Sierra Wireless MC7354 remains in Registered - RRC Idle indefinitely on LTE mode

Diego López dlopezm at teltronic.es
Fri Apr 29 15:35:35 UTC 2016


Hi Dan,

Thank you for the information, it helped a lot for approaching the problem.

I've been making more tests but sending traffic doesn't wake up the modem.

I'm going to continue working on it because I suspect that my MMC has 
EMM states are wrong implemented (I see my UE deregistered on my MME 
when this happens) .

UE should be transition to ECM connected when:

* There is new traffic
* On a Tracking Area Update (TAU) request.

I just want to confirm, Modem Manager has nothing to do with wake up a 
modem that remains in RRC-Idle indefinitely?

Diego

> On Tue, 2016-04-26 at 17:27 +0200, Diego López wrote:
>> Hi,
>>
>> I'm still working with Sierra Wireless MC7354 modem, this time with
>> only
>> LTE connection. My tests are made by using a signal attenuator with
>> only
>> one cell.
>>
>> Bringing the modem al low signal levels I discovered two different
>> cases:
>>
>> * Case 1 - High signal - low signal - high signal (slowly) OK:
>>
>> Modem state machine transist correctly
>> (connected->disconnecting->enabled->searching->registered-
>>> connecting->connected)
>> * Case 2 - High signal - low signal - high signal (slowly) FAILURE:
>>
>> This test case attempts to simulate something similar to the
>> entrance/exit of a tunnel.
>>
>> ModemManager state machine doesn't transist, it remains connected
>> and
>> the bearer doesn't disconnect. Reset MM service doesn't recover
>> connection, only reset modem works.
> MM follows the modem's idea of whether the bearer is disconnected or
> not.  I'll bet in the first case, you got status indications that the
> bearer was detached, but in the second case you didn't because the
> firmware doesn't think the bearer is destroyed.
>
>> But querying Modem by AT!GSTATUS? command, we can see that it is on
>> RRC
>> Idle indefinitely:
> EMM-Registered & RRC-Idle means network resources are allocated for the
> bearer, but not all radio resources are allocated.  If you try to send
> traffic does that wake up the modem?  Looking at some documentation it
> seems in the RRC Idle state the modem is waiting for something to
> happen before it will ask the network to re-allocate downlink resources
> for actual communication.  Supposedly the uplink resources are still
> allocated and available to the modem (hence why it is still Registered
> & Attached), but the modem doesn't think it has anything to do.
>
> If IP data doesn't work try sending an SMS; does that wake it up?  If
> not, do you see any indications/status from the modem via QMI that the
> bearer has disconnected?  They'd come from the NAS or WDS services.
>
> Dan
>
>> !GSTATUS:
>> Current Time:  1518        Temperature: 40
>> Bootup Time:   0        Mode:        ONLINE
>> System mode:   LTE            PS state:    Attached
>> LTE band:      B13            LTE bw:      5 MHz
>> LTE Rx chan:   5230        LTE Tx chan: 23230
>> EMM state:     Registered         No Cell
>> RRC state:     RRC Idle
>> IMS reg state: No Srv
>>
>> RSSI (dBm):    -87        Tx Power:    0
>> RSRP (dBm):    -106        TAC:         0001 (1)
>> RSRQ (dB):     -6        Cell ID:     00000100 (256)
>> SINR (dB):     19.2
>>
>> MM log between RRC connected and RRC Idle states:
>>
>> ModemManager[11185]: [/dev/cdc-wdm0] Received message (translated)...
>>   >>>>>> QMUX:
>>   >>>>>>   length  = 31
>>   >>>>>>   flags   = 0x80
>>   >>>>>>   service = "nas"
>>   >>>>>>   client  = 2
>>   >>>>>> QMI:
>>   >>>>>>   flags       = "response"
>>   >>>>>>   transaction = 14
>>   >>>>>>   tlv_length  = 19
>>   >>>>>>   message     = "Get Signal Strength" (0x0020)
>>   >>>>>> TLV:
>>   >>>>>>   type       = "Result" (0x02)
>>   >>>>>>   length     = 4
>>   >>>>>>   value      = 00:00:00:00
>>   >>>>>>   translated = SUCCESS
>>   >>>>>> TLV:
>>   >>>>>>   type       = "Signal Strength" (0x01)
>>   >>>>>>   length     = 2
>>   >>>>>>   value      = 9E:08
>>   >>>>>>   translated = [ strength = '-98' radio_interface = 'lte' ]
>>   >>>>>> TLV:
>>   >>>>>>   type       = "Strength List" (0x10)
>>   >>>>>>   length     = 4
>>   >>>>>>   value      = 01:00:83:02
>>   >>>>>>   translated = { [0] = '[ strength = '-125' radio_interface
>> =
>> 'cdma-1xevdo' ] '}
>> ModemManager[11185]: <debug> [1461671245.821746]
>> [mm-broadband-modem-qmi.c:2841]
>> signal_strength_get_quality_and_access_tech(): Signal strength
>> (lte):
>> -98 dBm
>> ModemManager[11185]: <debug> [1461671245.821772]
>> [mm-broadband-modem-qmi.c:2860]
>> signal_strength_get_quality_and_access_tech(): Signal strength
>> (cdma-1xevdo): -125 dBm
>> ModemManager[11185]: <debug> [1461671245.821794]
>> [mm-broadband-modem-qmi.c:2874]
>> signal_strength_get_quality_and_access_tech(): Signal strength: -98
>> dBm
>> --> 25%
>> ModemManager[11185]: <debug> [1461671245.821866] [mm-iface-
>> modem.c:1204]
>> update_signal_quality(): Modem
>> /org/freedesktop/ModemManager1/Modem/0:
>> signal quality updated (25)
>> ModemManager[11185]: [/dev/cdc-wdm0] Received message...
>>   >>>>>> RAW:
>>   >>>>>>   length = 42
>>   >>>>>>   data   =
>> 01:29:00:80:01:09:02:05:00:24:00:1D:00:02:04:00:00:00:00:00:1A:08:00:
>> D8:09:00:00:00:00:00:00:19:08:00:E1:18:00:00:00:00:00:00
>> ModemManager[11185]: [/dev/cdc-wdm0] Received message (translated)...
>>   >>>>>> QMUX:
>>   >>>>>>   length  = 41
>>   >>>>>>   flags   = 0x80
>>   >>>>>>   service = "wds"
>>   >>>>>>   client  = 9
>>   >>>>>> QMI:
>>   >>>>>>   flags       = "response"
>>   >>>>>>   transaction = 5
>>   >>>>>>   tlv_length  = 29
>>   >>>>>>   message     = "Get Packet Statistics" (0x0024)
>>   >>>>>> TLV:
>>   >>>>>>   type       = "Result" (0x02)
>>   >>>>>>   length     = 4
>>   >>>>>>   value      = 00:00:00:00
>>   >>>>>>   translated = SUCCESS
>>   >>>>>> TLV:
>>   >>>>>>   type       = "Rx Bytes Ok" (0x1a)
>>   >>>>>>   length     = 8
>>   >>>>>>   value      = D8:09:00:00:00:00:00:00
>>   >>>>>>   translated = 2520
>>   >>>>>> TLV:
>>   >>>>>>   type       = "Tx Bytes Ok" (0x19)
>>   >>>>>>   length     = 8
>>   >>>>>>   value      = E1:18:00:00:00:00:00:00
>>   >>>>>>   translated = 6369
>> ModemManager[11185]: <debug> [1461671250.815327] [mm-port-
>> serial.c:1288]
>> mm_port_serial_open(): (ttyUSB2) device open count is 2 (open)
>> ModemManager[11185]: <debug> [1461671250.815749]
>> [mm-port-serial-at.c:459] debug_log(): (ttyUSB2): -->
>> 'AT!GSTATUS?<CR>'
>> ModemManager[11185]: <debug> [1461671250.932135]
>> [mm-port-serial-at.c:459] debug_log(): (ttyUSB2): <--
>> '<CR><LF>!GSTATUS:
>> <CR><LF>Current Time: 1506\9\9Temperature: 40<CR><LF>Bootup Time:
>> 0\9\9Mode:        ONLINE         <CR><LF>System mode:
>> LTE        \9PS
>> state:    Attached     <CR><LF>LTE band:      B13    \9\9LTE
>> bw:      5
>> MHz   <CR><LF>LTE Rx chan:   5230\9\9LTE Tx chan: 23230<CR><LF>EMM
>> state:     Registered     \9Normal Service <CR><LF>RRC
>> state:     RRC
>> Connected  <CR><LF>IMS reg state: No Srv \9\9<CR><LF><CR><LF>RSSI
>> (dBm):    -98\9\9Tx Power:    0<CR><LF>RSRP (dBm):    -126\9\9TAC:
>> 0001
>> (1)<CR><LF>RSRQ (dB):     -9\9\9Cell ID: 00000100 (256)<CR><LF>SINR
>> (dB): 0.2<CR><LF><CR><LF><CR><LF>OK<CR><LF>'
>> ModemManager[11185]: <debug> [1461671250.932764] [mm-port-
>> serial.c:1345]
>> _close_internal(): (ttyUSB2) device open count is 1 (close)
>> ModemManager[11185]: <debug> [1461671256.942383] [mm-port-
>> serial.c:1288]
>> mm_port_serial_open(): (ttyUSB2) device open count is 2 (open)
>> ModemManager[11185]: <debug> [1461671256.943353]
>> [mm-port-serial-at.c:459] debug_log(): (ttyUSB2): -->
>> 'AT!GSTATUS?<CR>'
>> ModemManager[11185]: <debug> [1461671257.061151]
>> [mm-port-serial-at.c:459] debug_log(): (ttyUSB2): <--
>> '<CR><LF>!GSTATUS:
>> <CR><LF>Current Time: 1512\9\9Temperature: 40<CR><LF>Bootup Time:
>> 0\9\9Mode:        ONLINE         <CR><LF>System mode:
>> LTE        \9PS
>> state:    Attached     <CR><LF>LTE band:      B13    \9\9LTE
>> bw:      5
>> MHz   <CR><LF>LTE Rx chan:   5230\9\9LTE Tx chan: 23230<CR><LF>EMM
>> state:     Registered     \9Normal Service <CR><LF>RRC
>> state:     RRC
>> Connected  <CR><LF>IMS reg state: No Srv \9\9<CR><LF><CR><LF>RSSI
>> (dBm):    -98\9\9Tx Power:    0<CR><LF>RSRP (dBm):    -122\9\9TAC:
>> 0001
>> (1)<CR><LF>RSRQ (dB):     -14\9\9Cell ID: 00000100 (256)<CR><LF>SINR
>> (dB): 2.6<CR><LF><CR><LF><CR><LF>OK<CR><LF>'
>> ModemManager[11185]: <debug> [1461671257.061991] [mm-port-
>> serial.c:1345]
>> _close_internal(): (ttyUSB2) device open count is 1 (close)
>> ModemManager[11185]: [/dev/cdc-wdm0] Received message...
>>   >>>>>> RAW:
>>   >>>>>>   length = 50
>>   >>>>>>   data   =
>> 01:31:00:80:03:02:04:00:00:24:00:25:00:29:05:00:A8:01:A8:01:01:12:0C:
>> 00:A8:01:A8:01:07:34:32:34:2D:34:32:34:11:02:00:01:0B:01:06:00:01:01:
>> 01:02:01:08
>> ModemManager[11185]: [/dev/cdc-wdm0] Received message (translated)...
>>   >>>>>> QMUX:
>>   >>>>>>   length  = 49
>>   >>>>>>   flags   = 0x80
>>   >>>>>>   service = "nas"
>>   >>>>>>   client  = 2
>>   >>>>>> QMI:
>>   >>>>>>   flags       = "indication"
>>   >>>>>>   transaction = 0
>>   >>>>>>   tlv_length  = 37
>>   >>>>>>   message     = "Serving System" (0x0024)
>>   >>>>>> TLV:
>>   >>>>>>   type       = "MNC PCS Digit Include Status" (0x29)
>>   >>>>>>   length     = 5
>>   >>>>>>   value      = A8:01:A8:01:01
>>   >>>>>>   translated = [ mcc = '424' mnc = '424' includes_pcs_digit
>> =
>> 'yes' ]
>>   >>>>>> TLV:
>>   >>>>>>   type       = "Current PLMN" (0x12)
>>   >>>>>>   length     = 12
>>   >>>>>>   value      = A8:01:A8:01:07:34:32:34:2D:34:32:34
>>   >>>>>>   translated = [ mcc = '424' mnc = '424' description = '424-
>> 424' ]
>>   >>>>>> TLV:
>>   >>>>>>   type       = "Data Service Capability" (0x11)
>>   >>>>>>   length     = 2
>>   >>>>>>   value      = 01:0B
>>   >>>>>>   translated = { [0] = 'lte '}
>>   >>>>>> TLV:
>>   >>>>>>   type       = "Serving System" (0x01)
>>   >>>>>>   length     = 6
>>   >>>>>>   value      = 01:01:01:02:01:08
>>   >>>>>>   translated = [ registration_state = 'registered'
>> cs_attach_state = 'attached' ps_attach_state = 'attached'
>> selected_network = '3gpp' radio_interfaces = '{ [0] = 'lte '}' ]
>> ModemManager[11185]: <debug> [1461671260.670856]
>> [mm-broadband-modem-qmi.c:4607]
>> common_process_serving_system_3gpp():
>> Processing 3GPP info...
>> ModemManager[11185]: <info>  [1461671260.671082]
>> [mm-iface-modem-3gpp.c:1171] update_registration_state(): Modem
>> /org/freedesktop/ModemManager1/Modem/0: 3GPP Registration state
>> changed
>> (roaming -> registering)
>> ModemManager[11185]: <info>  [1461671260.671336]
>> [mm-iface-modem-3gpp.c:1096]
>> update_registration_reload_current_registration_info_ready(): Modem
>> /org/freedesktop/ModemManager1/Modem/0: 3GPP Registration state
>> changed
>> (registering -> home)
>> ModemManager[11185]: <debug> [1461671263.072413] [mm-port-
>> serial.c:1288]
>> mm_port_serial_open(): (ttyUSB2) device open count is 2 (open)
>> ModemManager[11185]: <debug> [1461671263.072658]
>> [mm-port-serial-at.c:459] debug_log(): (ttyUSB2): -->
>> 'AT!GSTATUS?<CR>'
>> ModemManager[11185]: <debug> [1461671263.092805]
>> [mm-port-serial-at.c:459] debug_log(): (ttyUSB2): <--
>> '<CR><LF>!GSTATUS:
>> <CR><LF>Current Time: 1518\9\9Temperature: 40<CR><LF>Bootup Time:
>> 0\9\9Mode:        ONLINE         <CR><LF>System mode:
>> LTE        \9PS
>> state:    Attached     <CR><LF>LTE band:      B13    \9\9LTE
>> bw:      5
>> MHz   <CR><LF>LTE Rx chan:   5230\9\9LTE Tx chan: 23230<CR><LF>EMM
>> state:     Registered     \9No Cell        <CR><LF>RRC
>> state:     RRC
>> Idle       <CR><LF>IMS reg state: No Srv \9\9<CR><LF><CR><LF>RSSI
>> (dBm):    -87\9\9Tx Power:    0<CR><LF>RSRP (dBm):    -106\9\9TAC:
>> 0001
>> (1)<CR><LF>RSRQ (dB):     -6\9\9Cell ID: 00000100 (256)<CR><LF>SINR
>> (dB): 19.2<CR><LF><CR><LF><CR><LF>OK<CR><LF>'
>> ModemManager[11185]: <debug> [1461671263.093076] [mm-port-
>> serial.c:1345]
>> _close_internal(): (ttyUSB2) device open count is 1 (close)
>> ModemManager[11185]: [/dev/cdc-wdm0] Received message...
>>   >>>>>> RAW:
>>   >>>>>>   length = 18
>>   >>>>>>   data   =
>> 01:11:00:80:03:02:04:00:00:02:00:05:00:10:02:00:B5:08
>> ModemManager[11185]: [/dev/cdc-wdm0] Received message (translated)...
>>   >>>>>> QMUX:
>>   >>>>>>   length  = 17
>>   >>>>>>   flags   = 0x80
>>   >>>>>>   service = "nas"
>>   >>>>>>   client  = 2
>>   >>>>>> QMI:
>>   >>>>>>   flags       = "indication"
>>   >>>>>>   transaction = 0
>>   >>>>>>   tlv_length  = 5
>>   >>>>>>   message     = "Event Report" (0x0002)
>>   >>>>>> TLV:
>>   >>>>>>   type       = "Signal Strength" (0x10)
>>   >>>>>>   length     = 2
>>   >>>>>>   value      = B5:08
>>   >>>>>>   translated = [ strength = '-75' radio_interface = 'lte' ]
>> ModemManager[11185]: <debug> [1461671266.334031]
>> [mm-broadband-modem-qmi.c:7030] event_report_indication_cb(): Signal
>> strength indication (lte): -75 dBm --> 62%
>> ModemManager[11185]: <debug> [1461671266.334135] [mm-iface-
>> modem.c:1204]
>> update_signal_quality(): Modem
>> /org/freedesktop/ModemManager1/Modem/0:
>> signal quality updated (62)
>>
>> Diego López
>> Teltronic
>> _______________________________________________
>> ModemManager-devel mailing list
>> ModemManager-devel at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/modemmanager-devel



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