Revision history [back]

GPRS: PACKET SI STATUS Decoding Problem

Dear Sir/Madam

While decoding 3GPP GPRS RLC/MAC Uplink Control Message “PACKET_SI_STATUS”, it is seen that for MESSAGE_TYPE decoding text is showing as Invalid message type. (ideally it should be any valid System Information type).

Can you please help to check this decoding issue.?

According to 3GPP spec, 44.060, Table 11.2.17b.2: PACKET SI STATUS information element details, SI MESSAGE TYPE is as mentioned below.

SI_MESSAGE_TYPE (8 bit field) This field is the binary representation of the message type of the indicated SI message (see 3GPP TS 24.007 and 3GPP TS 44.018).

But from decoded output, it seems this IE value is taken from 44.060 not from 44.018.

Example:

** Wireshark decoder printing 0x03 as : .... 0000 0011 .... = MESSAGE_TYPE (DL): PACKET_MEASUREMENT_ORDER (3) But Ideally it should be 0 0 0 0 0 0 1 1 SYSTEM INFORMATION TYPE 2ter

RAW data of PDU is: 40 34 9b 19 63 6c 69 81 30 32 0e 47 18 fb 18 43 2b 2b 2b 2b 2b 2b 2b

Decoded output: SI_Message_List .... ...1 = SI_Message Exists: 1 SI_Message[0] 0001 1001 = MESSAGE_TYPE (DL): Invalid Message Type (25) 01.. .... = MESS_REC: 1 ..1. .... = SI_Message Exists: 1 SI_Message[0] ...0 0011 011. .... = MESSAGE_TYPE (DL): Invalid Message Type (27) ...0 1... = MESS_REC: 1 .... .1.. = SI_Message Exists: 1 SI_Message[0] .... ..00 0110 10.. = MESSAGE_TYPE (DL): Invalid Message Type (26) .... ..01 = MESS_REC: 1 1... .... = SI_Message Exists: 1 SI_Message[0] .000 0001 0... .... = MESSAGE_TYPE (DL): PACKET_DOWNLINK_ASSIGNMENT (2) .01. .... = MESS_REC: 1 ...1 .... = SI_Message Exists: 1 SI_Message[0] .... 0000 0011 .... = MESSAGE_TYPE (DL): PACKET_MEASUREMENT_ORDER (3) .... 00.. = MESS_REC: 0 .... ..1. = SI_Message Exists: 1 SI_Message[0] .... ...0 0000 111. = MESSAGE_TYPE (DL): PACKET_TIMESLOT_RECONFIGURE (7) .... ...0 0... .... = MESS_REC: 0 .1.. .... = SI_Message Exists: 1 SI_Message[0] ..00 0111 00.. .... = MESSAGE_TYPE (DL): Invalid Message Type (28) ..01 .... = MESS_REC: 1 .... 1... = SI_Message Exists: 1 SI_Message[0] .... .000 1111 1... = MESSAGE_TYPE (DL): Invalid Message Type (31) .... .01. = MESS_REC: 1 .... ...1 = SI_Message Exists: 1 SI_Message[0] 0001 1000 = MESSAGE_TYPE (DL): Invalid Message Type (24) 01.. .... = MESS_REC: 1 ...0 .... = Message List: 0 .... 0... = ADDITIONAL_MSG_TYPE: 0

GPRS: PACKET SI STATUS Decoding Problem

~~Dear Sir/Madam~~

Can you please help to check this decoding issue.?

According to 3GPP spec, 44.060, Table 11.2.17b.2: PACKET SI STATUS information element details, SI MESSAGE TYPE is as mentioned below.

SI_MESSAGE_TYPE (8 bit ~~field) This~~ field) This field is the binary representation of of the message type of the indicated SI SI message (see 3GPP TS 24.007 ~~and 3GPP~~ and 3GPP TS 44.018).

But from decoded output, it seems this IE value is taken from 44.060 not from 44.018.

Example:

Wireshark decoder printing 0x03 as : .... 0000  0011 .... = MESSAGE_TYPE (DL): PACKET_MEASUREMENT_ORDER (3)

But Ideally it should be 0 0 0 0 0 0 1 1 SYSTEM INFORMATION TYPE 2ter

RAW data of PDU is:

40 34 9b 19 63 6c 69 81 30 32 0e 47 18 fb 18 43 2b 2b 2b 2b 2b 2b 2b2b

Decoded ~~output:~~ output:

SI_Message_List
    .... ...1 = SI_Message Exists: 1
    SI_Message[0]
        0001 1001 = MESSAGE_TYPE (DL): Invalid Message Type (25)
        01.. .... = MESS_REC: 1
    ..1. .... = SI_Message Exists: 1
    SI_Message[0]
        ...0 0011  011. .... = MESSAGE_TYPE (DL): Invalid Message Type (27)
        ...0 1... = MESS_REC: 1
    .... .1.. = SI_Message Exists: 1
    SI_Message[0]
        .... ..00  0110 10.. = MESSAGE_TYPE (DL): Invalid Message Type (26)
        .... ..01 = MESS_REC: 1
    1... .... = SI_Message Exists: 1
    SI_Message[0]
        .000 0001  0... .... = MESSAGE_TYPE (DL): PACKET_DOWNLINK_ASSIGNMENT (2)
        .01. .... = MESS_REC: 1
    ...1 .... = SI_Message Exists: 1
    SI_Message[0]
        .... 0000  0011 .... = MESSAGE_TYPE (DL): PACKET_MEASUREMENT_ORDER (3)
        .... 00.. = MESS_REC: 0
    .... ..1. = SI_Message Exists: 1
    SI_Message[0]
        .... ...0  0000 111. = MESSAGE_TYPE (DL): PACKET_TIMESLOT_RECONFIGURE (7)
        .... ...0  0... .... = MESS_REC: 0
    .1.. .... = SI_Message Exists: 1
    SI_Message[0]
        ..00 0111  00.. .... = MESSAGE_TYPE (DL): Invalid Message Type (28)
        ..01 .... = MESS_REC: 1
    .... 1... = SI_Message Exists: 1
    SI_Message[0]
        .... .000  1111 1... = MESSAGE_TYPE (DL): Invalid Message Type (31)
        .... .01. = MESS_REC: 1
    .... ...1 = SI_Message Exists: 1
    SI_Message[0]
        0001 1000 = MESSAGE_TYPE (DL): Invalid Message Type (24)
        01.. .... = MESS_REC: 1
    ...0 .... = Message List: 0
    .... 0... = ADDITIONAL_MSG_TYPE: 00