STMS transaction is executed initially in client 000 with ddic authorization in order to configure TMS. The following changes occur in the system when you execute STMS for TMS configuration:
All repository objects are grouped into logical unts called packeges(formerly known as “Dev Classes”).
The definition of each package contains an assignment to a transport layer.
Transport routes are used to define in which target system you want to consolidate change requests and which SAP systems are forwarded this information automatically.
All the development projects developed in a same SAP system and transported using the same transport route are grouped together to form transport layer.
There are two types of transport routes:
-Consolidation route (usually defined between Dev and QA systems)
-Delivery route (usually defined between QA/Test and Production systems)
STMS is a transaction used for transport management functionality in SAP landscape.
There are few steps involved to configure TMS before you can use it after system setup:
-Configure transport domain
-Configure transport route
-Choose transport strategy
-Configure QA approval procedure
-Configure transport workflow
There are four types of transport requests:
1. customizing request (Contains client specific changes recorded in a single client)
2. Workbench request (Contains changes made to the repository objects of ABAP work bench)
3. transport of copies (Allows to transport any sub objects into object list to any other SAP system)
4. relocation (Use this when development system of a complete package is to be changed on permanent basis)
Transport domain is the collection of transport controller, trans directory and all other systems in the group.
Transport domain controller is a system which has trans directory, and in which the total landscape is designed and maintained
SAP Basis Knowledgebase 