Modes of service

The Transport Interface provides two modes of service:

• ``Connection-mode service'' is circuit-oriented and enables the transmission of data over an established connection in a reliable, sequenced manner. It also provides an identification procedure that avoids the overhead of address resolution and transmission during the data transfer phase. This service is attractive for applications that require relatively long-lived, datastream-oriented interactions.

• ``Connectionless-mode service'', is message-oriented and supports data transfer in self-contained units with no logical relationship required among multiple units. This service requires only a preexisting association between the peer users involved, which determines the characteristics of the data to be transmitted. All the information required to deliver a unit of data (for example, the destination address) is presented to the transport provider, together with the data to be transmitted, in one service access (which need not relate to any other service access). Each unit of data transmitted is entirely self-contained. Connectionless-mode service is attractive for applications that:

  • involve short-term request/response interactions

  • exhibit a high level of redundancy

  • are dynamically reconfigurable

  • do not require guaranteed, in-sequence delivery of data