Location Update Message Decoding


Location Update Flow :

***********************************************************************
 Mobile Station                                                                 MSC
*************************************************************
----------------------Initial_UE(CM_SERVICE_REQ)  -->|
---------------------------Dir_Trnx(AUTH_REQ)         <--|
---------------------------Dir_Trnx(AUTH_RSP)          -->|
-----------------------------Cipher Mode Command     <--|
-----------------------------Cipher Mode Complete      -->|
---------------------Dir_Trnx(TMSI_RELOC_CMD)   <--|
----------------------Dir_Trnx(LOCUPD_ACCEPT)    <--|
------------------------TMSI_RELOC_COMP            <--|
--------------------------------Clear Cmd                     <--|
--------------------------------Clear Comp                   -->|

***********************************************************************


CM Service Request/Location Update Request

*******************************************************************
00 21 57 05 08 00 13 f0 79 00 01 00 01 17 12 05 08 70 13 f0 79 ff fe 30 08 89 88 88 12 45 12 00 00 21 01 00

00                                                        Message discriminator
21                                                        length
57                                                        message type BSSMAP
05 08 00 13 f0 79 00 01 00 01            ID, length and value of Cell Identifier
                                                            Cell Identifier
05        IE
08        Length
00        Cell Identifier discriminator
13 F0   MCC1-> 3, MCC2 ->1, MCC3-> 0 MCC: 310
79        MNC1->9, MNC2->7                         MNC: 97
00 01   LAC: 1.Represent LAC in hex and put in two bytes
00 01   CI: 1   represents CI in hex and put in two bytes

17 12                                                   message type and length of layer3
05                                                        TI flag, value and protocol discriminator  (Mobility management).
08                                                        message type of LU
70                                                        Chiperkey sequence No.
13 f0 79 ff fe                                       Location Area Identification
30 08 89 88 88 12 45 12 00 00           IMSI
21 01 00                                              Mobility Management.


Authentication Request

********************************************
01 00 13 05 12 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

01                                                        Message Discriminator
00                                                        Ctrl Channel not further specified (00), spare (000), sapi (000)
13                                                        Length (19)
05                                                        Mobility Management
12                                                        Message Type DTAP
01/02                                                  Possible value for ciphering key sequence number
00 00 00 00 00 00 00 00 00                Authentication RAND
00 00 00 00 00 00 00                                     


Authentication Response

**********************************************
01 00 06 05 54 00 00 00 00

01                                                        Message Discriminator
00                                                        Ctrl Channel not further specified (00), spare (000), sapi (000)
06                                                        Length (06)
05                                                        Mobility Management
54                                                        Message Type
00 00 00 00                                         Authentication SRES


Class Mark Request

*************************************************
00 01 58

00                                                        Message Discriminator
01                                                        Length (1)
58                                                        Message Type


Class Mark Update

***********************************
00 0b 54 12 03 30 59 81 13 02 60 14 00

00                                                        Message Discriminator
0b                                                        Length (10)
54                                                        Message Type
12                                                        Classmark Information Type 2
03                                                        Length (03)
30 59 81                                              Class Mark
13                                                        Classmark Information Type 3
02                                                        Length (02)
60 14                                                   Class Mark
00                                                        end of Optional parameters.


Cipher Mode Command

********************************************
00 0e 53 0a 09 07 00 00 00 00 00 00 00 00 23 01

00                                                        Message Discriminator
0e                                                        Length (15)
53                                                        Message Type
0a                                                        Encryption Information
09                                                        Length (09)
07 00 00 00 00 00 00 00 00                Encryption Information
23                                                        Cipher Response Mode (Phase 2)
01                                                        Spare/ IMEISV must be Included By The Mobile Station  

Cipher Mode Complete


00 10 55 20 0b 17 09 33 05 70 87 70 35 17 01 f9 2c 01

00                                                        Message Discriminator
10                                                        Length (17)
55                                                        Message Type
20                                                        Layer 3 Message contents (Phase 2)
0b                                                        Length (11)
17 09 33 05 70 87 70 35 17 01 f9       Contents
2c                                                        Chosen Encryption Algorithm
01                                                        No Encryption used


Location Update Accept

********************************************
01 00 0e 05 02 13 f0 69 00 03 17 05 f4 0f 2f 20 04 00 02 01

01                                                        Message Discriminator
00                                                        Ctrl Channel not further specified (00), spare (000), sapi (000)
0e                                                        Length (15)
05                                                        Mobility Management
02                                                        Message Type
13 F0                                                   MCC1-> 3, MCC2 ->1, MCC3-> 0 MCC: 310
69                                                        MNC1->9, MNC2->6                         MNC: 96
00 03                                                   LAC
17                                                        Mobility Identity
05                                                        Parameter Length
f4                                                         ST 0/Even Number of Address Signals / TMSI
0f 2f 20 04 00 02 01                            Identity Digits

Clear Command

******************************
00 04 20 04 01 09

00                                                        Message Discriminator
04                                                        Length (04)
20                                                        Message Type
04                                                        Cause
01                                                        Length
09                                                        Extension bit (last octet) / Call Control Normal Event


Clear Complete

*****************************
00 01 21

00                                                        Message Discriminator
01                                                        Length (1)
21                                                        Message Type


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