NS3000/iX Operations and Maintenance Reference Manual (36922-90039)

Chapter 5 75

Common Network Problems

Common Problems and Actions

If a retransmission error is returned in a log message or in an

IPCCHECK error code for NetIPC applications, ﬁrst check that the

remote node is up and that its transport has been started. If so, check if

the retransmission timeout error is an isolated event or an ongoing

problem. Examine a formatted log ﬁle for the period up to and including

the error.

If the problem is ongoing, then take the appropriate action:

• If the log messages show initial TCP connection failures due to a

heavily loaded remote node, conﬁgure a longer Initial

Retransmission Interval for the Transmission Control Protocol

(TCP) Conﬁguration Screen. This is in the NETXPORT branch of the

NMMGR network conﬁguration. Also, you can increase the

connection assurance interval on this screen if there are a large

number of TCP connections conﬁgured.

• If there are IPCLOOKUP failures, and the log messages show PXP

timeouts due to a heavily loaded remote node, conﬁgure a longer

default retransmission interval for the PXP data screen. This is also

in the NETXPORT branch.

• If the problem affects established connections and none of the above

conditions apply, then conﬁgure a longer retransmission interval

upper bound, or conﬁgure a higher number of maximum

retransmissions per packet for the Transmission Control Protocol

(TCP) Conﬁguration Screen.

NetIPC Errors

NetIPC programmatically creates processes on both local and remote

systems. These processes must be released, along with any descriptors

and resources, after the program completes. Unless these process are

terminated properly, errors may result.

NetIPC Shutdown Errors

The NetIPC call IPCSHUTDOWN releases a descriptor and any resources

that are associated with it. Since system resources are used as long as

call sockets and destination sockets exist, it is important that

application programs release the sockets whenever they are no longer

needed.

Before a process terminates, it should terminate its connection with

IPCSHUTDOWN. Because this termination takes effect very quickly, all of

the data that is in transit on the connection is lost when the connection