2.1.5 Member Protocol Functional Relationships
The following diagram represents the dependencies of the protocols that are used by the transaction processing services.

Figure 5: Transaction processing services protocol dependencies
This section describes the roles played by each member protocol in the overall function of the system:
MSDTC Connection Manager: OleTx Transaction Protocol (DTCO), as specified in [MS-DTCO], supports all the communications between the components as described in section 2.1.2, except those between the management tool and the transaction manager, between the application and the application service, between the application and the resource manager, and between the application service and the resource manager. The abstract state machine that drives the transaction lifecycle, as specified in [MS-DTCO] section 1.3.1, is defined only in [MS-DTCO]. An implementation of this state machine is necessary for any implementation of a transaction manager, and therefore, any implementation of the protocols, as specified in [MS-DTCM], [MS-TIPP], [MS-DTCLU], [MS-CMOM], [WSAT10], [WSAT11], [MS-WSRVCAT], and [MC-DTCXA], requires a DTCO implementation.
MSDTC Connection Manager: OleTx Transaction Protocol Logical Unit Mainframe Extension (DTCLU), as specified in [MS-DTCLU], supports communication from the external resource manager to the transaction manager. The system uses this protocol to provide transactional support to implementations of LU 6.2, as specified in [IBM-LU62Guide].
MSDTC Connection Manager: OleTx Transaction Internet Protocol, as specified in [MS-DTCM], supports communication from the external application to the transaction manager and external application service to transaction manager communications. The system uses this protocol to allow external application and external application services to request the system to pull a transaction from, or push a transaction to, an external transaction manager that implements Transaction Internal Protocol (TIP).
Transaction Internet Protocol (TIP) Extensions, as specified in [MS-TIPP], supports external application to transaction manager communications, external application service to transaction manager communications, and external transaction manager to transaction manager communications. This protocol represents an extension to TIP as specified in [RFC2371]. It provides mechanisms to associate TIP transactions and the transactions that are internal to the system. It also provides mechanisms for driving a single atomic outcome, coordinating the distribution of this outcome, and transaction propagation.
WS-AtomicTransaction protocol ([WSAT10] and [WSAT11]) is an alternative transaction coordination protocol. It supports external application to transaction manager communications, external application service to transaction manager communications, and external transaction manager to transaction manager communications.
WS-AtomicTransaction (WS-AT) Version 1.0 Protocol Extensions, as specified in [MS-WSRVCAT], supports external application to external transaction manager communications, and external application to external application service communications. The system uses this protocol to provide support for external applications to exchange system-specific transaction propagation information with external application services. By using the data structures in the WS-AtomicTransaction (WS-AT) Version 1.0 Protocol Extensions and also by using DTCO, external applications can query system-specific transaction propagation information from the system. External applications can then include this information in WS-AtomicTransaction messages when communicating with external application services. If the external application service also supports the protocols as specified in [MS-WSRVCAT] and [MS-DTCO], then for performance reasons, it can choose to communicate with the system by using core protocols rather than by using the WS-AtomicTransaction Version 1.0 Protocol Extensions. See [MS-WSRVCAT] for further details about this protocol and its usage scenarios.
MSDTC Connection Manager: OleTx XA Protocol, as specified in [MC-DTCXA], supports communication from:
An external transaction manager to a transaction manager.
An external application to a transaction manager.
An external resource manager to a transaction manager.
The system uses this protocol to provide transactional support for external transaction managers and external resource managers by implementing the protocol, as specified in [XOPEN-DTP]:
MSDTC Connection Manager: OleTx Management Protocol, as specified in [MS-CMOM], is used for communications between the management tool and the transaction manager and performs administration and configuration operations on the system.
MSDTC Connection Manager: OleTx Transports Protocol, as specified in [MS-CMPO], is a framing and message transport protocol. It implements remote procedure call (RPC) interfaces, as specified in [MS-RPCE], for establishing duplex sessions between two partners and for exchanging messages between them. [MS-CMPO] describes specific restrictions on the use of RPC interfaces. Details are specified in [MS-CMPO] sections 1.3, 1.7, and 2.
MSDTC Connection Manager: OleTx Multiplexing Protocol, as specified in [MS-CMP], supports both multiplexing multiple logical sessions over a single CMPO session, and multiplexing multiple protocol messages into a single CMPO.