When looking at GSMTAP output so far, one is easily overwhelmed by way
too much information being presented. A lot of is consists of DUMMY
frames, which are probably of lowest interest, ever.
A concept similar to the "gsmtap-sapi" of OsmoBTS is introduced, by
which the user can configure which particular categories (uplink or
downlink control or data, gprs or egprs, ...) he actually wants to
see in his logs.
Change-Id: I297183690e98a7234dfc1608c18847d8981306e4
Fix error introduced in 1275a3f91a by
using signed 32 bit integer which is enough for Frame Number in
GSM. Also, mark parameter constraints more explicitly:
- add assert for expected FN values
- don't perform computation for non-relative FN
The error was:
bts.cpp: In member function ‘uint32_t BTS::rfn_to_fn(uint32_t)’:
bts.cpp:554:25: error: call of overloaded ‘abs(uint32_t)’ is ambiguous
if (abs(rfn - m_cur_rfn) > RFN_THRESHOLD) {
^
In file included from /usr/include/c++/6/cstdlib:75:0,
from /usr/include/c++/6/stdlib.h:36,
from /usr/include/osmocom/core/linuxrbtree.h:97,
from /usr/include/osmocom/core/timer.h:35,
from ./bts.h:29,
from bts.cpp:21:
/usr/include/stdlib.h:735:12: note: candidate: int abs(int)
extern int abs (int __x) __THROW __attribute__ ((__const__)) __wur;
^~~
In file included from /usr/include/c++/6/stdlib.h:36:0,
from /usr/include/osmocom/core/linuxrbtree.h:97,
from /usr/include/osmocom/core/timer.h:35,
from ./bts.h:29,
from bts.cpp:21:
/usr/include/c++/6/cstdlib:185:3: note: candidate: __int128 std::abs(__int128)
abs(__GLIBCXX_TYPE_INT_N_0 __x) { return __x >= 0 ? __x : -__x; }
^~~
/usr/include/c++/6/cstdlib:180:3: note: candidate: long long int std::abs(long long int)
abs(long long __x) { return __builtin_llabs (__x); }
^~~
/usr/include/c++/6/cstdlib:172:3: note: candidate: long int std::abs(long int)
abs(long __i) { return __builtin_labs(__i); }
Change-Id: Ib6d895a97aa35414f245ea4406c6e78f1b4fb5b8
The implementation of the method rcv_rach() in class BTS, restores
the absolute frame number of the incoming RACH-Request by using
the relative frame number (RFn = Fn mod 42432) from the rach
request and the already known internal absolute frame number
m_cur_fn, which is continusly updated by the CCU interface.
In some rare cases, a RACH request might be received by the BTS,
a very short time before the frame number wraps in its 42432.
Depending on the PCU location, RACH request might be received
by the BSC, which forwards it to the PCU. It is then likely
that, while the RACH request is being forwarded to the PCU, the
PCU internal absolute frame number wraps before the RACH
can be processed. The relative frame number from the rach
request would then be interpreted as if it were received after
the wrapping of the internal frame number modulos.
This commit adds logic to detect and resolve this race condition.
Also a unit test is added to check some cornercases.
Change-Id: I74f00c11e5739d49f370ce6c357149e81d9aa759
Array indexing mismatch is corrected for SPB counters.
(bts_ctr_description with the bts counter declaration).
Change-Id: I9b17ca0f838a37d9405cebf2319e722a302f5ed9
Adds spb counters at BTS level(show bts statistics).
Adds RLC/MAC downlink control msg at ms level(show ms imsi <imsi_val>).
Adds the number of coding schemes counter for UL at TBF level.
Change-Id: Icbe4ba95e34bea89ee36f532d099db68204b7c38
Separate qbit-TA to TA conversion into separate function and use it for
computing and updating Timing Advance.
Note: the code was tested with TA=0 only to make sure it does not
introduce regressions.
Change-Id: I96fdbb20b09fb85fdd9fb6dcf3c25f6bee7f80e4
Fixes: OS#1531
Interface structure between osmo-bts and osmo-pcu is updated with
the parameters to differentiate the type of RACH and further
support 11 bit RACH. The function prototype and definitions are
changed accordingly. Interface version number is increased.
Change-Id: I265c2d92d36d6cbcbeee60cdd8407dafe1da06a4
Modify the header files with necessary data structure to handle
Split block for EGPRS DL TBF.
The EGPRS resegmentation feature allows PCU to retransmit
RLC blocks of HeaderType1, HeaderType2 by segmenting
them to 2 HeaderType3 blocks(Example MCS5 will be
retransmitted as 2 MCS2 blocks). Table 10.4.8b.2 of 44.060
explains the possible values of SPB in HeadrType3 for DL
direction. The PCU decides to retransmit the
blocks by resegmenting it based on Table 8.1.1.1 of 44.060.
The retransmission MCS is calculated based on current MCS of
the Block and demanded MCS by PCU. Section 10.3a.3.3 of 44.060
shows the HeadrType3 with SPB field present in it
Change-Id: I57673e53a9da2affa7e8aaa6551ac4b271c3d525
Function is added to parse the EGPRS header type 1 in uplink tbf path.
along with configuration parameter updation to reflect max mcs in UL
Change-Id: I13c250e2e07377982ac3f29745f3cffd4088552a
Reviewed-on: https://gerrit.osmocom.org/270
Reviewed-by: Harald Welte <laforge@gnumonks.org>
Tested-by: Jenkins Builder
rlc_sent_dummy count the amount of dummy package which are
sent in case no data packet is in the queue.
Change-Id: Ia60eab853d9145980f30d63e4ce4b520b8c51381
Reviewed-on: https://gerrit.osmocom.org/85
Tested-by: Jenkins Builder
Reviewed-by: Holger Freyther <holger@freyther.de>
This option allows user to use custom IP address instead of default "localhost".
Correspondingly gsmtap init moved from sysmoBTS-specific code up to "bts" struct
level. This way it can be easier reused by other implementations. The
lack of regressions was verified by checking following command on
sysmoBTS: "./osmo-pcu -c osmo-pcu.cfg -r 1 -i 192.168.10.1" where
192.168.10.1 is the host which was running wireshark and netcat:
"nc -u -l 192.168.10.1 -p 4729" to accept gsmtap flow.
Currently the window size is fixed to 64 even for EGPRS.
Support dynamic window sizes depending on the number of PDCH. The
WS can be set to b + f * N_PDCH. If the result is not valid according
to TS 44.060, Table 9.1.9.2.1, the value will be corrected to use the
next lower valid value (or 64).
The following VTY commands are added (config-pcu node):
window-size <0-1024> set base (b) value and leave f unchanged
window-size <0-1024> <0-256> set base (b) and factor (f)
Sponsored-by: On-Waves ehf
Currently gprs_rlc_ul_window and gprs_rlc_dl_window are completely
separate classes, containing several identical members and methods.
This commit add a shared parent class containing WS and SNS handling.
Sponsored-by: On-Waves ehf
Currently the plain 'egprs' command enables EGPRS but doesn't prevent
phones from being served in GPRS mode if they do not support EGPRS.
This involves complex frame allocation implementations in dynamic
mode, especially if 8PSK is being used. This is due to the inability
of non-EGPRS phone to decode 8PSK USF and ES/P altogether. Since
polling has a higher priority than USF, collisions will have to be
prevented by the PCU by never using an GPRS USF if it refers to a FN
that is already being used for polling.
This commit just disables mixed usage by ignoring GPRS-only request
if EGPRS is enabled.
The following VTY command (config-pcu node) is changed:
egprs -> egprs only
Sponsored-by: On-Waves ehf
Currently this message is ignored.
Support decoding and handling of this message. Use a bitvec for the
decoder that just represents a BSN sequence without any encoding
details (first bit -> first BSN). Return the corresponding BSN range
(snsmod(bsn_begin + bits_in_bitvec) = bsn_end), so snsmod(bsn_end-1)
is the last BSN if there is at least 1. If bsn_begin == bsn_end, no
BSNs has been added.
Note that this bitvec is not yet used for RBB handling. It just calls
the old rcvd_dl_ack with a faked (all bits are 1) RBB map.
Sponsored-by: On-Waves ehf
Provide the initial MCS values for EGPRS data blocks. They are set
to 1 (MCS-1) for each direction and there is no support to change
these configuration values yet (the automatic adaption still works,
so there is probably no need to set these values).
Sponsored-by: On-Waves ehf
This sets the maximum MCS encoding used for EGPRS RLC data blocks
in either direction.
The following VTY command are added to node config-pcu:
- mcs max <1-9> set maximum for both, uplink and downlink
- mcs max <1-9> <1-9> set maximum for downlink and uplink (in that
order)
- no mcs max do not limit
Note that using a value of 4 or below for each direction implies
that a GMSK-only TBF may be assumed, which for instance would allow
the use of the GPRS MS class instead of the possibly more restrictive
EGPRS MS class.
Sponsored-by: On-Waves ehf
LListHead does basically the same like llist_pods, but more C++ish
and with type safety.
This commit turns the former list field of gprs_rlcmac_tbf into a
private field, provides accessors, moves the related code from
pcu_vty.c to pcu_vty_functions.cpp, and removes the llist_pods
type and related code.
Sponsored-by: On-Waves ehf
This commit removes the code that is no longer used due to the commit
"Use a single PDCH rcv_data_block method for GPRS and EGPRS".
Sponsored-by: On-Waves ehf
Currently GPRS is handled by the old code path while EGPRS already
uses the unified functions. The rcv_block_egprs is basically not
specific to EGPRS and just needs minor modifications to handle GPRS.
This commit turns gprs_rlcmac_pdch::rcv_block_egprs into a unified
rcv_data_block method and uses it for GPRS, too.
Note that the logging messages of the new parser are different.
Sponsored-by: On-Waves ehf
This commit renames rcv_data_block_acknowledged to
rcv_data_block_acknowledged_gprs to separate it from EGPRS data block
decoding.
Sponsored-by: On-Waves ehf
Currently the block size is mapped by a switch statement to strip
extra bits that are not used for RLC blocks. That information is
already available via the GprsCodingScheme class.
This commit moves the CS/MCS detection to the rcv_block message and
passes the cs object via rcv_block_gprs, where the length gets
adjusted, to gprs_rlcmac_pdch::rcv_data_block_acknowledged. There the
switch statement is removed.
Note that the TbfTest.err changes due to an additional log message.
Sponsored-by: On-Waves ehf
Add a global config flag to enable the use EDGE/EGPRS.
The following VTY commands are added to node config-pcu:
- egprs Enables EGPRS
- no egprs Disable EGPRS
Note that enabling EGPRS is experimental and will most likely break
packet transmission until a minimal required set of EGPRS
functionality is implemented.
Sponsored-by: On-Waves ehf
Add a global stat_item group for measurement values and a
corresponding macro to get and set the values.
Add a stat_item STAT_MS_PRESET to monitor the number of
MS objects in the storage.
Sponsored-by: On-Waves ehf
When a timeout has occured several times, the procedures handled by
poll_timeout are aborted. This happens when the number of repetitions
exceed N3105. Currently only the timeouts themselves are counted.
This commits adds counters that are incremented if a procedure has
really failed.
New counter:
- rlc.ass.failed: Count failing UL and DL assigments via PACCH
- rlc.ack.failed: Count failing DL Ack/Nack requests
Sponsored-by: On-Waves ehf
Currently all of these messages are discarded if they are assumend to
be caused by noise. But even in these cases, the FN and TN values
which are added by the DSP are valid. So these can be used to update
the current_frame value.
The osmo-bts sets the fBFILevel of a physical channel to -200dB if it
is used for PDTCH or PACCH which is the case for all PDCH. This way
a data_ind or ra_ind message is already send at least once per block
period (4 frames) per PDCH. These messages are passed to either
handle_ph_data_ind or handle_ph_ra_ind even if they contain garbage
data.
The ra_ind messages are sometimes sent a few frames earlier than
data_ind messages using the same frame.
This commit adds calls to update the current_frame value based on all
of these messages before they are discarded. The FN taken from ra_ind
are passed with an increased max_delay (5) to compensate for early
ra_ind messages.
Sponsored-by: On-Waves ehf
Currently a log entry is written if FN_data_ind - FN_time_ind <= -13.
This commit adds a counter 'rlc.late-block' that is incremented in
these cases.
Sponsored-by: On-Waves ehf
The FN of the data_ind taken from the DSP are monotonic, so latency
does not affect the detection of poll timeouts if these FN are used.
If the FN is larger than a poll_fn value, it can safely be assumed
that the poll response will not arrive later on.
Currently a max_delay of 60 frames is used, which has the drawback
that additional ~250ms will pass until a lost ACK is detected.
Using the data_ind's FN alone breaks the poll timeout detection if
there are no other MS sending data blocks.
This commit adds BTS::set_current_block_frame_number that is called
with the FN taken from data_ind messages. The max_delay is set to 0
which removes the additional delay, when this FN is used to detect
poll timeouts. So the average additional delay decreases with the
number of data_ind per time. The current_frame is updated unless it
seems to have been updated already (assumed if 0 < cur_fn - block_fn
< 500). Thus the time_ind has still priority to update the
current_frame value.
Sponsored-by: On-Waves ehf
This commit fixes several issues:
- Set MS class in request
- Set IMSI in establish_ul_tbf_two_phase
- Fake assigment acknowledgement in establish_ul_tbf_two_phase
- Fix TFI bit offset to 1 (was 2)
Sponsored-by: On-Waves ehf
Currently packets are only dropped if they have reached their maximum
life time. This leads to LLC queues being constantly filled under
load, increasing the latency up to the maximum life time. This kind
of bufferbloat hinders TCP's congestion avoidance algorithms. To keep
the queues short, the CoDel active queue management algorithm can be
used.
This commit changes to llc_dequeue method to apply the CoDel
algorithm to selectively drop LLC frames before they passed to the
TBF layer to be encoded in BSNs. This feature is currently disabled
by default.
The CoDel state is managed per MS since the LLC queues are also kept
in the MS objects.
Note that there is still some buffering in the TBF objects, in the
worst case (CS4) 3.5kByte + LLC-MTU octets are stored there. The
resulting additional packet delay is not (yet) taken into account for
CoDel.
Also note that configuration changes are applied to new MS objects
only.
The following VTY commands are added to the 'pcu' node:
- queue codel activates CoDel, the interval is selected by
the implementation
- queue codel interval <1-1000>
activates CoDel with a fixed interval given
in centiseconds (10ms-10s)
- no queue codel deactivates CoDel
Which interval value to use is still an open issue. For high speed
links (e.g. Ethernet), CoDel suggests 100ms. For slower links, the
expected RTT is recommended. The current implementation uses a
default value of 2000ms.
Measurements:
Note that the following measurements depend on several other factors,
most notably the interaction with the SGSN's flow control. They are
just examples to give an idea how CoDel might influence some
parameters.
The measurements have been done with a single E71, first with a
running ping only (Idle), then with an additional TCP download
of a 360k file (Busy). The CoDel interval was set to 1s.
- Idle :
ping ~400ms, avg queue delay 0ms, dropped 0
- Busy, No CoDel:
ping ~6s, avg queue delay 4-6s,
dropped 0, scheduled 948, duration 54s
- Busy, CoDel:
ping 500-1500ms, avg queue delay ~600ms,
dropped 77, scheduled 1040, duration 60s
More measurements with two MS downloading in parallel (two
independant measurements per case).
- Busy, No CoDel:
dropped 0, scheduled 1883, duration 121s
dropped 19, scheduled 2003, duration 133s
- Busy, CoDel:
dropped 22, scheduled 1926, duration 116s
dropped 22, scheduled 1955, duration 108s
Sponsored-by: On-Waves ehf
Currently there is no persistent state being used in
alloc_algorithm_dynamic. So algorithm B is even used in persistent
high usage scenarios. If there are many active TBFs, multislot
assigments are not fair, because MS of a "higher" multislot class get
higher troughputs. On the other hand, as long as all PDCH are busy no
bandwidth will be wasted even if all MS use algorithm A.
This commit modifies alloc_algorithm_dynamic to disable algorithm B
when that call fails. It then keeps it disabled until there is a
single PDCH which is idle (it is considered idle, if there is at most
one active DL TBF assigned to it).
Sponsored-by: On-Waves ehf
Currently the TBFs are registered in a TFI indexed array within the TRX
objects. TBFs can be searched globally by TFI and TRX number. This
conflicts with the use of the same TFI for different TBF on different
PDCH. This use case requires the specification of the PDCH as
additional search dimension.
This commit moves the TFI index TBF arrays into the PDCH objects. The
related methods are updated accordingly.
Ticket: #1793
Sponsored-by: On-Waves ehf
Currently the TFI and the TRX have to be determined before the actual TBF
allocation function is called, passing TFI and TRX number as
parameters. This does fit to TFI reuse for different slots, since
this were tightly coupled with the slot selection.
This commit just moves the TFI selection into the alloc_algorithm
functions. The tfi parameter is removed from the the TFI alloc
functions. The trx parameter is changed into use_trx to optionally
limit the trx selection (same semantics like in tfi_find_free).
Sponsored-by: On-Waves ehf
Currently a single bit set is used to maintain a set of used TFI
without distinguishing between uplink and downlink. Since the
namespaces of UL and DL TFI are separate, this implementation is
not correct.
This commit changes gprs_rlcmac_pdch to use a separate bit set for
each direction. It also replace the corresponding conditional fprintf
statement in check_tfi_usage (AllocTest.cpp) by an equivalent
OSMO_ASSERT.
Sponsored-by: On-Waves ehf
Currently is is rather expensive to get TFI and USF usage per PDCH,
because the TBFs need to be scanned to get that information.
This commit adds corresponding bit sets which get updated by the
attach_tbf/detach_tbf methods of the gprs_rlcmac_pdch class.
Sponsored-by: On-Waves ehf
This commits adds three poll timeout counters
- RLC Assign Timeout
- RLC Ack Timeout
- RLC Release Timeout
to help diagnosing to cause for these events. There seems to be an
increased rate of these when a PDCH is shared by multiple TBFs.
Sponsored-by: On-Waves ehf
In contrast to the slots currently used by existing TBFs, the
reserved slots refer to the time slots that can be used for newly
allocated TBFs without causing conflicts (given that the first common
TS does not change). They correspond to the potential use of the
PDCHs and can be used to achieve a more uniform slot allocation.
This commit adds bit set based methods to GprsMs and gprs_rlcmac_trx
and a counter to gprs_rlcmac_pdch. The current TRX will also be
stored in the MS object.
Sponsored-by: On-Waves ehf
Currently the PDCH object do not know anything about the TBFs using
them. To make the slot allocation load dependant, at least some
numbers are required.
This commit adds TBF counters (one per direction) and the related methods
attach_tbf, detach_tbf, and num_tbfs to gprs_rlcmac_pdch.
Sponsored-by: On-Waves ehf
Currently the code that creates the MS objects with tbf.cpp is
duplicated.
This commit moves the corresponding code into a new method. Since
there is no TLLI available there, the GprsMsStorage::create_ms method
has been refactored into two variants: one with TLLI/direction and
one without.
Sponsored-by: On-Waves ehf
Currently the old TBF (either uplink or downlink) is passed around at
TBF allocation mainly to get information about the MS. To implement
more complex allocation algorithms, the MS object itself will be
needed anyway.
This commit replaces the old_tbf arguments by MS object arguments.
Sponsored-by: On-Waves ehf
Harald Welte
Max
Philipp Maier