CORBA 2.3.3 Getting Started Guide (NonStop CORBA 2.3.7+)

number of Comm Servers.
To provide additional external port connections, the administrator can add multiple instances of
HP NonStop TCP/IP to the NonStop CORBA system. Each instance of NonStop TCP/IP increases
the number of available TCP/IP ports and, therefore, the number of clients the ORB can support.
Multiple instances of NonStop TCP/IP allow Comm Servers to listen on the same IP address or
different IP addresses (port numbers must be unique within the scope of the TCP/IP process).
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The administrator can configure NonStop CORBA to use the Parallel Library TCP/IP product.
This product allows a single TCP/IP port to be shared by multiple processes, with each connection
being established in round-robin fashion. Using Parallel Library TCP/IP increases capacity (there
are more processes available to share the load) and improves fault tolerance (a software or
processor failure does not render the address unusable).
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Network session concentration to reduce the number of IP ports needed in the host●
Within the HP system, the NonStop CORBA system uses TS/MP for communication between
application processes, Comm Servers, and application servers. This design improves throughput
while minimizing the IPC resources needed by the ORB.
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You can increase the number of remote clients connected to the NonStop CORBA ORB without
requiring configuration changes on either the client workstation or the NonStop CORBA system. When a
remote client first makes a connection to the ORB, the NonStop CORBA system transparently assigns an
existing port number to the client.
In practice, a single Comm Server can handle hundreds of clients, and a TCP/IP process can handle
hundreds of Comm Servers.
Scalability of Application Server Processes
NonStop CORBA allows the scalability of application server processes by supporting the use of TS/MP
server pools. A server pool consists of multiple processes (CPU resources) that implement the same
application logic. TS/MP provides load balancing, dividing requests among the servers in the pool.
A client program need not be aware of whether an object class is running in a server pool or an individual
server process. In fact, the same server program normally can run in either mode; you specify the
preferred mode in a configuration file for each server. (HP recommends the use of server pools to
provide availability, autorestart, scalability, and load balancing.)
Compatibility of NonStop CORBA Components
NonStop CORBA provides source code portability for applications that comply with the CORBA 2.3 and
the OMG portability specifications. Most of the HP differentiated features, such as scalability, are
transparently available; application servers ported to the HP system do not need to change in order to
exploit the scalability of NonStop CORBA.