We cannot support in-call handover of calls without a RTP proxy,
since at the time of the handover the SSRC, sequence number and
timestamp of the RTP frames change.
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.
In order to support multi-TRX configurations, we need to be able
to cope with multiple RSL streams (each with their own stream identifier)
inside one ip.access TCP connection.
Since this is very similar to using the TEI on a E1 line, we simply
recycle the logic and data fields that are used for the TEI.
We are using LAC=0 for remembering that a GSM subscriber is
detached. I recently added code to gsm_bts_by_lac that will
return every BTS in case the lac is 0. Harald highlightes
that we would now search for detached subscribers at every
BTS of our network which is clearly not what we want.
Introduce two defines for the two reserved LAC, add a
pointer to the specification, check that our config files
do not contain these reserved values, use the define
and change gsm_bts_by_lac to use the other define.
The LAC can be 16bit of size. the generation of the LAI, struct
gsm_subsriber and the BSC<->MSC was already using it as a
16bit (short) value.
Change struct gsm_bts to parse 16bit and change the vty configuration
parsing code to deal with a short too.
Transfering the cell_identity from BSC to MSC is required for the
on-waves.com support. Allow to set the cell_identity in the cfg
file and patch the system information tables to set it.
tmsi is four octets long, there is no need to make it a string
and then jump through hoops to convert it to a number. Keep the database
using it as a string to benefit from the NULL handling of the db.
Introduce the reserved tmsi which has all bits set to 1 according
to GSM 03.03 §2.4 and start checking for it and make sure the db
code will never allocate such a tmsi.
You can now type commands like
'sms send extentsion 1003 This is a test message'
to trigger paging and delivery of the message 'This is a test message'
to the subscriber with extension 1003. There's also a variant that uses
the IMSI of the subscriber.
Messages sent this way are only attempted to deliver immediately. If
immediate delivery fails, there is no attempt to store it in the database.
we now have the full path from the MS into the database (SUBMIT), as well as
back from the database to the MS (DELIVER). The database gets correctly
updated once a SMS has been successfully delivered.
What's still missing is the periodic scan over all undelivered messages,
trying to deliver them to the respective MS. So far, you have to manually
trigger this on the telnet interface with 'sms send pending 1'
Harald Welte
Harald Welte