Hello,
I found the BSSAP dissector is very good. Each Element Identifier has its handle [+] to expand its subtree. This way, I can see which Element Identifiers are present in the message. It is very detailed.
I would like to report a bug. In the text below, Octet 6 and Octet 7 are decoded as if they had value 0x81. But in fact, octet 6 is 0x21 and octet 7 is 0x15. The value 0x81 is actually the value of octet 5, which is being repeated for octet 6 and 7, thus making the decoding incorrect (Extraneous Data).
Bearer Capability 1 - (3.1 kHz audio, ex PLMN)
Element ID: 4
Length: 7
1... .... : Extension: not extended
.01. .... : Radio channel requirement: Full rate support only MS
...0 .... : Coding standard: GSM standardized coding
.... 0... : Transfer mode: circuit
.... .010 : Information transfer capability: 3.1 kHz audio, ex PLMN
Octet 4
1... .... : Extension: not extended
.0.. .... : Compression: data
compression not allowed
..11 .... : Structure: Unstructured
.... 1... : Duplex mode: Full
.... .0.. : Configuration: Point-to-point
.... ..0. : NIRR: No meaning is associated with this value
.... ...0 : Establishment: Demand
Octet 5
1... .... : Extension: not extended
.00. .... : Access Identity: Octet identifier
...0 0... : Rate Adaption:
No rate adaption
.... .001 : Signalling Access Protocol: I.440/450
---> Octet 6
1... .... : Extension: not extended
.00. .... : Layer 1 Identity: Reserved
...0 000. : User information layer 1 protocol: Default layer 1 protocol
.... ...1 : Synchronous/asynchronous:
Asynchronous
---> Octet 7
1... .... : Extension: not extended
.00. .... : Layer 2 Identity: Reserved
...0 0001 : User information layer 2 protocol: Reserved
Extraneous Data
0000 83 01 01 01 02 02 02 00 06 56 34 12 00 01 1a 01 .........V4.....
0010 00 17 53 45 04 07 a2 b8 81 21 15 63 86 5e 07 81 ..SE.....!.c.^..
^ ^ ^
It looks like in line 4663 (octet 6) and 5218 (octet 7) of file packet-gsm_a.c , missing the code:
oct = tvb_get_guint8(tvb, curr_offset);
Please find attached the trace, which is of ANSI MTP3.
Thanks and Regards,
Soi Hon Lo
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Attachment:
GSM-BSSAP-BC.cap
Description: GSM-BSSAP-BC.cap
