Open System Services Management and Operations Guide (G06.30+, H06.08+, J06.03+)

When AF_INET sockets are used with NonStop Parallel Library TCP/IP:
• No transport-agent process or transport-provider process is involved in data routing.
• A transport-agent process must still be started in each processor to initialize the OSS sockets
interface for that processor.
• One transport-provider process must be running in the system. The transport-provider process
provides configuration compatibility for open and close operations on sockets and for
nonsensitive SCF commands.
• AF_INET sockets do not utilize AF_INET socket data buffers.
When AF_INET sockets or AF_INET6 sockets are used with NonStop TCP/IPv6:
• No transport-agent process or transport-provider process is involved in data routing.
• A transport-agent process must still be started in each processor to initialize the OSS sockets
interface for that processor.
• At least one transport-provider process must be running in the system.
• The transport-provider process provides configuration compatibility for open and close
operations on sockets and for nonsensitive SCF commands.
• Multiple transport-provider processes can be used to create separately addressed IP subnetworks
within a node. This feature is called logical network partitioning; such subnetworks are
configured and controlled through the SCF interface for the NonStop TCP/IPv6 subsystem.
• AF_INET sockets do not utilize AF_INET socket data buffers.
Transport-Agent Processes:
• The transport-agent process initializes global sockets structures and tables when it starts. A
transport-agent process that routes data (for NonStop TCP/IP or AF_UNIX sockets) among
OSS sockets application processes does so for a single processor. Each processor has its own
copy of the transport-agent process.
• HP provides a transport-agent process, $ZTAnn, where nn is the processor number. The
transport-agent process starts automatically when the processor comes up. You can bring
down its processor without first stopping the process, but you should stop all applications with
open OSS sockets before bringing down a processor. You manage the transport agent through
the SCF module of the OSS Monitor, as described in “Managing Servers” (page 90).
Transport-Provider Processes:
• A transport-provider process provides routing services for one sockets address family. Each
node has one or more transport-provider processes.
• HP provides the OSS sockets local server, $ZPLS, as a transport-provider process for OSS
AF_UNIX Release 1 sockets. For OSS AF_UNIX Release 2 sockets, HP provides an OSS
sockets local server 2 process, $ZLSnn, for each processor (instead of the $ZPLS local server
process). You manage the OSS sockets local servers through the SCF module of the OSS
Monitor, as described in “Managing Servers” (page 90).
• HP provides processes for each of its TCP/IP implementations as transport-provider processes
for OSS and Guardian AF_INET and AF_INET6 sockets. You manage an AF_INET or
AF_INET6 transport-provider process through the SCF commands for the TCP/IP subsystem
that you use for specific sockets.
AF_INET or AF_INET6 Sockets:
• Internet domain sockets allow application programs to communicate with each other or with
terminals using the underlying TCP/IP processes that also provide Telserv terminal access for
40 Introducing Open System Services