Hi Sylvain,
thanks for reproducing the GPRS setup, it is always useful to know
it works for other people, too.
On Thu, Jun 10, 2010 at 09:47:08AM +0200, Sylvain Munaut wrote:
I tried the gprs yesterday, and in the end, it worked
quite well
albeit slow (but that's GPRS I guess :p)
You can cofigure multiple timeslots as PDCH. It will work transparently
as the load distribution is done by the BTS alone.
I'm happy (though surprised) it worked for you fine. The biggest problems
at the moment are
* no defragmentation of fragmented SNDCP PDU's in the MS->network direction
* lack of BSSGP flow control (implementing it right now)
I had to fix a couple of crashes (both of SGSN and of
the BTS, the
latter being due to malformed packets) and the fixes are in my
sylvain/pending branch.
I'm happy to look at them.
Also, a couple of 'gotcha' I hit for future
reference:
- Even if running on the same machine, the SGSN & GGSN GTP interfaces
need to have different IPs or they'll try to bind to the same ports
and fail.
Yes, that is almost expected. We could add config options to bind to
non-standard ports to fix this - but at the cost of having to manually
click 'decode as...' every time in wireshark.
- Using 'TCH/F_PDCH' channel config
doesn't work (that's what I used
with the old gprs branch a long time ago). You need to use 'PDCH'
This is true and known. a TCH/F_PDCH combination will need an explicit
ip.access proprietary RSL "PDCH ACTIVATE" message, and although I have
written some code for dynamic PDCH/TCH_F allocation in OpenBSC, this
has never been tested (and i believe it's out of the master branch).
Finally a list of the IPs in the configuration and
what they mean (I
stumbled a little when trying to setup all those :):
It would be great if you could work on an article on the wiki how to
set this up. The configuration/vty commands should be stable and I
don't expect this to change anymore.
--
- Harald Welte <laforge(a)gnumonks.org>
http://laforge.gnumonks.org/
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