all around the world.
Domain Name System(DNS): Is a server that is specifically used for matching website hostname to their corresponding IP addresses.The DNS Server contains database of public IP addresses & their corresponding domain name.