16 Jun
2009
16 Jun
'09
3:13 p.m.
Hello friends,
I want to modify the SYSTEM INFORMATION data, but I have some
difficulties to understand the GSM spec.
It's about the GSM 04.08 part 10.5.2.34, I don't know how to interpet
table 10.5.72 (and other similar tables).
According to paragraph 9.1.35 table 9.32 (GSM 04.08) SI3 rest octetets
has a length of 4 bytes, but according to par. 10.5.2.34 we're dealing
with a type 5 IE and thus with length of 5 bytes. That's odd to me, but
hey, the world is full of surprises :)
Anyway, the problem is I don't know how to interpret table 10.5.72 (of
GSM 04.08). I mean, for example, element CBQ (Cell Bar Qualify) is at
bit 1. Bit 1 of what, which octet? What is L | H? Can someone explain it
to me, so I can experiment with SI messages?
Thank you!
18 Jun
18 Jun
4:12 p.m.
Well guys,
If someone can help me with how to fill in the Rest Octets, I'll send
you a postcard from my city to thank you :)
What I found out is that it uses CSN.1 notation, but the description is
hard to follow, I began to see words floating around the screen.
<SI3RestOctet>::=<Optionalselectionparameters>
<OptionalPoweroffset>
<SystemInformation2terIndicator>
<EarlyClassmarkSendingControl>
<Schedulingifandwhere>
{L|H<GPRSIndicator>}
<sparepadding>:
<OptionalSelectionParameters>::= L |H <SelectionParameters>;
<SelectionParameters>::=
<CBQ:bit(1)>
<CELL_RESELECT_OFFSET:bit(6)>
<TEMPORARY_OFFSET:bit(3)>
<PENALTY_TIME:bit(5)>;
<OptionalPowerOffset>::= L |H
<PowerOffset:bit(2)>;<SystemInformation2terIndicator>::=
L|H;
<EarlyClassmarkSendingControl>::= L|H;
<Schedulingifandwhere>::= L|H <WHERE:bit(3)>;
<GPRSIndicator>::= <RACOLOUR :bit(3)>
< SI13POSITION :bit>;
So, now I want to enable GPRS support by do something with
GPRSIndicator. This is how I thought to do that:
L|H -> 1
next -> RACOLOUR -> 000
next -> SI13POSITION -> 0
So we get -> 1 000 0
Next step is to do something with padding but than I'm lost. I don't
have good documentations on how to use CSN.1 for GSM network.
4:59 p.m.
Nordin -
You will probably find GSM 04.07 Appendix B of some use here.
Specifically, for a description of the padding sequence and the
meaning of "H" and "L" see GSM 04.07 B.1.2.2.
-- David
On Jun 18, 2009, at 9:12 AM, Nordin wrote:
Well guys,
If someone can help me with how to fill in the Rest Octets, I'll
send you a postcard from my city to thank you :)
What I found out is that it uses CSN.1 notation, but the
description is hard to follow, I began to see words floating around
the screen.
<SI3RestOctet>::=<Optionalselectionparameters>
<OptionalPoweroffset>
<SystemInformation2terIndicator>
<EarlyClassmarkSendingControl>
<Schedulingifandwhere>
{L|H<GPRSIndicator>}
<sparepadding>:
<OptionalSelectionParameters>::= L |H <SelectionParameters>;
<SelectionParameters>::=
<CBQ:bit(1)>
<CELL_RESELECT_OFFSET:bit(6)>
<TEMPORARY_OFFSET:bit(3)>
<PENALTY_TIME:bit(5)>;
<OptionalPowerOffset>::= L |H <PowerOffset:bit(2)
David A. Burgess
Kestrel Signal Processing, Inc.
;<SystemInformation2terIndicator>::=
L|H;
<EarlyClassmarkSendingControl>::= L|H;
<Schedulingifandwhere>::= L|H <WHERE:bit(3)>;
<GPRSIndicator>::= <RACOLOUR :bit(3)>
< SI13POSITION :bit>;
So, now I want to enable GPRS support by do something with
GPRSIndicator. This is how I thought to do that:
L|H -> 1
next -> RACOLOUR -> 000
next -> SI13POSITION -> 0
So we get -> 1 000 0
Next step is to do something with padding but than I'm lost. I
don't have good documentations on how to use CSN.1 for GSM network.
6:18 p.m.
On Thu, Jun 18, 2009 at 06:12:38PM +0200, Nordin wrote:
Well guys,
If someone can help me with how to fill in the Rest Octets, I'll send
you a postcard from my city to thank you :)
What I personally imagine might help is to look at the BSSMAP dissector in
wireshark. It typically contains quite easily readable C-code for the
actual packet parsing.
--
- Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/
============================================================================
"Privacy in residential applications is a desirable marketing option."
(ETSI EN 300 175-7 Ch. A6)
8:15 p.m.
What I personally imagine might help is to look at the BSSMAP dissector in
wireshark. It typically contains quite easily readable C-code for the
actual packet parsing.
Ok, I'll look at it this weekend. I haven't used wireshark a lot, but this
is the right time to learn to work with it. Also to analyze your trace you
post me about listening to neigbourcells with nanobts.
5490
days inactive
5492
days old
5 comments
4 participants
participants (4)
-
David A. Burgess -
Harald Welte -
Nordin -
Nordin Bouchtaoui