Nodes & Their Functions:
-
UE (User Equipment): Mobile, smartphone, 5G device
-
eNB (LTE eNodeB): 4G radio access (RAN)
-
gNB (5G gNodeB): 5G radio access (RAN)
-
MME (Mobility Management Entity): Signaling in LTE network
-
SGW (Serving Gateway): LTE data routing
-
PGW (Packet Gateway): LTE internet data access
-
HSS (Home Subscriber Server): User authentication
-
PCRF (Policy & Charging Rules Function): Policy management
-
IMS (IP Multimedia Subsystem): VoLTE calling & services
-
AMF (Access & Mobility Function): Signaling in 5G network
-
SMF (Session Management Function): 5G session handling
-
UPF (User Plane Function): 5G data forwarding
Interfaces & Their Functions:
-
Uu (UE ā eNB/gNB): Wireless air interface
-
X2 (eNB ā gNB): LTE ā 5G interworking
-
S1-MME (eNB ā MME): LTE control signaling
-
S1-U (eNB ā SGW): LTE user data
-
S11 (MME ā SGW): Session management
-
S5/S8 (SGW ā PGW): LTE data transport
-
S6a (MME ā HSS): User authentication
-
Gx (PGW ā PCRF): Policy control
-
Cx (IMS ā HSS): VoLTE authentication
-
Rx (IMS ā PCRF): VoLTE policy
-
SGi (PGW ā Internet): LTE internet access
-
N2 (gNB ā AMF): 5G control signaling
-
N3 (gNB ā UPF): 5G user data
-
N11 (AMF ā SMF): 5G session management
-
N4 (SMF ā UPF): User plane control
-
N6 (UPF ā Internet): 5G internet access
-
S3 (MME ā SGSN): 3G/4G interworking
-
Gn/Gp (SGSN ā GGSN): 3G data transport
Note: Read as
SGi : PGW to IMS
Consider IMS as an External Node/Application.
3GPP Standard Compliance in the Architecture
3GPP Reference Specifications Used:
-
3GPP TS 23.501: 5G System Architecture
-
3GPP TS 23.502: Procedures for the 5G System
-
3GPP TS 23.401: GPRS Enhancements for E-UTRAN Access (LTE EPC)
-
3GPP TS 23.060: General Packet Radio Service (GPRS) Architecture
-
3GPP TS 24.229: IMS Signaling for VoLTE
LinkedIn: 