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Virtual Machine/System Product: System Programmer’s Guide, Release 4
3.2.1 Types of Traces
Six types of IBM traces can be useful for isolating problems in the DECnet
SNA network:
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VTAM buffer contents trace
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VTAM I/O trace
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Generalized PIU trace
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VTAM line trace
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SDAID trace
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VTAM internal trace
Choose the type of trace according to the type of problem you have.
3.2.1.1 VTAM Buffer Contents Trace
A VTAM buffer contents trace (TYPE=BUF) shows the contents of inbound
and outbound message buffers. A buffer contents trace helps you determine
whether a problem is in the host (VTAM or an application program) or in the
network. It traces all the messages that are sent to or received from a VTAM
application. Request a buffer contents trace to trace path information units
(PIUs) being sent to and received from a VTAM application program.
3.2.1.2 VTAM I/O Trace
The VTAM I/O trace (TYPE=RNIO) records the order in which PIUs flow
between network nodes and VTAM. You might use this trace to determine
whether the Gateway-ST software receives all the responses that it should and
whether VTAM forwards all the requests issued by the Gateway-ST.
The content of the I/O trace is similar to that of the buffer trace except that
the I/O trace records less user data. Use the PRDMP (print dump) service aid
to edit and print the I/O trace records.
3.2.1.3 Generalized PIU Trace
The generalized PIU trace (TYPE=GPT) collects PIU trace data obtained
by IBM’s NCP. LUs associated with the PU are automatically traced when
traffic flows over them. Request a generalized trace of all NCP buffers in the
following situations:
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To determine whether NCP has received or sent PIU data.
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