TCP/IP Programming Manual

Table 6 RAW—Nowait Client and Server Steps (continued)
ServerClient
a. Start data transfer (t_recvfrom_nw if
connect was not called; recv_nw if connect
was called; each followed by AWAITIOX).
a. Build the header, as specified by
protocol, for type of message being sent.
b. Read and interpret message header and
interpret IP header.
b. Start data transfer (t_sendto_nw if
connect was not called; send_nw if
connect was called; each followed by
AWAITIOX).
If sending messages, perform the following, usually
in a loop:
If receiving messages, perform the
following, usually in a loop:
a. Build the header, as specified by protocol, for
type of message being sent.
a. Start data transfer (t_recvfrom_nw
if connect was not called; recv_nw if
connect was called; each followed by
AWAITIOX).
b. Start data transfer (t_sendto_nw if connect
was not called; send_nw if connect was called;
each followed by AWAITIOX).
b. Read and interpret message header
and IP header.
Close the socket (CLOSE or FILE_CLOSE_).6.Close the socket (CLOSE or
FILE_CLOSE_).
6.
Programming Considerations
When programming your applications, you should consider the following naming convention for
the processes and for the handling of buffers in data transfers.
Process Names
All NonStop TCP/IP processes, Parallel Library TCP/IP processes (TCPSAMs), and NonStop
TCP/IPv6 processes (TCP6SAMs) have a device type of 48 support calls to the FILE_GETINFO_
procedure. This provision allows applications to scan for all devices of a specified type, thereby
finding all appropriate processes in a system.
NOTE: Parallel Library TCP/IP is only available on NonStop S-series servers.
Multiple NonStop TCP/IP Processes and Logical Network Partitioning (LNP) (NonStop
TCP/IPv6, H-Series and G06.22 and Later G-Series RVUs Only)
Logical network partitioning (LNP) is a feature in NonStop TCP/IPv6 that allows you to use the
transport-service provider as a way to restrict application access to particular network interfaces.
In Parallel Library TCP/IP and in NonStop TCP/IPv6 without LNP configured, all applications in
the system have access to all the network interfaces.
When LNP is configured, the NonStop TCP/IPv6 subsystem resembles the conventional NonStop
TCP/IP subsystem with multiple TCP/IP processes. The actions necessary to support the application
in a multiple NonStop TCP/IP-process environment are similar to the actions necessary to support
the application in a multiple-LNP environment.
With LNP configured, applications that initiate connections must select the correct TCP6SAM process
as their transport-service provider. The destination IP addresses must be reachable through the
transport-service provider of that TCP6SAM. That is, the destination IP addresses must be accessible
through the LNP of the TCP6SAM.
For more information about LNP and about selecting the correct TCP6SAM process, see the TCP/IPv6
Configuration and Management Manual.
Applications doing ACCEPT_NW2 can only see listening sockets in the same LNP.
Programming Considerations 43