Network Architectures

Network Architectures

A host refers to any device that is connected to a network. A host can also
be defined as any device assigned a network address.
A host can serve one or more functions:
• A host can request data, often referred to as a client.
• A host can provide data, often referred to as a server.
• A host can both request and provide data, often referred to as a peer.
Because of these varying functions, multiple network architectures have
been developed, including:

• Peer-to-Peer
• Client/Server
• Mainframe/Terminal

In a basic peer-to-peer architecture, all hosts on the network can both
request and provide data and services. For example, two Windows XP
workstations configured to share files would be considered a peer-to-peer
network.
Peer-to-peer networks are very simple to configure, yet this architecture
presents several challenges. Data is difficult to manage and back-up, as it is
spread across multiple devices. Security is equally problematic, as user
accounts and permissions much be configured individually on each host.

In a client/server architecture, hosts are assigned specific roles. Clients
request data and services stored on servers. An example of a client/server
network would be Windows XP workstations accessing files off of a
Windows 2003 server.
There are several advantages to the client/server architecture. Data and
services are now centrally located on one or more servers, consolidating the
management and security of that data. As a result, client/server networks can
scale far larger than peer-to-peer networks.
One key disadvantage of the client/server architecture is that the server can
present a single point of failure. This can be mitigated by adding
redundancy at the server layer.

In a mainframe/terminal architecture, a single device (the mainframe)
stores all data and services for the network. This provides the same
advantages as a client/server architecture – centralized management and
security of data