Network architecture

Network architecture refers to the layout of the network, consisting of the hardware, software, connectivity, communication protocols and mode of transmission, such as wired or wireless. Know about the types of network classified according to the areas covered such as LAN, MAN and WAN. Learn about the network topologies categorized according to the layout of equipments and computers such as star, loop, bus, or mesh topologies. There are many communication protocols used in the networking technology. It is important to know about the network architecture as networks play a very important role in today's world. 

Network architectures are sometimes classified into two broad categories:

· client-server architectures,

· peer-to-peer architectures.

In the client-server architectural model, a system is decomposed into client and server processors or processes. Servers provide computational resources (or services), which clients consume. Typically a server provides services to many clients. It is also common for clients to consume services from multiple services. Stated otherwise, there is generally a 1:M relationship between a server and its clients, and it is sometimes the case that there is a 1:M relationship between a client and the servers that it uses. The client-server architectural model supports the separation of functionality based on the service concept.

Client-server architectures are commonly organized into layers referred to as “tiers”.

Tiered Architectures

· Two-tier architectures. The system architecture consists of a data server layer and an application client layer. Data access computation is associated with the data server layer, and the user interface is associated with the client application layer. If most of the application logic is associated with the client application logic, it is sometimes referred to as a “fat client.” If it is associated with the data access server, the application client layer is sometimes referred to as a “thin client.”

· Three-tier architecture. The system architecture consists of data server layer, an application server layer and a client application layer. The application server layer facilitates the separation of application logic from presentation, and promotes distributed processing.

· Multi-tier architecture. The system architecture is a superset of a three-tier architecture, and includes additional layers for data and/or application servers.

Peer-to-Peer Architectures

In a peer-to-peer architecture model, a system is decomposed into computational nodes that have equivalent capabilities and responsibilities. This division is in contrast to a client-server architectural model, where client and server nodes are divided into server and client roles.

An example of a peer-to-peer architecture is a system of intelligent agents that collaborate to collect, filter, and correlate information.

Sometimes layered (“tiered”) and peer-to-peer architectures are combined, where the nodes in particular layers are in peer-to-peer relationships. For example, a multi-tiered architecture might include an enterprise management layer, consisting of peer nodes for such things as network management, event management, database management, Web sever management, and workload balancing.