2. What is the difference between network architecture and application architecture?

First, what is an architecture? Simply, an architecture is a representation of the parts of a thing, the relationships between those parts, and the attributes of the parts and relationships. The term "application", in the context of computers, is primarily used to mean an assemblage, of software instructions and data, operating as a system, to achieve a specified output. So an applicaton architecture is the representation of the application's software, data, and output parts, the software, data, and output relationships, and the software, data, output and relationship attributes. The term "network", in the context of computers, in primarily used to mean an assemblage, of devices and services, operating as a system to provide communication capabilities for person, group, and application users of the network. So a network architecture is the representation of the network's devices, services, and users, their relationships, and the the device, service, user, and relationship attributes. Architectures can be represented graphically and textually. Graphical representations of architecture take the form of "directed-labeled-graphs" (DLG), which are "labeled node-arrow-node" diagrams. Graphical communication network models, Process models, data models, metamodels, and ontologies use DLG constructs as a primary tool. Modeling, in general, uses DLG as its primary tool. Textual representations of architecture take the form of populated multidimensional matrices such as pivot tables, OLAP cubes, metadata repository metamodels, and ontologies. Advanced modeling can take place using integrated graphical and textual representation technologies.