1. The document describes the process of initial attachment for a user equipment (UE) with and without Control and User Plane Separation (CUPS). 2. Key steps include authentication, security setup between the UE and MME, session establishment between the MME and gateway nodes, and context setup between the eNodeB and MME. 3. The PCRF is also involved to provide QoS rules when a default bearer is established.

1. DNS Query for GW Selection
UE MME HSS DNS SGW PGW
eNodeB
S1AP: Initial UE Message
NAS: Attach Request:
IMSI; TAI; PDN type
S1AP: Downlink NAS Transport
NAS: Authentication Request
RAND, AUTN
NAS: Authentication Response
RES
NAS: Security Mode Complete
Dia: Authentication-Information-Request Answer
Authentication Information (EUTRAN-Vectors)
Dia: Update Location
MME Id; IMSI
Dia: Update Location Answer
APN; QoS; Charging Characteristics
Dia: Authentication-Information-Request
IMSI; Visited-PLMN-Id
PCRF
NAS: Attach Request:
IMSI; TAI; PDN type
NAS: Authentication Request
RAND, AUTN
S1AP: Uplink NAS Transport
NAS: Authentication Request
RES
NAS: Security Mode Command
S1AP: Downlink NAS Transport
NAS: Security Mode Command
S1AP: Uplink NAS Transport
NAS: Security Mode Complete
Authentication and
NAS Security
Activation
Initial Attach (I) – No CUPS

2. UE MME HSS DNS SGW PGW
eNodeB
GTPCv2: Create Session Request
MME F-TEID (S11); PGW IP-addr (S5-C); PDN type; IMSI;
bearer QoS; EBI
GTPCv2: Create Session Response
Cause (req acc); SGW F-TEID (S11); SGW F-TEID (S1-U); UE IP-add;
bearer QoS; PDN F-TEID (S5-C); PGW F-TEID (S5-U); EBI
GTPCv2: Create Session
Request
SGW F-TEID (S5-C); SGW
F-TEID (S5-U); PDN type;
IMSI; bearer QoS; EBI
GTPCv2: Create
Session Response
Cause (req acc); PGW
F-TEID (S5-C); PGW F-
TEID (S5-U); UE IP-add;
bearer QoS; EBI
S1AP: Initial Context Setup Req.
Bearer QoS; E-RABToBeSetup: QCI; SGW S1-
U IP+TEID;
NAS: Attach Accept
New GUTI; TA List, T3412 APN; Bearer QoS;
UE-IP-address;
NAS: Attach Complete
GTPCv2: Modify Bearer Request
eNodeB F-TEID (S1-U); EBI
GTPCv2: Modify Bearer Response
Cause; EBI;
S1AP: Initial Context Setup Response
eNodeB S1-U IP+TEID
PCRF
Dia: Control Credit Request
Initial_Request; Called-Station-
Id (APN); Subscription-ID
(IMSI); Default-EPS-Bearer-QoS
(QCI&ARP) ; QoS Information
(APN-AMBR)
Dia: Control Credit Answer
Initial_Request; Default-EPS-
Bearer-QoS (QCI&ARP) ; QoS
Information (APN-AMBR); Event-
Trigger
NAS: Attach Accept
New GUTI; TA List, T3412 APN; Bearer QoS;
UE-IP-address;
S1AP: Uplink NAS Transport
NAS: Attach Complete
Initial Attach (II) – No CUPS

3. Initial Attach (I) - CUPS
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Update Location Ack APN, QoS, Charging Characteristics
Create Session Request
MME F-TEID (S11), PGW IP-addr (S5-C),
PDN type, IMSI, bearer QoS, EBI
Create Session Request
SGW F-TEID (S5-C), SGW F-TEID (S5-U),
PDN type, IMSI, bearer QoS, EBI
PCEF Initiated IP-CAN Session Establishment
Called-Station-Id (APN); Subscription-ID (IMSI); Default-EPS-Bearer-QoS
(QCI&ARP) ; QoS Information (APN-AMBR)
Create Session Response
Cause (req acc); PGW F-TEID (S5-C); PGW F-TEID (S5-U); UE IP-add; bearer QoS; EBI
Sx Session Establishment Request
Sx Session Establishment Response
Sx Session Establishment Request
Sx Session Establishment Response
First Downlink Data (if not handover)
Update Location Request MME Id, IMSI, ME Identity
NAS: Attach Request
IMSI, TAI, PDN type
S1AP: Initial UE Message
NAS: Attach Request
Identity Request
Identity Response IMSI
Authentication Information Request IMSI, Visited-PLMN-Id
Identity Request/Response
IMEISV
ME Identity Check
Authentication Req / NAS Security Setup
RAND, AUTN
PGW-U
PGW-C
RAN SGW-C
MME SGW-U PCRF HSS
EIR
Authentication Information Answer EUTRAN-Vectors
Authentication Res / NAS Security Setup
RES

4. Initial Attach (II) - CUPS
PGW-U
PGW-C
RAN SGW-C
MME SGW-U PCRF HSS
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
RRC Connection Reconfiguration (Attach Accept)
GUTI, TA List, APN, Bearer QoS, UE-IP-address
RRC Connection Reconfiguration Complete (Attach Accept)
Initial Context Setup Response (Attach Accept)
eNodeB S1-U IP+TEID
Direct Transfer (Attach Complete)
Uplink NAS Transport (Attach Complete)
First Uplink Data
Modify Bearer Request
eNodeB F-TEID (S1-U), EBI
Modify Bearer Request
Modify Bearer Response
Sx Session Modification Request
Sx Session Modification Response
Sx Session Modification Request
Sx Session Modification Response
Modify Bearer Response
Cause, EBI
First Downlink Data
Notify Request
Notify Response
Initial Context Setup Request
Bearer QoS, E-RABToBeSetup, QCI,
SGW S1-U IP+TEID
(Attach Accept)
GUTI, TA List, APN, Bearer QoS, UE-IP-address
EIR
Create Session Response
Cause (req acc); SGW F-TEID (S11); SGW F-TEID (S1-U); UE IP-add;
bearer QoS; PDN F-TEID (S5-C); PGW F-TEID (S5-U); EBI
Sx Session Modification Request
Sx Session Modification Response