Splitting the system's functionality over multiple services has several benefits. First of all, each service can be maintained and deployed separately. This helps the team focus on a given task, without the need to understand every possible interaction within the system. It also enables agile development as tests only have to cover a particular service, not the entire system.
The second benefit is that the modularity of the services helps create a distributed system. With a network (usually based on the Internet Protocol) as a means of communication, services can be split between different machines to provide scalability, redundancy, and better resource usage.
Implementing new features and maintaining the existing software is a difficult task when there are many producers and many consumers for each service. This is why SOA encourages the use of documented and versioned APIs.
Another way to make it easier for both service producers and consumers...
