Idea for synchonous logging/review of debug + GSMTAP

Alexander Chemeris alexander.chemeris at
Tue Jan 29 12:37:38 UTC 2013

On Tue, Jan 29, 2013 at 4:33 PM, Harald Welte <laforge at> wrote:
> Hi Alexander,
> On Tue, Jan 29, 2013 at 04:11:26PM +0400, Alexander Chemeris wrote:
>> Yes, debugging PCU is PITA and we've been discussing logging
>> improvements with Ivan for some time already. From our discussions it
>> seems that the biggest issue is to correlate log messages with the
>> actual user and/or session. How do you want to solve this issue with
>> the GSMTAP?
> I would treat those two independent.  The case for GSMTAP is simply to
> have a synchronous / monotonic log (pcap in this case) that combines
> both actual packets on Gb and Um, as well as the human-readable log
> messages generated by the PCU code in between.

Just to clarify. Do you just want to transfer a normal log string as a
payload in a GSMTAP message, so that it'll be shown in Wireshark
"Info" column?

> As for the human-readable PCU log messages, I would suggest something
> like pre-fixing all of them with the TLLI in the beginning like
> [1a2b3d4e] at the start of every line.  I would guess that for most of
> the log messages, the TLLI to which they relate should be known.  The
> same is not the case for other identifiers like the IMSI.

I'll let Ivan comment on that. My knowledge is somewhat lacking in this area.

Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио

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