Attach Type
The Attach Type indicates the purpose of the attach and as in most of other procedure, the attach type is also determined by a kind of mutual agreement between UE and Network. It means that UE indicates the attatch type I want to get and Network finaly determines available attach type and informs it to UE as in following procedure.
There are three different types of attach as listed below.
- EPS attach : indicate the attach for EPS services only)
- Combined EPS/IMSI attach : indicate the attach for both EPS and non-EPS services
- EPS emergency attach : indicate the attach for emergency bearer services
|
Direction |
Message |
|
UE --> NW |
RRC : RRC Connection Setup Complete + NAS : Attach Request + ESM : PDN Connectivity Request |
|
UE <-- NW |
RRC : RRC Connection Reconfiguration + NAS : Attach Accept + NAS : Activate Default EPS Bearer Context Req |
NAS EPS Mobility Management Message Type: Attach request (0x41)
0... .... = Type of security context flag (TSC): Native security context (for KSIasme)
.100 .... = NAS key set identifier: (4)
.... 0... = Spare bit(s): 0x00
.... .010 = EPS attach type: Combined EPS/IMSI attach (2)
EPS mobile identity
Length: 11
.... 0... = odd/even indic: 0
.... .110 = Type of identity: GUTI (6)
Mobile Country Code (MCC): Unknown (1)
Mobile Network Code (MNC): Unknown (01)
MME Group ID: 32769
MME Code: 0
M-TMSI: 0x00000001
UE network capability
Length: 4
1... .... = EEA0: Supported
.1.. .... = 128-EEA1: Supported
..1. .... = 128-EEA2: Supported
...0 .... = 128-EEA3: Not Supported
.... 0... = EEA4: Not Supported
.... .0.. = EEA5: Not Supported
.... ..0. = EEA6: Not Supported
.... ...0 = EEA7: Not Supported
0... .... = EIA0: Not Supported
.1.. .... = 128-EIA1: Supported
..1. .... = 128-EIA2: Supported
...0 .... = 128-EIA3: Not Supported
.... 0... = EIA4: Not Supported
.... .0.. = EIA5: Not Supported
.... ..0. = EIA6: Not Supported
.... ...0 = EIA7: Not Supported
1... .... = UEA0: Supported
.1.. .... = UEA1: Supported
..0. .... = UEA2: Not Supported
...0 .... = UEA3: Not Supported
.... 0... = UEA4: Not Supported
.... .0.. = UEA5: Not Supported
.... ..0. = UEA6: Not Supported
.... ...0 = UEA7: Not Supported
0... .... = UCS2 support (UCS2): The UE has a preference for the default alphabet
.1.. .... = UMTS integrity algorithm UIA1: Supported
..0. .... = UMTS integrity algorithm UIA2: Not Supported
...0 .... = UMTS integrity algorithm UIA3: Not Supported
.... 0... = UMTS integrity algorithm UIA4: Not Supported
.... .0.. = UMTS integrity algorithm UIA5: Not Supported
.... ..0. = UMTS integrity algorithm UIA6: Not Supported
.... ...0 = UMTS integrity algorithm UIA7: Not Supported
NAS EPS Mobility Management Message Type: Attach accept (0x42)
0000 .... = Spare half octet: 0
.... 0... = Spare bit(s): 0x00
.... .010 = Attach result: Combined EPS/IMSI attach (2)
GPRS Timer - T3412 value
GPRS Timer: timer is deactivated
111. .... = Unit: value indicates that the timer is deactivated (7)
...0 0000 = Timer value: 0
Tracking area identity list - TAI list
Length: 6
0... .... = Spare bit(s): 0x00
.00. .... = Type of list: list of TACs belonging to one PLMN,
with non-consecutive TAC values (0)
...0 0000 = Number of elements: 0 [+1 = 1 element(s)]
Mobile Country Code (MCC): Unknown (1)
Mobile Network Code (MNC): Unknown (01)
Tracking area code(TAC): 0x0001