Code change:
protocols and paths without requiring major changes to the application. <del> design explains the design principles behind the Transport </del> <ins> requirements explains the fundamental requirements for a Transport </ins> Services API.  These principles are intended to make sure that transport protocols can continue to be enhanced and evolve without <del> requiring too many changes by application developers. </del> <ins> requiring significant changes by application developers. </ins> concepts presents the Transport Services architecture diagram and defines the concepts that are used by both the API and

Related discussion:
text: A Transport Services system automates the selection of protocols and features and network, based on a set of Properties supplied through the TAPS interface. It is RECOMMENDED that a Transport Services system offers Properties that are common to multiple transport protocols. Specifying common Properties enables a system to appropriately select between protocols that offer equivalent features. This design permits evolution of the transport protocols and functions without affecting the programs using the system. Specifying common Properties enables a Transport Services system to appropriately select an appropriate network interface. It is RECOMMENDED that a system offers Properties that are common to a variety network layer interfaces and paths. This design permits racing of different network paths without affecting the programs using the system. Applications using the Transport Services system interface are REQUIRED to be robust to the automated selection provided by the system, including the possibility to express requirements and preferences that constrain the choices that can be made by the system. If two different Protocol Stacks can be safely swapped, or raced in parallel (see Section 4.2.2), by the Transport Services system then they are considered to be "equivalent". Equivalent Protocol Stacks need to meet the requirements for racing specified in section XX. Applications using a Transport Services system MAY explicitly require or prevent the use of specific transport features (and transport protocols) and XXXinterfaces using the "REQUIRED" and "PROHIBIT" preferences. This allows an application to constrain the set of protocols and features that will be selected for the transport service. It is RECOMMENDED that the default usage by applications does not necessarily restrict this selection, so that the system can make informed choices (e.g., based on the availability of interfaces or set of transport protocols available for the specified remote endpoint). When a Transport Services system races between two different Protocol Stacks, both SHOULD use the same security protocols and options. However, a Transport Services system MAY race different security protocols, e.g., if the application explicitly specifies that it considers them equivalent. Transport Services systems MUST NOT automatically fall back from secure protocols to insecure protocols, or to weaker versions of secure protocols. A Transport Services system MAY allow applications to specify that fallback to a specific other version of a protocol is allowed. It is RECOMMENDED that in normal use, a Transport Services system is designed so that all selection decisions result in consistent choices for the same network conditions when they have the same set of preferences.