this rather large patch changes the way cells are handled in the SS.
It moves RLC and PDCP entities to the cell map of the SS, such that each cell
has its own entities. This allows to support HO operation, for example,
in which two cells need to send SRB messages.
It also extends most of the syssim interface to include the cell name
in all commands so they can be applied on the specified cell only.
this patch refactors the SDU queuing and dropping policy of the RLC and PDCP layer.
the previous design had issues when packets have been generated at a higher
rate above the PDCP than they could be consumed below the RLC.
When the RLC SDU queues were full, we allowed two policies, one to block on the write
and the other to drop the SDU. Both options are not ideal because they either
lead to a blocking stack thread or to lost PDCP PDUs.
To avoid this, this patch makes the following changes:
* PDCP monitors RLC's SDU queue and drops packets on its north-bound SAP if queues are full
* a new method sdu_queue_is_full() has been added to the RLC interface for PDCP
* remove blocking write from pdcp and rlc write_sdu() interface
* all writes into queues need to be non-blocking
* if Tx queues are overflowing, SDUs are dropped above PDCP, not RLC
* log warning if RLC still needs to drop SDUs
* this case should be avoided with the monitoring mechanism
unfortunately, the rapidjson version shipped with Ubuntu 16.04
doesn't support the GetArray() API so we need to use
normal iterator to loop over the array
extend GW-NAS interface to signal test mode activation.
The method is a noop in the normal GW but is implemented in
the TTCN3 DUT according to TS 36.509 for Mode B
The test TC_9_2_1_1_1 sends a Cell->AddOrReconfigure->Basic message
without a "StaticCellInfo" member. This is used to change SIB1 of
the cell and simulate a different PLMN/TAC in the test.
handle_request_cell_basic() ignored the json message if "StaticCellInfo"
is missing which results in the SIB not being updated (PLMN stays as
00102 for example).
With this patch the SIBs after the json are now parsed even if there
"StaticCellInfo" is missing. A confirmation of the json is not sent
because the test does not seem to expect one in that case.
Related: TC_9_2_1_1_1
this fixes an issue where commands are received out of
order and we are therefore applying configs incorrectly. if
commands include a timinginfo we are now putting the command
on a queue that the SS reads after the start of a new TTI.
the security and cell reconfig commands will be added in another
PR after the AS_security command has been fixed.