Compaq Reliable Transaction Router manual Architectural Concepts, Three-Layer Model

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Architectural Concepts

This chapter introduces concepts on basic transaction processing and RTR architecture.

The Three-Layer Model

RTR is based on a three-layer architecture consisting of frontend (FE) roles, backend (BE) roles and router (TR) roles. The roles are shown in Figure 2–1. In this and subsequent diagrams, rectangles represent physical nodes, ovals represent application software, and DB represents the disks storing the database (and usually the database software that runs on the server).

Client processes run on nodes defined to have the frontend role. This layer allows computing power to be provided locally at the end-user site for transaction acquisition and presentation.

Server processes (represented by ``Server'' in Figure 2–1) run on nodes defined to have the backend role. This layer:

•Allows the database to be distributed geographically.

•Permits replication of servers to cope with either network, node or site failures.

•Allows computer resources to be added to meet performance requirements.

Architectural Concepts 2–1