gtpc1m1d | Transmission Control Protocol/Internet Protocol |
Figure 15 provides an overview of the TCP/IP native stack support
components.
Figure 15. TCP/IP Native Stack Support Components
- Socket application
- The user application or TPF middleware that issues socket application
programming interface (API) functions.
- Socket API processing
- Processes socket API functions. For calls that require packets to
be sent out, the IP send component is called. For calls to read data,
and the necessary data has already been received from the network, the call is
processed completely by this layer.
- IP send
- Builds all packets and adds them to the IP output queue to send them to
the network, or sends the packets directly to the OSA-Express card. If
a large amount of CDLC output packets exist, a write channel program will be
issued if an available IP router is found to write out the packets immediately
(rather than wait for polling to write out the packets).
- IP scan
- Activated several times per second to poll the network (send and receive
packets) and retransmit lost TCP output messages.
- IP trace read processing
- Activated when packets are received from the IP network. Initial
processing of a packet is done to identify the socket that the packet is
destined for, process TCP connection requests, and stand-alone acknowledgments
of TCP data. Packets containing user data are passed via the TPF input
list to IP Opzero for further processing.
- IP Opzero
- Reassembles fragmented packets and then passes the entire message to the
appropriate protocol layer.
- TCP Opzero
- Processes data received for stream sockets. This includes
processing out-of-order data and acknowledging the receipt of data.
- UDP Opzero
- Processes data received for datagram sockets.
- RAW Opzero
- Processes data received for RAW sockets. This includes processing
ICMP requests (like PING requests), ICMP error messages, and user-created RAW
sockets.