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Bug #6330
openIncorrect handling of V.120 data calls
Status:
New
Priority:
Normal
Assignee:
-
Category:
Call Control
Target version:
-
Start date:
01/18/2024
Due date:
% Done:
0%
Resolution:
Spec Reference:
Description
Current osmo-msc (8236184ef05e5b10505bbb3189357d2050bbdc5d) fails to connect a V.120 data call, see the attached PCAP.
How to reproduce:
- find phone(s)/modem(s) supporting V.120 data calls
- the result of
AT+CBST=?
should contain one of V.120 rates: 39, 43, 47, 48 - most Sony Ericsson phones/modems can do V.120:
+CBST: (0,7,12,14-17,39,43,47-51,71,75,79-84),(0,4),(1)
- the result of
- configure phone(s)/modem(s) to use V.120, for example:
AT+CBST=39,0,1
for 9600 bps - initiate a data call, for example:
ATD15843
In my case (using SE K800), the call is aborted due to Assignment Failure, because osmo-msc sends weird Assignment Command:
GSM A-I/F BSSMAP - Assignment Request Message Type Assignment Request Channel Type - (Data) Element ID: 0x0b Length: 3 0000 .... = Spare bit(s): 0x00 .... 0010 = Speech/Data Indicator: Data (2) .000 1010 = Channel rate and type: Full or Half rate TCH channel, Full rate preferred, changes allowed also after first channel allocation as a result of the request (10) 0... .... = Extension: Last Octet .0.. .... = Service: Transparent ..01 0010 = Rate: 2.4kbit/s ...
2.4kbit/s
/ Transparent
is definitely not what the calling phone requested, it should be 9.6kbit/s
/ Non-transparent
.
Below is how the Bearer Capability looks like for AT+CBST=39,0,1
:
Bearer Capability 1 - (Full rate support only MS) Element ID: 0x04 Length: 12 Octet 3 1... .... = Extension: No Extension .01. .... = Radio channel requirement: Full rate support only MS ...0 .... = Coding standard: GSM standardized coding .... 0... = Transfer mode: circuit .... .001 = Information transfer capability: Unrestricted digital information (0x1) Octet 4 1... .... = Extension: No Extension .1.. .... = Compression: Allowed ..00 .... = Structure: Service data unit integrity (0) .... 1... = Duplex mode: Full .... .0.. = Configuration: Point-to-point .... ..0. = NIRR: No meaning is associated with this value .... ...0 = Establishment: Demand Octet 5 0... .... = Extension: Extended .00. .... = Access Identity: Octet identifier (0) ...1 1... = Rate Adaption: Other rate adaption (see octet 5a) (3) .... .001 = Signalling Access Protocol: According to ITU-T Rec. Q.920 and ITU-T Rec. Q.930 (1) Octet 5a 0... .... = Extension: Extended .00. .... = Other ITC: Restricted digital information (0) ...0 0... = Other Rate Adaption: According to ITU-T Rec. V.120 (0) .... .000 = Spare bit(s): 0 Octet 5b 1... .... = Extension: No Extension .1.. .... = Rate Adaption Header: Included ..1. .... = Multiple frame establishment support in data link: Supported ...1 .... = Mode of operation: Protocol sensitive .... 0... = Logical link identifier negotiation: Default, LLI=256 only .... .0.. = Assignor/Assignee: Message originator is default assignee .... ..0. = In band/Out of band negotiation: Negotiation is done in-band using logical link zero .... ...0 = Spare bit(s): 0 Octet 6 0... .... = Extension: Extended .01. .... = Layer 1 Identity: Octet identifier ...0 000. = User information layer 1 protocol: Default layer 1 protocol .... ...1 = Synchronous/asynchronous: Asynchronous Octet 6a 0... .... = Extension: Extended .0.. .... = Number of Stop Bits: 1 ..0. .... = Negotiation: In-band negotiation not possible ...1 .... = Number of data bits excluding parity bit if present: 8 .... 0101 = User rate: 9.6 kbit/s (according to ITU-T Rec. X.1 and ITU-T Rec. V.110) Octet 6b 0... .... = Extension: Extended .11. .... = V.110/X.30 rate adaptation Intermediate rate: 16 kbit/s (3) ...0 .... = Network independent clock (NIC) on transmission (Tx): does not require to send data with network independent clock .... 0... = Network independent clock (NIC) on reception (Rx): cannot accept data with network independent clock .... .011 = Parity information: None (3) Octet 6c 0... .... = Extension: Extended .01. .... = Connection element: Non transparent (RLP) (1) ...0 0000 = Modem type: None Octet 6d 0... .... = Extension: Extended .00. .... = Other modem type: No other modem type specified in this field (0) ...0 0001 = Fixed network user rate: 9.6 kbit/s (according to ITU-T Rec. X.1 and ITU-T Rec. V.110) Octet 6e 0... .... = Extension: Extended .1.. .... = Acceptable channel codings (TCH/F14.4): Acceptable ..0. .... = Acceptable channel codings (Spare): False ...1 .... = Acceptable channel codings (TCH/F9.6): Acceptable .... 0... = Acceptable channel codings (TCH/F4.8): Not Acceptable .... .001 = Maximum number of traffic channels: 1 TCH Octet 6f 1... .... = Extension: No Extension .000 .... = UIMI, User initiated modification indication: not allowed/required/applicable (0) .... 0001 = Wanted air interface user rate: 9.6 kbit/s (1)
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Related issues
Updated by fixeria 3 months ago
- Related to Feature #6344: New TS 24.008 Bearer Capability codec API added
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