CM Server architecture

The CM API clients, Rational® ClearQuest® Web and CCRC, communicate with the CM Server by an implementation of the CM API.

The CCRC HTTP and CM Server Web services servlets contained within WebSphere® Application Server are the front end of the CM Server. ClearCase® RPC (CCRPC) and ClearQuest RPC (CQRPC) servers connect CM Server to the ClearCase and ClearQuest repositories.

The CM Server is implemented as one or more J2EE applications hosted in the WebSphere Application Server. Each WebSphere Application Server instance includes TeamEAR. The clients of the TeamEAR servlets (such as CQWebEAR for ClearQuest Web) might or might not be in the same WebSphere Application Server instance, depending on how you want to structure your environment. For example, you can deploy ClearQuest Web on a WebSphere Application Server instance on one machine that connects to TeamEAR on a WebSphere Application Server instance on a different machine.

The CM Server architecture is composed of three tiers:
  • The Web tier: The entry points to CM Server are J2EE servlets that run in the Web containers of one or more servers on which WebSphere Application Server is running. Servers that run IBM® HTTP Server can serve as front ends and as load-balancing servers to the servers that run WebSphere Application Server.
  • The application tier: The front-end servlets invoke the services of the application tier, which are Enterprise Java™ Beans (EJBs) that run in the EJB containers of one or more WebSphere Application Servers.
  • The data tier: Access to Rational ClearCase and Rational ClearQuest repositories is by remote procedure call (RPC) interfaces to back-end server processes that are integrated into the WebSphere framework as Java 2 Connector resources.

The following figure shows the major components of the WAN client and server architecture. The CM Server architecture image shows boxes that represent the clients pointing to the box that represents WebSphere Application Server and the components running in WebSphere Application Server. The bottom of the image shows the data repositories for Rational ClearCase and ClearQuest that are pointed to from the WebSphere Application Server box.


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