TCP/IPv6 Configuration and Management Manual (G06.24+)

Manage the NonStop TCP/IPv6 Subsystem

HP NonStop TCP/IPv6 Configuration and Management Manual—524523-008

6-2

Considerations for Round-Robin Filtering

This subsection describes special considerations for round-robin filtering.

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.

UDP Port Considerations

If a process maintains a context for its messages, the process should not use

round-robin filtering on shared UDP ports.

Figure 6-1. Port Collisions: Incorrect Process Pairs in Round-Robin

Configurations

VST130.vsd

Processor 0 Processor 1

LAN Adapter

Tlsrv 1

B/U

Tlsrv 3

B/U

Tlsrv 1

Processor 2

Tlsrv 3

Causes a port collision

when round-robin is used