TCP/IP (Parallel Library) Configuration and Management Manual

Introduction
HP NonStop TCP/IP (Parallel Library) Configuration and Management Manual—522271-006
2-5
Round-Robin Filtering
Configuring the System to use Round-Robin Filtering
You must set the following DEFINE to enable round-robin filtering on your server
processes:
ADD DEFINE =PTCPIP^FILTER^KEY, class map, file file-name
file-name is arbitrary but serves as the key or password. This key provides a
measure of security: only users who know the key can access round-robin on the port.
It can be up to eight alphanumeric characters; the first character must be a letter. The
default setting is non-round-robin. If you don’t specify the file-name, round-robin
filtering does not take effect. In this case, whoever registers the first application has
exclusive use of the port. Each application that uses round-robin filtering on the same
port must use the above ADD DEFINE with the same key.
If you specify only the PTCPIP^FILTER^KEY, all applications that share that DEFINE
also share all ports. To limit the shared ports, add one or both of the following
DEFINEs:
ADD DEFINE =PTCPIP^FILTER^TCP^PORTS, FILE Pstartport.Pendport
ADD DEFINE =PTCPIP^FILTER^UDP^PORTS, FILE Pstartport.Pendport
The startport and endport variables are integers specifying the allowable port
range. The =PTCPIP^FILTER^TCP^PORTS key limits the shared TCP ports to the
range defined in startport and endport. The =PTCPIP^FILTER^UDP^PORTS key
limits the shared UDP ports to the range defined in startport and endport. Ports
outside those ranges are not shared.
You must always specify the =PTCPIP^FILTER^KEY DEFINE to enable round-robin
filtering. If you want to limit shared TCP and UDP ports, add the appropriate DEFINE
after the =PTCPIP^FILTER^KEY DEFINE.
Port Collision Considerations for Listening Processes
When you configure a set of listening processes for round robin, do not allow their
primary and backup processors to overlap. That is, if you configure primary and
backup listening processes, do so in distinct pairs. For example, if you have four
processors, 0 through 3, and you want to configure primary and backup TELSERV
processes for round-robin distribution, configure a primary and backup TELSERV pair
in processors 0 and 1 and another primary and backup TELSERV pair in processors 2
and 3.
Only one listening process per processor per port is allowed. If the processor running
the primary listening process fails, the backup process in the other processor takes
over listening on that port but if another listening process in the backup processor is
already listening on the same port, the backup process receives an error and cannot
listen on that port.