Session layer (SL) PDUs

The PDU trace file provides information used to analyze session layer (SL) PDUs that are exchanged between the SFD and the SAG. You can use it to determine, among other things, whether an SL PDU containing a particular FIN ISN/OSN in its FIN batch was passed to or from the SAG. The PDU trace file is written when the FIN batch buffer is flushed, for example, when the SL PDU is passed to the SAG.

To control the SL PDU trace function, set the attributes of COs of type DnfTrace by issuing commands of the form:

add -ct DnfTrace  -ou SYSOU -co COname -attr Level   -val traceLevel
add -ct DnfTrace  -ou SYSOU -co COname -attr Size    -val <TraceFileSize>

where:

COname

The name of a CO that determines to which LTs the specified PDU trace level or trace file size apply:

DnfSnfPDU: The trace level or trace file size specified for this CO applies to all LTs, except for those for which a destination CO or LT name CO was specified.
DnfSnfPDULdestination: The trace level or trace file size specified for this CO applies to all LTs that belong to the specified destination, except for those LTs for which an LT name CO was specified.
DnfSnfPDULltname: The trace level and trace file size specified for this CO apply to the specified LT (BIC9) only.

traceLevel

A number that determines what is written to the trace file:

0: Nothing.
1: SNF SL PDU Data Reference.
2: If available, each APDU message; otherwise, the SNF SL PDU request payload, unformatted.
3: If available, each SNF SL PDU request payload; otherwise, the complete SNF SL PDU, unformatted.
4: The complete SNF SL PDU, unformatted.
5: The complete SNF SL PDU, formatted to that it is easier to see the hierarchical structure of the message.

<TraceFileSize>

A number that determines the number of trace files created for each LT session, and the maximum size of each:

The number 0 specifies that one trace file is to be used, and no limit is to be placed on the size of the trace file
A number from 1 to 100 specifies that three trace files are to be used, and the maximum size of each trace file is to be that number of MB

To activate these changes:

Commit, approve, and deploy the changes for SYSOU:
```
com -ou SYSOU
app -ou SYSOU
dep -ou SYSOU
```
Logout and relogin all LTs that are affected by the changes.

Using the three types of CO names, you can set the trace levels and trace file sizes for:

A single LT (BIC9)
All LTs of a particular destination that are not already specified by means of a BIC9
All LTs that are not already specified by means of a BIC9 or BIC8

For example, assume that you issued the following add commands:

add -ct DnfTrace -ou SYSOU -co DnfSnfPDU           -attr Level  -val 3
add -ct DnfTrace -ou SYSOU -co DnfSnfPDU           -attr Size   -val 10
add -ct DnfTrace -ou SYSOU -co DnfSnfPDULXXXXUSNY  -attr Level  -val 2
add -ct DnfTrace -ou SYSOU -co DnfSnfPDULXXXXUSNYA -attr Size   -val 5

The following would apply:

For an LT with the name XXXXUSNYA:
- The level would be 2 (this is the level set for CO DnfSnfPDULXXXXUSNY)
- The size would be 5 (this is the size set for CO DnfSnfPDULXXXXUSNYA)
For an LT with the name XXXXUSNYB:
- The level would be 2 (this is the level set for CO DnfSnfPDULXXXXUSNY)
- The size would be 10 (this is the size set for CO DnfSnfPDU)
For an LT with the name XXXXUSSFO:
- The level would be 3 (this is the level set for CO DnfSnfPDU)
- The size would be 10 (this is the size set for CO DnfSnfPDU)

PDU trace files are written to a directory with a name of the form

FSMInstanceDir/ltname/trc

For example:

/var/ftmswift_v300/run/fsm/XXXXUSNYA/trc

If no limit was placed on the size of the trace file, one trace file is created with a name of the form

SFD.timestamp.pdu

where timestamp represents a timestamp showing the month, day, hour, minute, and second on which the file was created, for example:

SFD.0921173014.pdu

If a maximum trace file size was specified, then three trace files are created for each LT session, each with a different suffix:

pdu.a
pdu.b
pdu.c

For example:

SFD.0921174234.pdu.a
SFD.0921174234.pdu.b
SFD.0921174234.pdu.c

The SFD begins writing its PDU trace data to the file with the suffix pdu.a. When this file reaches the specified limit, the SFD switches to the file with the suffix .pdu.b. When that file reaches the specified limit, the SFD switches to the file with the suffix pdu.c. When that file reaches the specified limit, the SFD switches back to the file with the suffix pdu.b., and overwrites the previously recorded trace data. The SFD continues switching between the pdu.b and pdu.c files as each becomes full. The data recorded in the file with suffix .pdu.a is not overwritten.