A presentation on the 5G Core Network Architecture (based on 3GPP Release 15) and architectural enablers for cloud deployments

1. 5G Core Network
and the Cloud
Sridhar Bhaskaran • 13.12.2017
A Standards Perspective

2. Agenda
5G Requirements
Standards - Who is Doing What?
3GPP Standards
● Flavors of 5G Deployment
● Use Cases Driving the Need For a New
5G Core Network
● 5G Core Network Overview
● 5G Core Network Features
● Enablers for Cloud Deployment

3. 5G Requirements (from NGMN)

4. 5G Use Case Category Definition (NGMN)

5. Standards - Who is Doing What?
● Specification of a New Radio Technology, Spectrum, Waveforms etc - 3GPP RAN (RAN1, RAN2, RAN3, RAN4 and
RAN5)
● Specification of System requirements, architecture, management and security - 3GPP SA (SA1, SA2, SA3 and SA5)
● Specification of core network protocols - 3GPP CT (CT1, CT3 and CT4)
● Architecture for Multi Access Edge Computing - ETSI MEC
● Architecture, Framework and APIs for Network Function Virtualization - ETSI NFV
● Other alternative Radio Technologies
○ IEEE 802.11ax - WLAN
○ LoRA for LPWAN (IoT)

6. 3GPP Standards
(5G Core Network)

7. Flavors of 5G Deployment - Option 3
Reference: 3GPP RAN Plenary Document RP-161266

8. Flavors of 5G Deployment - Option 7
Reference: 3GPP RAN Plenary Document RP-161266

9. Flavors of 5G Deployment - Options 2
Standalone NR
Reference: 3GPP RAN Plenary Document RP-161266

10. Use Cases Driving New 5G CN
● Diverse use cases - one network cant fit all ⇒ Network Slicing.
○ Independent deployment and management of each slice
○ Ability to own and manage a slice from a different administrative domain (e.g 3rd party enterprise)
○ Same application but provided by different enterprises (e.g vending machines from Coke and Pepsi)
○ Support for vertical market deployments
● Plug and play deployment of new features ⇒ Network Interactions via APIs ⇒ Service Based Architecture.
● Control Plane - User Plane separation from day 1 ⇒ Enabling SDN - centralized CP/distributed UP.
● Application influence on traffic steering.
● Common authentication framework for any access (3GPP, WLAN, Wireline). Common core for any access (3GPP, WLAN, Wireline) ⇒ True
fixed-mobile convergence.
● Support for Ethernet and Unstructured PDU types allowing deployment of LAN services over 3GPP radio.
● Support for Edge Computing ⇒ Local Area Data Network (LADN), Uplink Classifiers and Branching Points with Multihomed IPv6.
● Reduced signalling between UE and Core Network for IDLE-ACTIVE state transition + Energy efficient state handling at UE ⇒ RRC Inactive.
● Architectural Enablers for Virtualized / Cloud based Deployments ⇒ Support for stateless NFs.

11. 5G Core Network Architecture Overview
PGW
MME
SGW
HSS
PCRF AAA
ePDG
SCEF
Untrusted non 3GPP
Access (e.g Public WiFI)
GTP
Diameter
● Interfaces exposed as APIs on control plane
● Common control plane protocol (HTTP 2.0 over TCP)
● Network function service registry - NRF
LTE - Evolved Packet Core (EPC) 5G Core Network (5GC)
IKEv2

12. 5G Core Network Features - Network Slicing
UE RAN MME SGW
PGW
(APN1)
PGW
(APN2)
PGW
(APN3)
● 1 UE - connect to one Dedicated Core Network (DCN)
● 1 DCN can support multiple applications (APN)
● Same application support in multiple DCNs require repeated
configurations for same APN but different DCN in DNS
UE RAN AMF
SMF1
SMF2
SMF3
UPF1 DN-1
UPF2 DN-2
UPF3 DN-3
● 1 UE - can connect to multiple core network slices
● Each slice identified by an S-NSSAI
● AMF is common to all slices UE uses
● SMFs specific to each slice
● SMFs selected via NRF specific to the slice (S-NSSAI)
● NRFs + SMFs can be in different administrative domain from AMF
● SMFs select UPF
● Traffic routing of each slice is independent and isolated
● RAN supports slicing at the radio
● Network Slice Selection Policies provided to UE to
select a slice for a given application
LTE - Evolved Packet Core (EPC) 5G Core Network (5GC)

13. 5G Core Network Features - LADN (Multi
Access Edge Computing)
Registration Area
LADN Service
Area1
LADN Service
Area2
UPF
Local
Area DN
● AMF provides the list
of LADNs available in
a Registration Area
during UE
registration to the
network
● UE activates
sessions towards the
LADN when entering
the service area

14. Architectural Enablers for Cloud Deployment
● Storage of Network Function and session state in a unstructured data storage function (UDSF).
○ Allows session state to be separated from signalling thus enabling stateless NFs
● From protocol based signalling ⇒ API based core network signaling interaction.
○ Allows new features to be developed by reusing APIs
○ Direct interaction with needed NF via API
○ API and service discovery via NRF
● Ability to change the TNL (Transport Network Layer) address to UE session state binding anytime.

15. Challenges in Cloud Deployment
● Network slicing involving parts of slices spanning across administrative boundaries may
require multi-domain orchestration and resource co-ordination.
● Multi-domain orchestration is an open research area.
● No standard APIs yet for cross cloud federation.
● Once resources are instantiated and VNFs are onboarded - communication between VNFs
spanning across administrative boundaries will be through standardized 3GPP service
based interfaces.
● 3GPP SA5 defining information model for network slicing - concept of Network Slice
Subnet (e.g Transport network could be a subnet).
○ 3GPP TR 28.801 and TS 28.530
● A standard resource model leading to standard API will be a step in the right direction
(atleast for cross domain orchestration for slicing)

16. 3GPP SA5 Slice Management Model

17. 3GPP 5G Core Network Specifications
● 5G System Requirements - TS 22.261
● 5G System Architecture - TS 23.501
● 5G System Procedures and Call Flows - TS 23.502
● 5G Security - TS 33.501
● 5G Network Slice Management - TS 28.530
● Latest specifications to be available after Dec 20-22, 2017 SA Plenary at Lisbon
● http://www.3gpp.org/ftp/Specs/archive/23_series/
● http://www.3gpp.org/ftp/Specs/archive/22_series/

18. 3GPP 5G Timeline

19. 3GPP Release 16 and Beyond
● Support for massive IoT - core network enhancements to support cellular IoT features in 5G
● Support for Ultra Reliable and Low Latency Communication (URLLC) - new QoS characteristics,
enhanced UPF placement logic, Enablers for ultra reliability
● Wireless Wireline Convergence
● Support for Enhanced Network Automation using Analytics
● Multicast and Broadcast support over 5G
● 5G LAN

20. Summary
1. 5G Core Network is a Paradigm
Shift
2. First truly cloud native
architecture
3. API based - Easy 3rd party
application integration
4. First truly converged core for all
access
5. Diverse use case support

21. Thank You