iTP Secure WebServer System Administrator's Guide (iTPWebSvr 5.1+)

Planning the iTP Secure WebServer PATHMON
Environment
iTP Secure WebServer System Administrator’s Guide—522659-001
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Parallel Library TCP/IP: The Auto Accept Feature
For more information about the OSS environment, refer to the Open System Services
User’s Guide. For more information about the Pathway environment, refer to the
NonStop TS/MP System Management Manual.
Parallel Library TCP/IP: The Auto Accept Feature
Running with the Auto-Accept feature, an iTP WebServer no longer needs its
Distributor component. The httpd servers will assume the listening as well as the
distributing functions of the Distributor. The Distributor server class will be completely
removed from the PATHWAY environment.
When the httpd program is run (while the "start" script gets executed), it begins a series
of inquires to figure out whether to run the iTP WebServer under the new architecture or
the old one. If it passes all of its checkpoints, the iTP WebServer will be configured
according to the new architecture and runs without the Distributor. If any of the
checkpoints fail, the iTP WebServer will fall back to version WS 5.0 - the conventional
IP solution.
Running the iTP WebServer relies on the properly configured Parallel Library TCPIP
environment. Every CPU specified in the Server CPUS command (in the httpd.config
configuration file) needs to be enabled to run Parallel Library TCPIP. In other words, the
TCPMAN needs to be properly configured and run. As a result, there is a TCPMON (the
monitor process) running on every CPU specified in the Server’s CPUS command. In
the configuration phase of the startup, the iTP WebServer will validate the existence of
these processes. If not all of these processes are running, the Auto-Accept feature will
not be used. The iTP WebServer will fall back to WS 5.0 - the conventional IP solution.
Unlike the conventional TCP/IP subsystem, the Parallel Library TCPIP allows the iTP
WebServer to create a listening socket on each of these CPUs. By creating a listening
socket on each of these CPUs, the httpd servers provide the listening capability for
themselves. Therefore, mixing the Parallel Library TCPIP with conventional TCP/IP
subsystem is not permissible. If both TCPSAM process and conventional TCP/IP
process are specified as the transport service providers, the Auto-Accept feature will not
be enabled. The iTP WebServer will be running exactly as WS 5.0.
Migration Considerations For Parallel Library TCP/IP Support
Parallel Library TCP/IP requires the httpd server to be static server in a PATHWAY
environment in order to perform well. Although it does provide the ability to create
dynamic httpd servers while the request load exceeds the static capacity, it requires more
system resources serving requests. The response time for some of the requests may not
be adequate when the new servers are being created. As the matter of fact, this is true
even in prior versions (WS 5.0 and before).
Besides, it also posts a risk of losing a few connections when the PATHWAY removes
the dynamic servers. The Auto-Accept feature traded the Distributor with better
performance. The better performance is achieved by having the httpd servers accept the
new connection requests directly from transport layer (Parallel Library TCP/IP) rather
than having the Distributor accept the new connection and then distribute to httpd
servers.