1 © Nokia 2018

WiFi Integration

in Evolution to 5G networks

Satish Kanugovi (satish.k@nokia.com)

WiFi Knowledge Summit, Bangalore

March 9, 2018

Outline

• Integrating WiFi Access into the 5G Core

• Multi-Access Edge Computing and WiFi Access

• Common Capacity Management Frameworks

- IETF - Multi Access Management Services (MAMS)

- 3GPP – Access Traffic Steering, Switching and Splitting (ATSSS)

Integrating WiFi Access into the 5G Core

• Non-3GPP access networks are connected to 5G core network via a Non-3GPP Inter-Working Function (N3IWF).

• The N3IWF interfaces to 5G core network control-plane functions and user-plane functions via N2 interface and N3 interface, respectively.

• Only Untrusted Non 3GPP Access is currently in scope, Trusted being discussed for R-16

Non-roaming architecture for 5G core network with non-3GPP accessSource: 3GPP TS 23.501

Untrusted Non-

3GPP AccessUE

N3IWF

3GPP

Access

Data Network

HPLMN

Non-3GPP

Networks

UPF

N3 N6

Y1

Y2

AMF SMF

N2

N2N4

N3

NWu

N11

N1

N1

5G Control Plane for WiFi Access

• UE gets an IP address via the non-3GPP access.

• UE initates IPsec Security Association (SA) with the selected N3IWF by initiating an IKE initial exchange

• UE initiates an IKE_AUTH exchange indicating the use of EAP (EAP-5G) signalling.

• The N3IWF responds with an IKE_AUTH response message which includes an EAP-Request/5G-Start packet and informs UE to encapsulated NAS messages within EAP-5G packets.

• Once the IPsec SA is established between the UE and N3IWF, "signalling IPsec SA“, all NAS messages between the UE and N3IWF are exchanged via this SA.

NAS

EAP-5G

IKEv2 IKEv2

NAS

N2

stack

N2

stackIP IP

Non-3GPP

IP

Non-3GPPLower

layers

Lower

layers

UEUntrusted non-3GPP

access networkN3IWF AMF

Nwu N2

RelayEAP-5G

NAS

IPsec IPsec

NAS

N2

stack

N2

stackIP IP

Non-3GPP

IP

Non-3GPPLower

layers

Lower

layers

UEUntrusted non-3GPP

access networkN3IWF AMF

Nwu N2

Relay

IKEv2 IKEv2

N2

stack

N2

stackIP IP

Non-3GPP

IP

Non-3GPPLower

layers

Lower

layers

UEUntrusted non-3GPP

access networkN3IWF AMF

Nwu N2

Control Plane before the signalling IPsec SA is established between UE and N3IWFSource: 3GPP TS 23.501

Control Plane after the signalling IPsec SA is established between UE and N3IWFSource: 3GPP TS 23.501

Control Plane for establishment of user-plane via N3IWFSource: 3GPP TS 23.501

5G User plane for WiFi Access

• Data, 5G PDUs, over the Non 3GPP access is sent inside the secure tunnel between UE and N3IWF

• UDP can be used as tunnelling protocol in IPsec for NAT traversal.

PDU Layer

GRE GRE

PDU

Layer

N3

stack

N9

stackIP IP

Non-3GPP

IP

Non-3GPPLower

layers

Lower

layers

UEUntrusted non-3GPP

access networkN3IWF

UPF(PDU

Session Anchor)

Nwu N3

Relay

N3

stack

N9

stack

Relay

N9UPF

IPsec IPsec

User Plane for Non 3GPP Access via N3IWFSource: Figure 8.3.2-1, 3GPP TS 23.501

Edge Computing –“Mobile” to “Multi Access”

• ETSI MEC is working on standards for enabling benefits of Edge Computing framework to applications

• In Phase 1, MEC (Mobile Edge Computing) focused on Edge Computing framework for Mobile (cellular) networks

• In Phase 2, Scope has evolved into a Multi Access Edge Computing Platform with support 3GPP and non-3GPP access technologies (WiFi and fixed) Overview of Multi Access Edge Computing [1]

Extending MEC to WiFi networks

• ETSI MEC Phase 1 has published Radio Network Information Service (RNIS) APIs for Applications take advantage of real time radio network information to improve service delivery

- http://www.etsi.org/deliver/etsi_gs/MEC/001_099/012/01.01.01_60/gs_MEC012v010101p.pdf

- MEC applies Analytics (e.g. Mashup) on information coming from multiple RATs and provide feedback (e.g. ETSI RNIS APIs) in a way suitable for use by applications

- Can be easily extended to support information exposure from additional RATs, like Wi-Fi, 5G, DSL, individually or in combination.

• ETSI MEC Phase 2 will extend the information exposure to other access technologies

• New Service to specify WiFi access information. Some examples of nature of information that could be exposed:

- BSS Load (station count, channel utilization, admission capacity)

- STA statistics (STA counters, BSS avg delay, etc)

- Estimated throughput UL/DL

- WAN metrics (DL speed/load, UL speed/load)

- STA RSSI

• Builds on existing and ongoing work from WFA e.g. Multi-AP Services, Data Elements and Hotspot 2.0.

WiFi + Cellular – Common Capacity Management

• Application QoE (quality of experience) varies with choice of access technology

• Performance depends on factors like radio conditions, user population, actual network

utilization

• Wi-Fi offers good capacity with small number of users which quickly degrades, low

throughputs and large unpredictable delays due to poor MAC efficiency.

• LTE offers predictable performance but capacity is limited by available licensed

spectrum

• Combining the best of WiFi and Cellular can deliver the best value from the network

IETF MAMS

• MAMS (Multi Access Management Services) is a framework for - Integrating different access network domains based on user plane (e.g. IP layer) interworking,

- with ability to select access and core network paths independently

- and user plane treatment based on traffic types

- that can dynamically adapt to changing network conditions

- based on negotiation between client and network

• The technical content is available as the following drafts*- Multi Access Management Services (MAMS) Framework – https://datatracker.ietf.org/doc/draft-kanugovi-

intarea-mams-framework/

- MAMS JSON definitions of Control Plane Messages: https://www.ietf.org/id/draft-agarwal-intarea-mams-protocol-json-00.txt

- MAMS User Plane Specification: https://tools.ietf.org/html/draft-zhu-intarea-mams-user-protocol-02

*Currently under review, Co-authors: Nokia, Intel, Broadcom, Huawei, AT&T, KT,

• MAMS functional elements

- Network Connection Manager (NCM)

• Intelligence in the network to configure network paths and user plane protocols based on client negotiation

• Gateway for common multi-network view, network policy input and Interface to Application Platforms

- Client Connection Manager (CCM)

• Negotiates client’s capabilities and needs with the NCM and configures network path usage

- NCM – CCM message exchange enables

• Dynamic selection of best network paths

• Flexible configuration of MADP protocols and parameters

• Overlay and Extensible messaging (e.g. JSON over WebSocket)

- Multiple Access Data Proxy (C/N-MADP)

• C-MADP handles user plane functions at the client and N-MADP at network.

• User plane distribution and aggregation across configured network paths.

• Supports any user plane protocols including existing IETF protocols like TCP, UDP, MPTCP, SCTP, QUIC, GRE, …

MAMS Architectural Framework

DSL/FIXED

ACCESS NODE

(ROUTER)

WI-FI ACCESS

NETWORK

(ACCESS

POINT)

ACCESS NETWORKS

DSL/FIXED

CORE

WLAN

CORELTE CORE

CORE NETWORKS

LTE ACCESS

NETWORK (ENB)

NETWORK

CONNECTI

ON

MANAGER

(NCM)

NETWORK

MULTI

ACCESS

DATA

PROXY

(N-MADP)

MAMS Enabled Network

APPLICATION

SERVER

CLIENT

CLIENT

CONNECTI

ON

MANAGER

(CCM)

CLIENT

MULTI

ACCESS

DATA

PROXY

(C-MADP)

5G

(GNB)

5G CORE

MEC

(Access Edge)

Core User Plane

Gateway

(multiple)

NCM and N-

MADP

instances

can be

hosted at

Access Edge

and/or Core

Gateways

MAMS

Control Plane

MAMS

User Plane

• Applications accessed via LTE core (cellular

service subscription and authentication) can

take advantage of Wi-Fi capacity in uplink

and downlink

• Flexibility in choosing Wi-Fi access even

when LTE core is used as IP anchor

• Support high bandwidth demanding video

downloads on LTE connections using Wi-Fi

DL

• Support LTE Core routed cloud video

content uploads using Wi-Fi UL

• MEC controls and monitors usage of Wi-Fi

access

MAMS at MEC integrating LTE and Wi-Fi networksUse case 1: Support high UL/DL BW applications with LTE [7]

WI-FI ACCESS

NETWORK

(ACCESS POINT)

ACCESS NETWORKS

WLAN

CORELTE CORE

CORE NETWORKS

LTE ACCESS

NETWORK (ENB)

(NCM) (N-MADP)

APPLICATION

SERVER

CLIENT

CLIENT

CONNECTION

MANAGER

(CCM)

CLIENT MULTI

ACCESS DATA

PROXY

(C-MADP)

MEC

• Enterprise improves its services by offloading

Uplink of Enterprise services to LTE uplink that

are then shunted across back to the enterprise

WLAN infrastructure

• All enterprise traffic stays local – avoids traversal

through operator core

• ‘Big’ gains in VoWiFi capacity

• Simple, scalable solution towards all-wireless

enterprise that leverages LTE

- Internet access possible through enterprise core

MAMS at MEC integrating LTE and Wi-Fi networksUse Case 2: Using LTE UL to improve QoE for ‘Wi-Fi’ Apps [7]

WI-FI ACCESS

NETWORK

(ACCESS POINT)

ACCESS NETWORKS

WLAN

CORELTE CORE

CORE NETWORKS

LTE ACCESS

NETWORK (ENB)

(NCM) (N-MADP)

APPLICATION

SERVER

CLIENT

CLIENT

CONNECTION

MANAGER

(CCM)

CLIENT MULTI

ACCESS DATA

PROXY

(C-MADP)

MEC

3GPP Access Traffic Steering, Switching and Splitting (ATSSS)

• 3GPP TR 23.793 has in its scope the study of architectural aspects and solutions for

extending the 5G System (5GS) to support Access Traffic Steering, Switching and

Splitting (ATSSS) between 3GPP and non-3GPP access networks.

• Initially, the study considers ATSSS solutions that enable traffic selection, switching and

splitting between NG-RAN and untrusted non-3GPP access networks.

• Subsequently, after the 5GS architecture is enhanced to support trusted non-3GPP

access networks.

Proposed Solutions in ATSSS TR 23.793 (0.2.0, work in progress)

Solution 1: Proposed architecture framework for ATSSS

UE Untrusted Non - 3GPP Access

3GPP Access

Data Network N3IWF

UPF

AMF SMF PCF AF

AUSF UDM

N2

N3

N3

N2 N14

N1 N15

N6

N4

N13

N12 N10 N8

N5 N7 N11

N9

Y1

Y2 N1 NWu

UE - AT3SF

UP - AT3SF

SM - AT3SF PC - AT3SF

UDR - AT3SF

N25

Virtual

Interface

NG-RAN

UPF-2

(optional)

UPF-1

(optional)

UPF-A

IP

5GWL

AN

Child PDU

session #1

UE

N6AMF

N2

N2

N3

N3

SMFN4N11

WLAN

AN

N3IWFChild PDU

session #2

Multi-Access

PDU session

Solution 2: Support of Multi-Access PDU Sessions

Traffic Distribution function

Traffic Recombination function

ATSSS Policy Enforcement function

Path performance measurement Path performance measurement

User plane

SMF

Link detection

Control plane

UE

Traffic Steering Switching & Splitting rules

PDU session data

ATSSS Traffic

Control function

PDU session data

UPF

ATSSS Traffic

Control function

Traffic Distribution function

Traffic Recombination

function

PCFATSSS Policy Control function

Traffic Steering Switching & Splitting policies

3GPP access

Non-3GPP access

N3

N3

N4

NCP

Encapsulation

NCP

Decapsulation

NCP

Decapsulation

NCP

Encapsulation

Solution 3: NCP based architecture framework for ATSSS

References

[1]MEC Introduction Slides, ETSI MEC

[2] MEC Deployments in 4G and Evolution Towards 5G, ETSI MEC Whitepaper

[3] 3GPP TS 23.501, System Architecture for the 5G System; Stage 2 (R15)

[4] 3GPP TS 23.502, Procedures for the 5G System; Stage 2 (R15)

[5] 3GPP TR 23.793, Study on Access Traffic Steering, Switching and

Splitting support in the 5G system architecture (R16)

[6] IETF MAMS Framework draft (under review) - http://www.ietf.org/id/draft-kanugovi-intarea-mams-framework-00.txt

[7] MAMS (Multi Access Management Services) framework for MEC, Broadband Forum Birds of a Feather Webinar - MEC Part 2, BBF2017.556