Dear Community,
We reached a bit of an challenge with the Nokia BTS support we are working on, so before I make a commit, let me explain what the problem is, hopefully someone has a better idea.
The Nokia BTS does not initiate a LAPD connection for the RSL links even when the BTS finished configuring and testing the TRX units. As the support for the Nokia BTSes was mainly done on the smaller InSite units, this problem did not presented itself, as even after the TRX was reset, the recovery is so fast that it is within the LAPD timeout. But with the bigger macro variant (UltraSite), this issue is now presenting itself: after the BTS is configured via OML, we wait for the CONF_COMPL from the BTS, before we start the RSL bootstrap. Problem is that the BCCH TRX needs a RESET during the bootstrap and compared to the smaller InSite or MetroSite (both are so called "integrated TRX units"), the UltraSite TRX takes 10-15 seconds to be ready, and there is no way for us to know when this happens: no OML messages, no RSL LAPD init triggered by the BTS itself, so nothing to trigger on. And by this amount of time the RSL LAPD times out and the TRX is never bootstrapped.
So at the moment the cheap hacky solution is to just increase the RSL LAPD N203 timer from 4 to 20 seconds, this way the LAPD does not timeout and all the TRXes are bootstrapped properly.
Would this be acceptable for just the Nokia family? Or a configurable reset timer is more preferred, like we already have for the OML part? Please let me know your opinions.
The second thing is more of a suggestion: as the existing Nokia codebase can support much more than just the *Site family (both older and newer units can be supported by the same dialect), I would suggest to rename it to "bts_nokia.c" as the name suggests only the Site family is supported. I personally did not tried it, but if anyone has access to newer (or older) units like a Flexi BTS, Flexi Multiradio and Multiradio10 (all with E1 interfaces) please let me know.
Regards, Csaba