Using the TMS Capability Across Domains


	BEA Home \| Events \| Solutions \| Partners \| Products \| Services \| Download \| Developer Center \| WebSUPPORT
	http://www.oracle.com/technology/documentation/index.html \| Site Map \| Search \| PDF Files \| Contact \| Glossary

Tuxedo Documentation \| Using the BEA Tuxedo Domains Component \| Local Topics \| Previous Topic \| Next Topic \| Contents

In the BEA Tuxedo system, the TMS is a special server that is implicitly associated with server groups that use X/Open XA-compliant resource managers. The TMS server releases application servers from the delays associated with the distributed 2-phase commitment protocol. TMSs coordinate the commitment of a transaction via special service requests to the TMS service, which is offered by all TMS servers.

In a Domains environment, GWTDOMAIN gateways are not associated with an XA-compliant resource manager. The Transaction Processing Working Group (TPWG) of X/Open has proposed an advanced XA interface. This interface is not used in the BEA Tuxedo system because the interface does not match the highly asynchronous and non-blocking model required by the gateway. While Domains gateways do not use a separate TMS server, they do offer the Transaction Manager Servers (TMS) capability, which allows gateways to coordinate the 2-phase commitment of transactions executed across domains.

How Gateways Coordinate Transactions Across Domains

Domain gateways advertise the TMS service and perform all operations associated with that service. Messages sent to this service are placed on the queue used by the appropriate gateway group, and the gateways manage the transactions associated with the group.
A gateway can act as a subordinate of transactions coordinated by another group within the domain. In this case, the gateway is a superior of the transaction branches executed in other remote domains. When acting as a subordinate of a transaction coordinated by a remote domain, the gateway also acts as the coordinator for all groups in the local domain accessed by the transaction. The gateway, acting as both subordinate and coordinator, is illustrated in the following figure.
The Gateway as Subordinate/Coordinator of Another Domain Group
As a coordinator of transactions within the domain, the gateway manages the commitment of a transaction for a particular client. This is illustrated in the following figure.
Client Commit Managed by a Gateway
Gateways manage transaction commitment for a particular client or for a server that uses the forwarding service with the AUTOTRAN capability. When this combination is used, the last server in the forward chain (the Domains gateway) issues the commit and becomes the coordinator of the transaction. (A domain gateway always acts as the last server in a forward chain.)
Gateways automatically start and terminate transactions for remote services specified with the AUTOTRAN capability. This capability is required when an the application administrator wants to enforce reliable network communication with remote services. Administrators can specify this capability by setting the AUTOTRAN parameter to Y in the corresponding remote service definition.
For more information, refer to the DM_REMOTE_SERVICES Section of DMCONFIG(5) in the File Formats, Data Descriptions, MIBs, and System Processes Reference.
Gateways map the BEA Tuxedo system transaction protocol to the networking transaction protocol used for interoperation with remote domains. How this mapping is done depends on which instantiation of Domains you are using: TDomains, SNA, or OSI TP.