Hello Csaba,

On 12/1/16 11:25 PM, Sipos Csaba wrote:
> Hi,
> 
> Maybe its not completely related, but my experience with Nokia Site is to use 
> full E1 timeslots (64kbit) for RSL and OML signalling, otherwise it is not 
> working, and this is not a Nokia limitation.
> 

Nokia did a different implementation on Abis. I'm hoping to get a Nokia
soon and play with it.

> Just try using:

I can't try it because I don't have a PCM based Ericsson but an IP based
one and I really don't know how to make the openbsc.cfg for that one
since I couldn't find anything in the wiki for it. I was trying to help
Caleb and also understand the OM2000. I worked previously on RAN part
with E/// and we integrated this RBSes with real BSCes and according to
my notes E/// is not using full PCM timeslots (64kbit) exactly. They
have 3 types of LDAP configurations for their Abis to RBS.

- Unconcentrated LAPD
For E1 they leave the full timeslot 0 free for synchronization and
utilize timeslots 1-31. In this mode they use a full timeslot for
signaling to TRU (TRXC) and 2 other full timeslots submultiplexed each
in 4x 16kbit for voice and data. OML(CF) is not mentioned specifically
but it says "TRXC-0 and CF goes together on the same timeslot". The E///
naming TRH (Transceiver Handler) says that is handling all LAPD
signaling, signaling BTS to MS and O&M (CF). For T1 lines there is not
synchronization timeslot used and sync is done from the overall T1 line
so T1 config should start with "timeslot 0".

- Concentrated LAPD
Recommended for 3 or more TRUs. Here TS0 64kbit is for synchronization
in E1 links, TS1 is used as 4x16kbit signaling for the first 4 TRXes,
TS2-9 submultiplexed each in 4x16kbit for traffic, TS10 again 4x
signaling,etc. For T1 the same but no TS0 so config starts with TS0 for
4x signaling links for the first 4 TRXes. Since in this mode you need
also configuration for CON the CF(OML) is added by CON to the same
timeslot as the first 4x TRXes that means TS1.

- Multiplexed LAPD
This is used for small cells and here I made the mistake in my previous
mail saying is "Unconcentrated". This type of config multiplexes TRX
signaling + CF(OML) + BCCH/CCCH + SDCCH8 in one full 64kbit timeslot and
on the second timeslot keeps 2x 16kbit subrates spare.

So in the end I am still not sure how the config should look like to
have a PCM based RBS working with OpenBSC.

> And don't forget to configure the BTS Abis allocation accordingly!
> 
> Also for DAHDI, you will need to use the correct config with CCS signalling. 
> This is an example for the system.conf for an E1 based BTS:
> 
> span=1,0,0,ccs,hdb3,crc4    
> bchan=1-31
> 

Thanks for config.

> Regards,
> Csaba
> 

Regards,
Razvan

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