Finally,
all problems regarding LAPD and (IS) Interface Switch seem to have been solved.
Using current openbsc 'master' branch and the openbsc.cfg.rbs2308-4trx in it, I am able to initialize all 9 LAPD links (1x IXU-OML, 4x TRX-OML, 4x TRX-RSL) to the RBS 2308.
The IS configuration can now be done as part of the BTS configuration in the OpenBSC VTY. The config file example configures like follows:
E1/T1 TS 1: IXU-OML, TRX0 (OML+RSL) E1/T1 TS 2: TRX0 TS0..3 E1/T1 TS 3: TRX0 TS4..7 E1/T1 TS 4: TRX1 (OML+RSL) E1/T1 TS 5: TRX1 TS0..3 E1/T1 TS 6: TRX1 TS4..7 E1/T1 TS 7: TRX2 (OML+RSL) E1/T1 TS 8: TRX2 TS0..3 E1/T1 TS 9: TRX2 TS4..7 E1/T1 TS 10: TRX3 (OML+RSL) E1/T1 TS 11: TRX3 TS0..3 E1/T1 TS 12: TRX3 TS4..7
If you want to aggregate the OML+RSL links onto one E1 timeslot, the CON unit has to be used. While you can already enter CON configuration on the VTY, it is not yet sent to the BTS.
What's missing now is the OML bring-up of the TRX + TS (TRXC,RX,TX,TS Managed Objects). After that, it should be ready to go for regular RSL messages.
Regards, Harald