be more efficient in batching IMMEDIATE ASSIGN REJECT messages
The RR Immediate Assignment Reject message can handle up to fourr identities that are rejected in a single message.
We currently use one message per identiry, wasting downlink AGCH capacity.
I think this feature is relevant particularly in cases where many
REJECTs are expected, i.e. where many phones are around that are not
permitted to join. Think of a private/small GSM networrk in an area
where there is no (good) public network coverage, but where lots of
regular subscribers of the other operators pass by. Or in situations
where the public network fails, forcing all the phones to try to
register on the private/small network running OpenBSC.
- we waste one entire 23 byte MAC block for rejecting only a single subscriber
- We don't scale the AGCH up by means of BS_AG_BLKS_RES
Both of the features above would enable rejecting more phones (with
permanent reject cause) ensuring they don't overload RACH+AGCH on the