| Platform SDK: Windows Sockets |
The International Organization for Standardization (IOS) produces a set of standards to facilitate interconnection of computer systems. The Open Systems Interconnection (OSI) Reference Model subdivides the set into a series of layers. Winsock allows an application to use OSI Transport protocols.
Examples of OSI profiles that may be implemented are shown in the following table.
| OSI profile | Description | |
|---|---|---|
| TP4/CLNS | Transport class four over Connectionless-mode Network Service | |
| TP4/NULL | Transport class four over Null Network Service | |
| TP0/CONS | Transport class zero over Connection-mode Network Service | |
| NULL/CONS | Null Transport over Connection-mode Network Service | |
| TP0/TCP | Transport class zero over TCP/IP (RFC1006) | |
The OSI profile is designated either by the protocol parameter or the lpProtocolInfo parameter to the WSASocket API. The TP4/NULL profile is a subset of the TP4/CLNS profile and is selected by the addressing information. The default OSI profile is TP4/CLNS.
An application must use the WSAPROTOCOL_INFO structure returned by WSAEnumProtocols to discover the services provided by a particular OSI profile. For example, not all OSI profiles support connect and disconnect data.