Cellular Network Infrastructure » Radio Access Network » OsmoBSC

From 48.049:

If only the New Serial Number IE, and not the Old Serial Number IE, is included in the WRITE-REPLACE message,then the BSC shall interpret the message as a write request, i.e. a broadcast request of a new emergency message without replacing an ongoing emergency message broadcast.

at the same time:

Only one emergency message at the time can be broadcasted in a cell. If a write request is received for a cell where an emergency message broadcast is currently ongoing, the write request is considered as failed, see subclause 7.2.3.

Right now, we unconditionally override any emergency message with the new message, even if no Old Serial Number IE is present. This is a bug. We should fail for those cells.

Note the difference between BSC and BTS level:

• The BSC can receive any number of emergency messages active at the same time
• Each BTS can only handle one at a time