Ccch scan » History » Version 1
Anonymous, 02/19/2016 10:49 PM
Copied from /trac/wiki/layer23 version 8; this reflects the name change in the current code.
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2 | = ccch_scan = |
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3 | |||
4 | The ''ccch_scan'' program (formerly layer23) is the playground we use for developing the GSM Protocol layers 2 and 3 (GSM TS 04.05, 04.06, 04.08) |
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5 | |||
6 | Using the ccch_scan program, you can: |
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7 | * Connect to /tmp/osmocom_l2 socket created by [wiki:osmocon] to exchange data from [wiki:L1A_L23_Interface]. |
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8 | * Receive GSM Layer1 frames. |
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9 | * Dump received GSM Layer1 frames and print some analysis. |
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10 | * Send the Layer1 frames as [wiki:GSMTAP] packets to wireshark (see [wiki:WiresharkIntegration]) |
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11 | * forward the Layer1 frames to the Layer2 / LAPDm implementation inside ccch_scan |
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12 | * forward them from Layer2 into Layer3 code inside ccch_scan. |
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13 | * receive outgoing frames from Layer3 |
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14 | * process them through layer2 |
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15 | * send them as uplink frames to [wiki:GSMTAP] |
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16 | * send them to the Layer1 on the phone |
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17 | |||
18 | The ''ccch_scan'' program is used in combination with the [wiki:layer1.bin] firmware. |
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19 | |||
20 | === Usage === |
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21 | {{{ |
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22 | ./ccch_scan -a 871 -i 127.0.0.1 |
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23 | }}} |
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24 | |||
25 | where {{{-a 871}}} indicates the GSM ARFCN to which layer1 shall tune, and {{{-i 127.0.0.1}}} indicates the IP address |
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26 | to which the [wiki:GSMTAP] messages are to be sent. |
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27 | |||
28 | This will connect to the [wiki:osmocon] application and will receive GSM Layer1 frames. |
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29 | The receiving is done in the src/main.c and the frames will be passed to src/l1ctl.c, |
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30 | from there into src/lapdm.c and finally into src/layer3.c |
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31 | |||
32 | The output of the ccch_scan application is currently looking like this: |
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33 | {{{ |
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34 | Found CCCH burst(s): TDMA: (0003/08/39) tc:3 49 06 1b 3b 80 62 f2 20 01 3a c8 07 0a 15 65 04 b9 00 00 80 00 02 1b si: 0x1b |
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35 | SI3 on wrong TC |
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36 | Found sync burst: SNR: 16384 TDMA: (0003/15/46) bsic: 49 |
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37 | Found sync burst: SNR: 16384 TDMA: (0003/25/05) bsic: 49 |
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38 | Found sync burst: SNR: 16384 TDMA: (0003/09/15) bsic: 49 |
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39 | Found sync burst: SNR: 16384 TDMA: (0003/19/25) bsic: 49 |
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40 | Found CCCH burst(s): TDMA: (0003/07/39) tc:4 31 06 1c 62 f2 20 01 3a 65 04 b9 00 00 80 00 53 2b 2b 2b 2b 2b 2b 2b si: 0x1c |
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41 | SI4 on wrong TC |
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42 | Found sync burst: SNR: 16384 TDMA: (0003/14/46) bsic: 49 |
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43 | Found sync burst: SNR: 16384 TDMA: (0003/24/05) bsic: 49 |
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44 | Found sync burst: SNR: 16384 TDMA: (0003/08/15) bsic: 49 |
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45 | Found sync burst: SNR: 16384 TDMA: (0003/18/25) bsic: 49 |
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46 | Found CCCH burst(s): TDMA: (0003/06/39) tc:5 01 06 00 b0 00 58 47 eb 4a 92 53 40 62 84 eb 2b 2b 2b 2b 2b 2b 2b 2b si: 0x0 |
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47 | SI13 on wrong TC |
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48 | }}} |