Architecture and topology of networks

In the context of networks, topology refers to the structure of inter-connected participants to ensure a mutual data flow.

The topology of a network is one of the factors determining its reliability: only when redundant paths exist between the nodes is the functionality maintained when individual connections or devices (e.g. a switch) fail. In this case, there are several alternative ways on top of the standard working way.

A distinction is made between physical and logical topology.

• Physical topology refers to the cabling layout.
• Logical topology illustrates how data flows between devices in a network.

Knowing the basic structure of networks will also be useful when assessing their performance and reliability or when sizing up potential investment costs and selecting suitable hardware.

Topologies

The most frequently applied topologies in practice are simplified in the diagram below:

Big industrial sites and their production lines often use a structure comprised of multiple different topologies.

Client-Server-Architecture

The client sends a request to the server to use a certain service, which in turn receives and evaluates the request, supplying the client with the requested service. This way of communication takes place by means of transactions. A transaction must meet certain criteria. For example, it can’t influence other transactions and consistent data must remain after the transaction.

octoplant example

A user wants to process project data of a certain plant.

The UserClient requests the project data through a Check-Out from the octoplant server. The user can use and modify this project data with their locally installed application. For these changes to be versioned effectively, you must request a Check-In on the server (a saved copy of the new product version).

Check-Out and Check-In are therefore transactions.

This is admittedly a simplified version of the processes involved in client-server communication.