Chapter 5 Designing the integration Layer Integration Styles, Protocols, Systems, and Patterns A DXP supports multiple design patterns and integration platforms as mentioned previously. Integration patterns supported and their implementation models are described in the consecutive segments of this chapter. Integration Styles There are different types of styles to consume data, for example, RPCs (remote procedure calls) and messaging file transfer, database, RMI (remote method invocation), that help to integrate multiple applications so that they can exchange data or information with each other. Remote procedure calls • gRPC (remote procedure calls): gRPC is a modern open-source high- performance RPC framework that can run in any environment. It can efficiently connect services in and across data centers, with pluggable support for load balancing, tracing, health checking, and authentication. It is also capable of browsers to back-end services connecting devices and mobile applications. Hyperledger fabric blockchain project uses gRPC to communicate to the blockchain network. Messaging File Transfer • JMS: It is used to send messages between applications; it is asynchronous in nature, which means the client is not required to send a request, and the message will arrive automatically to the client. It is of two types. One is the point-to-point messaging domain, where one message is delivered to one receiver only and a queue is used to achieve that. The other is the publisher-subscriber messaging domain, which is like broadcasting in that one message is delivered to all the subscribers; to achieve that, a destination called a topic is used to hold and deliver messages. • MQTT (Message Queuing Telemetry Transport): MQTT is a publisher-subscriber based messaging protocol that works on top of the (Transmission Control Protocol/Internet Protocol) TCP/IP protocol. It is designed for constrained devices with low bandwidth. It is best suited for IoT-based applications, as it allows you to send commands to controls, and to read and publish from IoT sensors. 157