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Walkthrough Wednesdays

How to take MDL Call Trace in Cisco PGW2200 to identify the call failure


MDL Traces

The MDL tracer gives a C++ object instantiated by the engine that contains a collection of TraceFile objects for the call.

This MDL trace can give some details where the problem is related on the PGW 2200 and helps during the troubleshooting of

call failures. This document helps you to collect the MDL Trace in PGW2200, also the display options available in the trace helps

you to trace the call failures.

Collect the PGW 2200 MDL Trace

Use this procedure in order to collect an MDL trace via the MML command STA−SC−TRC (Start Trace).

1.Identify the Originating SS7 SigPath Number or the Originating TrunkGroup Number on which calls

are placed.

2. Rotate the log: run script under /opt/CiscoMGC/bin/

3.Start the MDL trace:

mml>sta−sc−trc:<ss7sigPath name | orig trunkgroup number>:CONFIRM

4. Perform a test (make a call).

5.Stop the MDL trace:


6. Identify the Call Id (C:) of the bad call.

If this test call is made in a test environment, only one CALL_ID displays.

Note: These files can contain tracings from many calls that are all mixed up together if the capture is

taken on a production PGW. Each tracing record in the file has a specific record type and records

information of a type that relates to that record. Each record has a Call ID that relates it to a specific


7. Convert the MDL trace into a readable format:

a. Go to the /opt/CiscoMGC/var/trace directory.

b. Run this command: <trace file name>

For example:


mgcusr@mgc−bru− _ss7path_20040116103221.btr ca/sim/sp Trace File Utility Mistral Version 1.2


Retrieving _ss7path_20040116103221.btr trace file Call ID's, please wait...

Enter one of the following commands:

S = Simprint in less

F = Simprint with printing of sent and received Fields in less

D = Display trc trace in less

G = Display trc trace in less (Generated)

C = Convert to trc trace file

A = Display CA file in less

N = Move to Next call ID

P = Move to Previous call ID

L = List call ID's in current file

X = Set SP flags

H = Print Help

Q = Quit

Or just enter the ID of the call you want if you know it

Use (N)ext and (P)revious to move between the call ID's

_ss7path_20040116103221.btr contains 1 call(s)

==> Working on call 1 ID 23 H = Help [S/F/D/G/C/A/N/P/L/H/Q/id]?

8. Type Call Id at the prompt in order to jump to the MDL trace of the bad call.

9. Choose option C in order to convert the trace file.

Note: The .btr files are binary trace files that are produced by the PGW tracer function. The main part

of the file name is given in the VSC MML command sta−sc−trc. The PGW always adds a .btr

extension to these files. By using the C option, the file is converted into a text format and the

extension has .trc files that are text trace files. They contain detailed line by line trace information

from the MDO code that is run in the simulation replay that produces the file. Therefore, they contain

MDL traces.

10. The trace file is in /opt/CiscoMGC/var/trace.

Collect the platform.log information under /opt/CiscoMGC/var/log. In some cases the TAC engineer

can ask for other platform.log information related to the problem that is reported while the TAC case

is handled.