CORBA 2.3.3 Administration Guide (NonStop CORBA 2.3.3+)

multiple Comm servers can be configured. Using multiple Comm Servers allows larger volumes of traffic to be handled
because the load is spread across multiple processors.
Parallel Library TCP/IP
Another way to increase capacity and fault tolerance is to configure the IIOP connectivity components of your system
(Comm Server, LSD, ILSD, and BSD processes) to use Parallel Library TCP/IP. With this configuration, multiple Comm
Server processes running in a pool can share the same port. A round-robin filter distributes the incoming connections among
the Comm Server pool. When configured this way the Comm Server pool appears as a single IP host to the outside world.
Figure 17 shows the original way of configuring TCP/IP in a Himalaya system. Note:
There is one Comm Server per port, limiting throughput on that port.●
There is a TCP/IP process between the ServerNet adapter and a Comm Server, requiring a message system hop.●
Figure 1.7. Original TCP/IP
Each Fast Ethernet ServerNet Adapter (FESA) corresponds to a TCP/IP port.
By comparison, configuring the IIOP connectivity components of your system to use Parallel Library TCP/IP allows
publishing a single port for up to 16 Comm Server processes. Message system hops are reduced by moving execution of TCP
data-path functions from the TCP/IP process into the user process (Comm Server in this case), referencing the Parallel
Library TCP/IP SRL.
Figure 1.8. Parallel Library TCP/IP