Nintendo Entertainment System
The answer would be the TCP/IP Application Layer.
DescriptionNetwork topology is the arrangement of the elements of a communication network. Network topology can be used to define or describe the arrangement of various types of telecommunication networks, including command and control radio networks, industrial fieldbusses and computer networks.
21%4 is 1.
21-4=17
17-4=13
13-4=9
9-4=5
5-4=1