A distributed system is a system that has several nodes that perform parallel, data processing. Nodes do not necessarily have to have homogeneous roles in the task performed, heterogeneity being very common.

Can be considered among the types of Distributed Systems:

• Cloud Computing Systems.
• IoT - Internet of things.
• P2P systems.
• Botnets.
• systems that collaborate with each other in integrated through message exchange.
• Cryptocurrencies.
• etc.

The rule here is that there are multiple parts of the system chatting in an integrated way. Several protocols can be used to govern the communication of these. The most common at present are SOAP (along with related technologies such as WS -*, WSDL, UDDI, among others) and REST (which takes advantage of HTTP). There are and have been other technologies in this regard, such as the CORBA (which, fortunately, is falling disused). Integration can be done even via email, FTP, TCP or UDP sockets.

The structure of the system as a whole is often an orchestration, where one of the nodes initiates and coordinates the operation as a whole and the other nodes only perform specific tasks (and may themselves be orchestrations). Another structure is that of choreography, where the services talk to each other but without a central control or coordination.

In some cases, a even node (or node pool) can be part of multiple distributed systems. For example, Company a's system can talk to the post office system to map CEPs to streets. Meanwhile, Company B, which has no relationship with company a, can do the same.