Mig Decoder

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Mig Decoder

Post  Admin on Wed Feb 24, 2010 10:09 am

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Purpose



MicDecoder is mainly used to decode A and Abis information. One message is showed in one line, so it's easier for the user to have an overview. If
the source file offers enough information, the decoder can qualify the
IMSI, so only one subscriber’s behavior will be showed.


MicDecoder
is not a full function protocol analyzer, it only provides some
important information on A and Abis interface, and gives the user some
idea of what happen. Not all the information element in the message will be decoded. How much information it can offer largely depends on the source file. The source file comes from the restart data or TEST SYSTEM in BSC. Due to the restriction of the TEST SYSTEM, it's impossible to trace all the A and Abis information in the live site. To use it in live site, more condition should be set in the TEST SYSTEM in order to get useful trace file. So the user's skill of TEST SYSTEM is needed.


MicDecoder supports online decoding, it’s quite usefully feature. Reversion history



2006-04-10 Version 1.0, for test purpose.

2006-05-17 Version 1.1, add the support to decode the trace from R11 and R12, correct some document fault.

2006-07-13 Version 06.0713, correct the serious fault during IMSI qualification, add the support for G2U handover

2006-07-22 Version 06.0722, correct the fault during IMSI qualification, and a memory leak.

2006-10-20 Version 06.1020, add basic support on SCCP CL messages.

2006-10-23 Version 06.1023, add basic support on supplementary service.

2006-12-20 Version 06.1220, add support on system information, correct fault in decoding message of R12 format.

2006-12-31 Version 06.1231, add basic support on Abis OML messages.

2007-01-31 Version 07.0131, add support on DTM messages.

2007-07-09 Version 07.0709, compile the program on Visual Studio 2005 platform, some user friendly functions are added.

2007-10-24 Version 07.1024, add support on signal function fetched from PLEX.

2008-01-13 Version 08.0113, online decoding is supported.
How to use



Offline Decode 1. Source file generation



Two source files can be recognized by MidDecoder.

One is the restart data from live site, which may contains some traffic information.

Another comes from the trace result of TEST SYSTEM. In order to get the trace file, please put in the following trace in the TEST SYSTEM.

To trace call flow in R8, R9 and R10, use the trace below:

TELMI:TI=50,LOAD=80;
TMSIZE 32768;
ON IN DO:P MS,P EXECFID,P SWD,;
ON OU DO:P MS,P EXECFID,P SWD,;
ON IN RMHBI RCRECABISMSGC,RCRECABISMSGI,RCCHALLINFO;
ON OU RMHBI RCSENDABISMSGC,RCSENDABISMSGI,RCSNDABISMSGC10;
ON OU RMHAIUL RACOSENDINMSG1C,RACOSNDBSSMAP1C,RACOSNDBSSMAP1I,RACOSENDDTAP1C, RACOSENDDTAP1I;
ON OU RMHAIUL RACOINMSGRSP1C,RACOINMSGRSP1I,RACOINMSGREJ1C;
ON IN RMHAIDL RACOTAKEBSSMAPC,RACOTAKEBSSMAPI,RACOTAKEDTAPC,RACOTAKEDTAPI, RACOTAKEINMSGC,RACOTAKEINMSGI;
INIT;

To trace call flow in R11, R12 and 06A/06B/07A/07B, use the trace below:

TELMI:TI=50,LOAD=80;
TMSIZE 32768;
ON IN DO:P MS,P EXECFID,P SWD,;
ON OU DO:P MS,P EXECFID,P SWD,;
ON IN RMHBI RNRECABISMSGC,RNRECABISMSGI,RNALLOCINFO;
ON OU RMHBI RNSENDABISMSGC,RNSENDABISMSGI,RNSNDABISMSGC10;
ON OU RMHAIUL RACOSNDBSSMAP1C,RACOSNDBSSMAP1I,RACOSENDDTAP1C, RACOSENDDTAP1I,RTCOSNDINAMSGC;
ON IN RMHAIDL RACOTAKEBSSMAPC,RACOTAKEBSSMAPI,RACOTAKEDTAPC,RACOTAKEDTAPI, RTCOTAKEINMSGC,RTCOTAKEINMSGI;
INIT;

To trace SCCP CL message in R8, R9 and R10:

TELMI:TI=50,LOAD=80;
TMSIZE 32768;
ON IN DO:P MS,P EXECFID,P SWD,;
ON OU DO:P MS,P EXECFID,P SWD,;
ON IN RABDI RACLSENDDATA1C, RACLSENDDATA1I;
ON OU RABDI RACLTAKEDATAC, RACLTAKEDATAI;
INIT;

To trace SCCP CL message in R11, R12 and R06A/06B/07A/07B:

TELMI:TI=50,LOAD=80;
TMSIZE 32768;
ON IN DO:P MS,P EXECFID,P SWD,;
ON OU DO:P MS,P EXECFID,P SWD,;
ON IN RABDI RTCLSENDADATAC, RTCLSENDADATAI;
ON OU RABDI RTCLTAKEADATAC, RTCLTAKEADATAI;
INIT;

To trace system information (halt and activate the cell can trigger it):

TELMI:TI=50,LOAD=80;
TMSIZE 32768;
ON OU DO:P MS,P EXECFID,P SWD,;
ON OU RCSI RHSENDMSGC;
INIT;

To trace Abis OML message (RBS2000):

TELMI:TI=50,LOAD=80;
TMSIZE 32768;
ON OU DO:P MS,P EXECFID,P SWD,;
ON IN DO:P MS,P EXECFID,P SWD,;
ON OU RXOLH RHSENDMSGC, RHSENDMSGI;
ON IN RXOLH RHRECMSGC, RHRECMSGI;
INIT;

To
trace a single call flow in live site is very difficult, IMSI can be
used as the filter to qualify the trace, and the trace below can be a
reference (it’s not valid for those sites with TMSI using), the
position of IMSI vary in different scenarios, message
RACOSENDINMSG1C should be studied carefully:

TELMI:TI=50,LOAD=80;
TMSIZE 32768;
ON IN DO:IF BNR=H'9E THEN;
IF DR12 MASK H'FFF0=H'0640; !qualify IMSI 460002200000012!
IF DR13=H'2200; !qualify IMSI 460002200000012!
IF DR14=H'0000; !qualify IMSI 460002200000012!
IF DR15=H'2100; !qualify IMSI 460002200000012!
SET TVAR 0=EXECFID;
P EXECFID,P MS,P IA,P SWD;
ELSE;
IF TVAR 0=EXECFID;
P EXECFID,P MS,P IA,P SWD;
FI,;
ON OU DO:IF TVAR 0=EXECFID,P EXECFID,P MS,P IA,P SWD,;
ON IN RABDI RACOSENDINMSG1C;
ON IN RMHAIDL RACOTAKEBSSMAPC,RACOTAKEBSSMAPI,RACOTAKEDTAPC,RACOTAKEDTAPI, RACOTAKEINMSGC,RACOTAKEINMSGI;
ON OU RMHAIUL RACOSNDBSSMAP1C,RACOSNDBSSMAP1I,RACOSENDDTAP1C, RACOSENDDTAP1I;
ON OU RMHAIUL RACOINMSGRSP1C,RACOINMSGRSP1I,RACOINMSGREJ1C;

save the file with any name, and put it under certain directory, i.g. \DATA.

It's
suggested create a directory and put all the trace files there, the
result file will be saved in the same directory as the trace file.


The
trace above can be used in STP without any problem, however more
restriction is needed in live site, otherwise it's hard to get the
useful information. To the worse, it may cause the system unstable.

2. Target file generation



Once
the source file is ready, run MicDecoder, and open the source file in
MicDecoder. A and Abis raw data and decoded information will be showed.


To make it easier to study, filters can be used. There are some filters in MicDecoder:

  • IMSI/TMSI filter: to qualify the MS with the specific IMSI/TMSI, it makes sense only when enough information is collected. Normally it’s useless for the log file collected from live site
  • A message filter: qualify A interface message
  • Abis message filter: qualify Abis interface message, including RSL and OML
  • MS filter: show or hide time information
  • EXECFID filter: show or hide forlopp information
  • Raw Data filter:
    show or hide raw data, it could be useful that if the decoder can not
    decode the message, user can decode it by himself/herself.



It
could be useful that original information is showed as well as the
decoded information (especially when the source file is restart data). This can be set from menu
à View à Original Info, however it must be done before source file is opened.

The result file can be saved, by default it will be saved under the same directory as source file.

Online Decode

This function is only tested with WinFiol version 7.0

1. Trace generation

Put the trace into WinFiol, the trace is referred to the above (Source file generation, Offline decode), or any other trace.

2. Decode generation

In MicDecoder, two steps are needed:

  • Connect MicDecoder to WinFiol, Menu à WinFiol à Connect, notice the status bar in MicDecoder, it shows “WinFiol is connected” when ready.
  • Connect MicDecoder to current active channel in WinFiol, Menu à WinFiol à Connect Current Channel, notice the status bar in MicDecoder, it shows “Connected to channel #x …” when ready.


After
that, when there is signal information showed on the WinFiol, the
decoded information will show up on MicDecoder at the same time.


To end the online decoding:

  • Menu à WinFiol à Disconnected, notice the status bar in MicDecoder, it shows “WinFiol is disconnected” when ready.


Decode signal function

It
can be useful to get the signal function sometimes, especially when the
user is familiar with signal flow, it give the user an overview.


To
make it work, Plex database should be connected to the MicDecoder, then
signal function will be fetched and showed with the original
information, to make it work, follow the step below:



  • Connect plex database, Menu à View à Set plex database
  • Tick signal function, Menu à View à Signal Function
  • Tick original information, Menu à View à Original info
  • Open log file

User friendly function



MicDecoder is not good at text edition. It just offers some basic function like Find, Select, Copy, Paste etc. To get the information further processed, it’s suggested to use other powerful editor like UltraEdit etc.
What’s the benefit



In MidDecoder, one message is showed in one line, so it's easier for the user to have an overview. With enough information, it can qualify single subscriber behavior. This tool is very useful in STP testing, and it can take the place of protocol analyzer to some extend. The log file collected from STP can be used as the reference in trouble shooting later.

MicDecoder
supports online decoding, as long as connection between MicDecoder and
WinFiol is setup, the signal trace showed on the WinFiol will be
decoded and showed up in MicDecoder at the same time.


Due
to the restriction of TEST SYSTEM, it may not be very useful in live
site, however with the good skill in TEST SYSTEM, setting proper
condition, it sill valuable for trouble shooting.


MicDecoder can decode traffic information in restart data as well. This could be quite useful when analyzing some traffic related fault in live site. It has been used in emergency and CSR handling and offer useful tips for trouble shooting.
Restriction



MicDecoder can not decode the entire information element in the message. Only some important information is showed. As for which information element is important, it's judged by the author.

IMSI/TMSI
filter doesn’t work properly after mobile handover (A interface message
can still be filtered, but not for abis message), so if handover
happens in the log file, the user must filter the message by
himself/herself.


Not
all the message can be decoded, once you find out certain message in
your trace file can not be decoded, please feedback the author.


VGCS message is not supported for time being, since there is not log files caught so far. If anyone of you have chance to collect VGCS log, please send a copy to author.

The following A and Abis messages in the trace file will not be handled in current version. However they are seldom used (long message is often seen in SMS or Handover Request).

For R8, R9 and R10:

A interface:
RACOSNDBSSMAP1S, RACOSNDBSSMAP1E
RACOSENDDTAP1S, RACOSENDDTAP1E
RACOINMSGRSP1E
RACOTAKEBSSMAPS, RACOTAKEBSSMAPE
RACOTAKEDTAPS, RACOTAKEDTAPE
RACOTAKEINMSGS, RACOTAKEINMSGE

Abis interface:
RCRECABISMSGS, RCRECABISMSGE
RCSENDABISMSGS, RCSENDABISMSGE

For R11 and R12:

A interface:
RACOSNDBSSMAP1S, RACOSNDBSSMAP1E
RACOSENDDTAP1S, RACOSENDDTAP1E
RACOINMSGRSP1E
RACOTAKEBSSMAPS, RACOTAKEBSSMAPE
RACOTAKEDTAPS, RACOTAKEDTAPE
RACOTAKEINMSGS, RACOTAKEINMSGE

Abis interface:
RNRECABISMSGS, RNRECABISMSGE RNSENDABISMSGS, RNSENDABISMSGE

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