TCP/IP (Parallel Library) Configuration and Management Manual

Configuring Parallel Library TCP/IP for Complex and
Heavy-Use Environments
HP NonStop TCP/IP (Parallel Library) Configuration and Management Manual—522271-006
3-2
Four Listening Methods
Four Listening Methods
Networking methods fall into four types:
•
Standard Listening Model
•
Monolithic Listening Model
•
Distributor Listening Model
•
Hybrid Listener Model
Standard Listening Model
In this method, you have a single process which listens for incoming connections.
When an incoming connection occurs, the listening process spawns a new server
process (which can run in another processor) then passes that server process the
caller's IP address and port number. That spawned process assumes ownership of the
port and does its own socket I/O.
This method allows for parallel instances of the server process. For example, the
common LISTNER spawns instances of FTPSERV. The LISTNER process is the
common point where all incoming connections are handled, but control and data flow is
handed off to separate instances of server processes which can be distributed across
processors.
Because it passes connections off to other processors and can use all processors in
the system, the standard listener model provides scalability.
The standard listener model can benefit from the Parallel Library TCP/IP architecture
because Parallel Library TCP/IP eliminates the hop that has to occur between the
spawned server process and the processor where the TCP/IP process resides. That
hop occurs on the server process’ first socket call and every subsequent send/receive
call. In Parallel Library TCP/IP, those calls are handled locally, within the server’s
processor.
Figure 3-1
on page 3-3 shows a standard listener distributing a connection to a
different processor. Step 3 of the conventional TCP/IP environment (of Figure 3-1
on
page 3-3) shows that FTPSRV must hop to Processor 0 where the TCP/IP process
resides to access the adapter. By contrast, in the Parallel Library TCP/IP environment,
in Step 3, FTPSRV has direct access to the adapter.