=OSI Model and Transmission Path=
 A.OSI 7-Layer Model
 B.Signals and Network Media
 C.Data Link Layer
 D.Bridges and Repeaters
 E.ARP and ARP tables
 F.Topologies and Access Methods
  Related Items
 A-1 What is the OSI model?
 A-2 OSI 7-Layer Model and the role of each layer
 A-3 Function modules and Header Additions
 A-4 Concepts of Data transmission
 A-5 Names and IP Addresses
 A-6 Comparison with TCP/IP
 A-7 Evaluation points of network equipment

 A-5 Names and IP Addresses

The relationship of names and IP addresses shown here is misunderstood in many cases, although it is often used.
A string such as "www.foocrane.jp" is called a name. Remember that the network communication with only name is basically impossible (data transmission and name are unrelated to each other).

In Web browsers, the format of www.foocrane.jp is used for the connection. However, because only the following two addresses are used to identify the communication partner: MAC Address (the data link layer) and IP address (the network layer), the delivery with the string "www.foocrane.jp" is impossible in networks.
To connect to a network with a name, it is converted into the IP address by Name Server.
When seeing a Web page, the name is not directly used. The IP Address of WWW Server managing the Web page to be seen is inquired to Name Server and the communication is carried out based on the IP Address gotten.
This is shown in the following figure.
Figure A-5-1 Relationship of name and IP Address