wRTOS provides processing and networking capability through a TCP/IP Stack within the RTSS environment. To maximize portability between wRTOS and Windows, wRTOS provides an API that conforms to a subset of the functions defined in the Windows Sockets 2.0 (Winsock) specification for Windows. For more information, see Using the Winsock API.
The TCP/IP Stack relies on the NL2 for Layer 2 access. To view a list of network cards supported off-the-shelf by the NL2, see Supported Network Interface Cards.
The diagram below shows a sample OSI architecture model and how it maps to the TCP/IP architecture. The lower levels of the TCP/IP Stack consist of independent protocols that support specific hardware interfaces, transport mechanisms, and other components, while the higher layer protocols are interfaces into the user wRTOS-enabled application code.
The TCP/IP Stack layers perform these functions:
| Layer | Description |
|---|---|
|
Physical Layer (1) |
This layer is implemented by the PHY chip. It is responsible for transmitting raw bits on the wire. |
|
Data-Link Layer (2) |
Specifies the control characters and the lowest level mechanisms for transmitting packets of data in successive small segments (called frames) between nodes. In wRTOS, this is handled by the Network Link Layer (NL2). |
|
Network Layer (3) |
Means by which packets of data are routed through the network from sender to receiver. This level is concerned with the path the packets take, not the content of those packets. |
|
Transport Layer (4) |
Generally responsible for delivering of a potentially large message from the sending application on one network to the receiving destination. |
|
Session Layer (5) |
Provides the mechanism for opening, closing and managing a session between end-user application processes. The TCP/IP Stack does not implement Session layer protocols. |
|
Presentation Layer (6) |
Responsible for the formatting and delivery of information to the application layer for further processing or display. The TCP/IP Stack does not implement Presentation layer protocols. |
|
Application Layer (7) |
wRTOS TCP/IP enabled RTSS application. |
