This library is intended to collect all generic/common funcitionality
of all Osmocom.org projects, including OpenBSC but also OsmocomBB
The library currently includes the following modules:
bitvec, comp128, gsm_utils, msgb, select, signal, statistics, talloc, timer,
tlv_parse, linuxlist
msgb allocation error debugging had to be temporarily disabled as it depends on
'debug.c' functionality which at the moment remains in OpenBSC
Some NM attributes are defined differently depending on
the BTS type. Having one big nm_att_tlvdef[] table for
all BTS types is no longer sufficient. This patch
* introduces 'struct gsm_bts_model' to describe a BTS model
* adds definitions of gsm_bts_model for BS-11 and nanoBTS
* changes the abis_nm_tlv_parse() function: include a bts pointer
Theses will be useful to know if we can reuse the tuples or if
we should renew. The 'issued' is currently purely informative.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
* On start the vty code will call the abis_nm method and this
will set the administrative state to unlock/lock
* During startup the BTS will report its state as well and would
possible overwrite the set administrative. We are only going
to update the administrative if it was 0 before. This appears
to work on all of my tests. In case this will not be the case
for others we will have to split the administrative into two
sets one for the BTS and one for the BSC.
In many cases we actually want a name / unique ID for the lchan,
not just for the on-air timeslot... especially in SDCCH/8 case,
where 8 SDCCHs share one timeslot...
When we allocate a channel, we send the RSL CHAN ACT REQ and wait until we get
a CHAN ACT ACK. Only the ACK will change the state, so there is a race where
we allocate that same channel to a different channel request before we get
the ACT ACK.
Introducing a new ACT_REQ state resolves this issue.
This has the advantage that counters can be added all over the code
very easily, while having only one routine that stores all of the
current counter values to the database. The counters are synced
every 60 seconds, providing relatively fine grained statistics
about the network usage as time passes by.
This implements the handover algorithm (and associated parameters)
as described in Chapter 8 of the book "Performance Enhancements in
a Frequency |Hopping GSM Network" by Thomas Toftegard Nielsen and Jeroen
Wigard.
The parameters such as averaging windows are configured in struct
gsm_network. We keep some state to trakc up to 10 neighbors as
they are being reported from the MS.
This has so far only been tested in a network with two BTS that
have each other as neighbor. Networks with morge neighbors might
encounter bugs.
This allows us to block packets that we have received after the channel
is no longer being used. This is visible during handover, where we still
receive a measurement report after the MS has switched to the new channel.
This leftover measurement report then attempts to trigger another handover,
which si bogus and will fail - and thus only consumes resources.
With the new LCHAN_S_ACTIVE state, we can check for this when processing
the measurement report.
We will need this for the actual handover algorithm implementation, as we will
only know the current BTS and the BCCH ARFCN of the strongest cell in the
measurement reports. Using this new function, we can resolve the matching
gsm_bts.
We use a 1024-bit-sized bitvec to generate the BA and neighbor frequency list.
This bitvec is still generated from the list of all BTS's inside the BSC, but
this patch is the first step to generalize this, i.e. generate arbitrary
neighbor lists.
With ip.access, in case of TCH/H, we have one RTP stream for each half-slot
(lchan), not just one per on-air timeslot. This is quite different from
a classic BTS where the TRAU frames of the two TCH/H channels would be
part of the same 16k sub-slot in a E1 timeslot.
Before this commit, OpenBSC used templates for the SYSTEM INFO
1, 2, 3, 4, 5 and 6 messages. Those templates were patched in
various places to reflect the network config like ARFCN.
Now, we actually generate those SI messages ourselves, using
values from the configuration file, and even calculating neighbor
cell lists.
All bts'es that you have configured in OpenBSC will end up in
the neighbor cell list - which should be more than sufficient for
the current small-single-site networks.
- Make sure that on runtime the Radio Carrier can be
locked and unlocked. The vty code calls into the
Abis NM to lock/unlock the channel and the state is
stored there.
- Make sure that on start the Radio Carries remains
offline and we are not starting it. On start the
radio carrier is either locked or unlocked. This means
the RSL will not connect until the RF is unlocked. It
will connect then. To see RSL bringup failures one
needs to parse the RSL nack message.
- When the TRX is locked on startup the RSL link will
only be established after it will be unlocked.
Both GSM 04.08 RR and GSM 08.58 RSL need the multirate config
in the channel modify. Place the config in the lchan, change
the gsm48 methods to not take the argument, change the RSL
implementation to make use of it with the right IE.
The other code should use the t(l)v_put routines as well but
were left untouched for now.
Keep track of which SAPIs have been established either by the
BTS (from the MS) or by us. This can be used by the on-waves
BSC code to figure out if a new request should be made.
Supporting GPRS means we have a number of additional OML objects to
deal with. We need to extend our gsm_bts structure to at least
include the nm_state for each of those objects.
Add support for 1900 nanoBTS by using unified bts_type
GSM_BTS_TYPE_NANOBTS for 900, 1800 and 1900 versions.
Reduce the nanoBTS enum values to one and derive the
version from the user supplied band. In the future we
might want to do auto band detection.
The configuration file needs to be changed to refer
to nanobts instead of nanobts900/nanobts1800.
Signed-off-by: Mike Haben <michael.haben@btinternet.com>
Signed-off-by: Holger Hans Peter Freyther <zecke@selfish.org>
Harald Welte
Sylvain Munaut
Harald Welte