true fixed-mobile convergence (fmc) with 5g

True Fixed-Mobile Convergence (FMC) with 5G

@3g4gUK

Background Material

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https://www.3g4g.co.uk/5G/5Gtech_video0016.html

https://www.3g4g.co.uk/5G/5Gtech_video0014.html

Support of non-3GPP access

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• 3GPP TS 23.501:4.2.8 - Support of non-3GPP access

• The 5G Core Network supports connectivity of UEs via non-3GPP access networks, e.g. WLAN access networks

• The following types of non-3GPP access networks are defined:

1. Untrusted non-3GPP access networks;2. Trusted non-3GPP access networks (TNAN); 3. Wireline access networks.

Control plane function group

5GS Service Based Architecture (SBA)

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Data Network (DN)gNodeB

(NG-RAN)5G UE

User plane function

UPF

AMF SMF

NSSF NEF NRF AUSFFE PCFFEUDM AFUDR

FE

UDC

N1

N2

N3 N6

N4

Nnssf Nnef Nnrf Nudm Nausf Npcf Naf

AF Application FunctionAMF Access and Mobility management FunctionAUSF Authentication Server FunctionDN Data NetworkFE Front EndN3IWF Non-3GPP InterWorking FunctionNEF Network Exposure FunctionNRF NF Repository FunctionNSSF Network Slice Selection FunctionPCF Policy Control Function(R)AN (Radio) Access NetworkSEPP Security Edge Protection ProxySMF Session Management FunctionUDM Unified Data ManagementUDR Unified Data RepositoryUDSF Unstructured Data Storage FunctionUE User EquipmentUPF User Plane Function

Simplified 5GS SBA

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AMF SMF

UPF DN

N11

N4

N6

3GPP Access

N2

N3

N1(Air Interface)

HPLMN

HPLMN Home PLMN

Support of non-3GPP access

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Non-3GPP Access

Untrusted

Trusted

Wireline

5G Core (5GC)

3GPP Access

(NG-RAN)

Trusted and Untrusted Non-3GPP Access: General Concepts #1

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• The 5G Core Network supports both untrusted non-3GPP access networks and trusted non-3GPP access networks (TNANs).

• An untrusted non-3GPP access network shall be connected to the 5G Core Network via a Non-3GPP InterWorking Function (N3IWF).

• A trusted non-3GPP access network shall be connected to the 5G Core Network via a Trusted Non-3GPP Gateway Function (TNGF).

• Both the N3IWF and the TNGF interface with the 5G Core Network CP and UP functions via the N2 and N3 interfaces, respectively.


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• A non-3GPP access network may advertise the PLMNs for which it supports trusted connectivity and the type of supported trusted connectivity (e.g. "5G connectivity"). • Therefore, the UEs can discover the non-3GPP access networks that can

provide trusted connectivity to one or more PLMNs.

• The UE decides to use trusted or untrusted non-3GPP access for connecting to a 5G PLMN by using procedures not defined by 3GPP.


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• When the UE decides to use untrusted non-3GPP access to connect to a 5G Core Network in a PLMN:• the UE first selects and connects with a non-3GPP access network; and then• the UE selects a PLMN and an N3IWF in this PLMN. The PLMN/N3IWF selection

and the non-3GPP access network selection are independent.

• When the UE decides to use trusted non-3GPP access to connect to a 5G Core Network in a PLMN:• the UE first selects a PLMN; and then• the UE selects a non-3GPP access network (a TNAN) that supports trusted

connectivity to the selected PLMN. In this case, the non-3GPP access network selection is affected by the PLMN selection.

Untrusted Non-3GPP Access Architecture

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AMF SMF

UPF DN

N11

N4

N6

3GPP Access

N3IWF

UntrustedNon-3GPP

Access

N2

N2N3

N3

N1(Air Interface)

Y2

Y1

N1NWu

HPLMN

Non-3GPPNetworks

Based on 3GPP TS 23.501 Figure 4.2.8.2.1-1: Non-roaming architecture for 5G Core Network with untrusted non-3GPP access

5GS SBA with Untrusted Non-3GPP Access

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Data Network

(DN)gNodeB(NG-RAN)

5G UE

User plane

function

UPF

AMF SMF


FE

UDC

N1

N2

N3 N6

N4


N3IWFN2

N1

Y2

N3

Y1

NWu

Data Network

(DN)

User plane function

UPF

N6

Trusted Non-3GPP Access Network (TNAN)

Trusted Non-3GPP Access Architecture

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AMF SMF

UPF DN

N11

N4

N6

3GPP Access

TrustedNon-3GPP

Access Point

(TNAP)

N2

N3

N1

(Air Interface)

HPLMN

Based on 3GPP TS 23.501 Figure 4.2.8.2.1-2: Non-roaming architecture for 5G Core Network with trusted non-3GPP access

TrustedNon-3GPP

Gateway Function

(TNGF)

N3

N2

TnYt

N1

NWt

Ta

5GS SBA with Trusted Non-3GPP Access

©3G4G

Data Network

(DN)gNodeB(NG-RAN)

5G UE

User plane

function

UPF

AMF SMF


FE

UDC

N1

N2

N3 N6

N4


TNANN2

N1

Y2

N3

Yt

NWt

Data Network

(DN)

User plane function

UPF

N6

Introducing the Wireline Access Terminology #1

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• RG: The Residential Gateway (RG) is a device providing, for example voice, data, broadcast video, video on demand, to other devices in customer premises.

• 5G-RG: A 5G-RG is a RG capable of connecting to 5GC playing the role of a UE with regard to the 5G core. It supports secure element and exchanges N1 signalling with 5GC. The 5G-RG can be either a 5G-BRGor 5G-CRG.• 5G-BRG: The 5G-BRG is a 5G-RG defined in BBF.• 5G-CRG: The 5G-CRG is a 5G-RG specified in DOCSIS MULPI.

Introducing the Wireline Access Terminology #2

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• W-AGF: The Wireline Access Gateway Function (W-AGF) is a Network function in W-5GAN that provides connectivity to the 5G Core to 5G-RG and FN-RG.

• FN-RG: A Fixed Network Residential Gateway (FN-RG) is a RG that it does not support N1 signalling and it is not 5GC capable.

• W-5GAN: The Wireline 5G Access Network (W-5GAN) is a wireline AN that connects to a 5GC via N2 and N3 reference points. The W-5GAN can be either a W-5GBAN or W-5GCAN.• W-5GBAN: Wireline 5G BBF Access Network defined in BBF.• W-5GCAN: Wireline 5G Cable Access Network defined in CableLabs.

W-5GAN

Wireline Non-3GPP Access Architecture with 5G-RG

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AMF SMF

UPF DN

N11

N4

N6

3GPP Access

N2

N3

N1

Based on 3GPP TS 23.501 Figure 4.2.8.4-1: Non- roaming architecture for 5G Core Network for 5G-RG with Wireline 5G Access network and NG RAN

W-AGF

N3

N2

N1

Y4

5G-RG

W-5GAN

Wireline Non-3GPP Access Architecture with FN-RG

©3G4G

AMF SMF

UPF DN

N11

N4

N6

3GPP Access

N2

N3

Based on 3GPP TS 23.501 Figure 4.2.8.4-2: Non- roaming architecture for 5G Core Network for FN-RG with Wireline 5G Access network and NG RAN

W-AGF

N3

N2

N1

Y5FN-RG

5GS SBA with Wireline Access

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Data Network

(DN)gNodeB(NG-RAN)

User plane

function

UPF

AMF SMF


FE

UDC

N1

N2

N3 N6

N4


W-5GANN2

N1

N3

Y4

Data Network

(DN)

User plane function

UPF

N6

5G-RGFN-RG

Y5

N1

N5CW: Non-5G-Capable over WLAN #1

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• The devices that do not support 5GC NAS signalling over WLAN access are referred to as "Non-5G-Capable over WLAN" UEs, or N5CW UEs for short.

• A N5CW UE is not capable to operate as a 5G UE that supports 5GC NAS signalling over a WLAN access network, however, it may be capable to operate as a 5G UE over NG-RAN.

• Release-16 specifies 5GC architectural enhancements that enable N5CW UEs to access 5GC via trusted WLAN access networks.

N5CW: Non-5G-Capable over WLAN #2

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• Not all trusted WLAN access networks support 5GC access from N5CW UEs.

• To support 5GC access from N5CW UEs, a trusted WLAN access network must support a TWIF function.

• When a N5CW UE performs an EAP-based access authentication procedure to connect to a trusted WLAN access network, the N5CW UE may simultaneously be registered to a 5GC of a PLMN. The 5GC registration is performed by the TWIF function in the trusted WLAN access network, on behalf of the N5CW UE.

Trusted WLAN Access Network

5GC access from N5CW UEs Architecture

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AMF SMF

UPF DN

N11

N4

N6

3GPP Access

N2

N3

Based on 3GPP TS 23.501 Figure 4.2.8.5.2-1: Non-roaming and LBO Roaming Architecture for supporting 5GC access from N5CW UEs

Trusted WLAN

Interworking Function

(TWIF)

N3

N2

N1

YtN5CW UE

Trusted WLAN Access

Point (TWAP)

Yw

ATSSS: Access Traffic Steering, Switching and Splitting

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• New Access Traffic Steering, Switching and Splitting (ATSSS) functionality has been designed in Release 16, which allows traffic steering across multiple accesses at a finer granularities than a PDU session.

• The ATSSS feature is an optional feature in Release 16 both on the UE and the 5GC network

• ATSSS introduces the notion of Multi Access PDU session, a PDU session for which the data traffic can be served over one or more concurrent accesses (3GPP access, trusted non-3GPP access and untrusted non-3GPP access).

Non-3GPP Access

Architecture Reference Model for ATSSS Support

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AMF SMF

UPF DN

N11

N4

N6

3GPP Access

N2

N3

N1

Based on 3GPP TS 4.2.10-1: Non-roaming and Roaming with Local Breakout architecture for ATSSS support

N3

N2

N1

PCFN7

UE

MPTCP functionality

ATSSS-LL functionality

MPTCP Proxy

functionality

PMF

References

©3G4G

• 3GPP TS 23.501 v16.1.0: System Architecture for the 5G System; Stage 2 – Section 4.2 contains details regarding this topic

• WBA and NGMN Alliance: RAN Convergence Paper, August 2019• Broadband Forum – MR-427: 5G Fixed-Mobile Convergence, July 2018• Wireless Broadband Alliance (WBA) Whitepaper – WBA 5G Workgroup:

Unlicensed Integration with 5G Networks, October 2018• Metaswitch – The 5G Access Gateway Function (AGF): An Evolutionary

Tale, June 2019

https://www.ngmn.org/fileadmin/ngmn/content/downloads/Technical/2019/190903_RAN_Convergence_Paper.pdf

https://www.broadband-forum.org/download/MR-427.pdf

https://www.wballiance.com/wp-content/uploads/2018/10/Unlicensed-Integration-with-5G-Networks.pdf

https://www.metaswitch.com/blog/the-5g-access-gateway-function-agf-an-evolutionary-tale

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true fixed-mobile convergence (fmc) with 5g

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