Figure 1‑2 Oracle TMA OSI TP Sample Environment
• Optional AUTOPREPARE feature that allows requests to remote services to be automatically preparedAn Oracle Tuxedo application consists of client and server programs that operate across a network of Oracle Tuxedo systems. Any client program can request services that are offered by any server program running on any computer in the application. The location of server programs is kept transparent because remote services are mapped to servers in a section of the configuration file. The TMA OSI TP architecture comprises two distinct internal components, nw-bea and nw-unisys. These two internal components extend the transparent access of the Oracle Tuxedo system by sending requests to and receiving requests from remote systems through OSI TP and supporting network software. Figure 1‑3 shows how this transparent access works.If you use multiple communication targets, you have a unique OSI TP endpoint called an association. When using unique communications targets, there is one association or connection to the remote system for each call to the remote system. After the call is complete, that association is reused by subsequent calls. There is a connection to the remote system for each simultaneous call made to the remote system. The association is released after a pre-set timer expires, turning unused resources back to the system. This pre-set timer is controlled by parameters specified in the OSI TP tailor file. Refer to “Tuning OSI TP-Specific Tables with the TAILOR File” for more information.When the multiplexed protocol is used, flow control is implemented in the following manner. When the amount of data buffered to a particular RDOM exceeds the threshold defined by StartFlowControlThreshold, GWOSITP sends a request to Tuxedo to unadvertised all services associated with the particular LDOM and RDOM involved. This allows all call and connect requests already accepted by GWOSITP to complete normally without being aborted. If one or more redundant RDOMs are configured with the same services advertised, then Tuxedo will automatically route new requests to these other RDOMs. If no other RDOM advertises the services, new tpcall or tpconnect requests will get a TPENOENT error.When the amount of data buffered to a particular RDOM falls below the threshold defined by StopFlowControlThreshold, GWOSITP sends a request to Tuxedo to advertise all services associated with the LDOM and RDOM involved.Because of the lag time between detecting flow control and unadvertising the services, it is possible for the amount of buffered data to exceed the value of StartFlowControlThreshold by a significant margin. Therefore, care should be taken when configuring StartFlowControlThreshold with a large value.
Note: For more information about the StartFlowControlThreshold and StopFlowControlThreshold parameters in the TAILOR file, refer to “Tuning OSI TP-Specific Tables with the TAILOR File.”Figure 1‑4 OSI Reference ModelThe TMA OSI TP gateway is composed of several elements that can be configured to provide OSI TP solutions. For the most part, the OSI TP domain is much like the other domain gateways. It uses the DMADM and GWADM servers provided with Oracle Tuxedo for administration.Figure 1‑5 Domain Components
• DMADM - Domain administration server
• GWADM - Gateway administration server
• GWOSITP - OSI TP Domain Gateway
Note: