Transports are wrappers on system-level communications resources such as TCP stacks and CPIC sockets. They provide an API which is identical to the endpoint API described in Endpoints. Typical SST users should not need to use Transports directly; only users wishing to use a previously unsupported communications resource such as UDP will need to program at this level.

To enable this isolation but retain flexibility, transports provide a configuration object (see Transport configurations) which allows the declarative setting of various transport-specific parameters such as buffer sizes or delays. These configurations are exposed to application developers and attached to transports where they are used by the SST system code. For example, you can build a declarative configuration and then instantiate it on a particular endpoint. This action creates and configures all of the required low-level transport objects while hiding the details from you.