Cellular Network Infrastructure » Radio Access Network » OsmoBTS

When no SI 2bis, nor 2ter, nor 2quater is in use, then the code in bts_sysinfo_get() will return null, causing the transmission of a dummy frame (0303012B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B) instead of a system information message. This is - at least - very odd and might not be backed by the specification. We should simply send any other system information message instead of sending a frame that does not have a valid SI header.

While 030301 might be a valid, empty UI frame on a DCCH, it is not a valid frame for the BCCH, where the header is structured differently.

In fact, bts_sysinfo_get() should never return NULL and always return a valid BCCH message.

This bug was found while developing http://git.osmocom.org/osmo-ttcn3-hacks/tree/sysinfo/Test.ttcn