ETSI GS F5G 004 V1.1.1 (2022-01)

Fifth Generation Fixed Network (F5G); F5G Network Architecture

DGS/F5G-004_ARCHITECTURE

General Information

• Status: Not Published
• Technical Committee: F5G - Fifth Generation Fixed Network
• Current Stage: 12 - Completion
• Due Date: 21-Feb-2022
• Completion Date: 31-Jan-2022

Standards Content (Sample)

GROUP SPECIFICATION
Fifth Generation Fixed Network (F5G);
F5G Network Architecture
Disclaimer
The present document has been produced and approved by the Fifth Generation Fixed Network (F5G) ETSI Industry
Specification Group (ISG) and represents the views of those members who participated in this ISG.
It does not necessarily represent the views of the entire ETSI membership.

2 ETSI GS F5G 004 V1.1.1 (2022-01)

Reference
DGS/F5G-004_ARCHITECTURE
Keywords
architecture, F5G
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: [phone]  Fax: [phone]

Siret N° 348 623 562 00017 - APE 7112B
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° w061004871

Important notice
The present document can be downloaded from:
http://www.etsi.org/standards-search
The present document may be made available in electronic versions and/or in print. The content of any electronic and/or
print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any
existing or perceived difference in contents between such versions and/or in print, the prevailing version of an ETSI
deliverable is the one made publicly available in PDF format at www.etsi.org/deliver.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
https://portal.etsi.org/TB/ETSIDeliverableStatus.aspx
If you find errors in the present document, please send your comment to one of the following services:
https://portal.etsi.org/People/CommiteeSupportStaff.aspx
Notice of disclaimer & limitation of liability
The information provided in the present deliverable is directed solely to professionals who have the appropriate degree of
experience to understand and interpret its content in accordance with generally accepted engineering or
other professional standard and applicable regulations.
No recommendation as to products and services or vendors is made or should be implied.
No representation or warranty is made that this deliverable is technically accurate or sufficient or conforms to any law
and/or governmental rule and/or regulation and further, no representation or warranty is made of merchantability or fitness
for any particular purpose or against infringement of intellectual property rights.
In no event shall ETSI be held liable for loss of profits or any other incidental or consequential damages.

Any software contained in this deliverable is provided "AS IS" with no warranties, express or implied, including but not
limited to, the warranties of merchantability, fitness for a particular purpose and non-infringement of intellectual property
rights and ETSI shall not be held liable in any event for any damages whatsoever (including, without limitation, damages
for loss of profits, business interruption, loss of information, or any other pecuniary loss) arising out of or related to the use
of or inability to use the software.
Copyright Notification
No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm except as authorized by written permission of ETSI.
The content of the PDF version shall not be modified without the written authorization of ETSI.
The copyright and the foregoing restriction extend to reproduction in all media.

© ETSI 2022.
All rights reserved.
ETSI
3 ETSI GS F5G 004 V1.1.1 (2022-01)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 7
3 Definition of terms, symbols and abbreviations . 8
3.1 Terms . 8
3.2 Symbols . 8
3.3 Abbreviations . 8
4 Business requirements for network architecture . 10
4.1 Business requirements overview . 10
4.2 Business requirements driving the F5G architecture . 10
5 Network architecture . 11
5.1 Architecture design principles . 11
5.1.1 Multi-Service Network Platform . 11
5.1.2 Dynamic and Flexible Service Creation . 12
5.1.3 Decoupling Service Plane and Network Plane. 12
5.1.4 AI-based Control, Management and Analytics . 12
5.2 Architecture overview . 12
5.3 Network topology and interfaces . 15
5.3.1 Network Overview . 15
5.3.2 Definition of Interfaces . 16
5.3.2.1 T interface . 16
5.3.2.2 T' interface . 17
5.3.2.3 T'' interface . 17
5.3.2.4 U interface . 17
5.3.2.5 U' interface . 17
5.3.2.6 B interface . 17
5.3.2.7 V interface . 17
5.3.2.8 V interface . 18
o
5.3.2.9 A10 interface . 18
5.3.2.10 A10' interface . 18
5.3.3 OTN Control Interfaces . 19
5.4 Key enabling features . 20
5.4.1 Network Slicing . 20
5.4.1.1 Introduction . 20
5.4.1.2 Concepts . 21
5.4.1.3 Network Slicing Applicability . 23
5.4.1.4 F5G Slicing Architecture . 24
5.4.1.5 Network Slice Management . 25
5.4.1.6 Traffic Steering in the Context of Slicing . 26
5.4.1.7 Wi-Fi Slicing . 26
5.4.1.8 PON Slicing . 26
5.4.1.8.1 Introduction . 26
5.4.1.8.2 User Group Oriented Slicing . 27
5.4.1.8.3 Service-Oriented Slicing. 27
5.4.1.9 OTN Slicing . 28
5.4.1.10 IP AggN Slicing . 30
5.4.2 Traffic Steering . 31
5.4.2.1 Overview . 31
ETSI
4 ETSI GS F5G 004 V1.1.1 (2022-01)
5.4.2.2 Traffic Steering Architecture . 31
5.4.2.2.1 High-level Framework . 31
5.4.2.2.2 Management Control and Analytics (MCA) functions . 32
5.4.2.2.3 Access Network Element Based Functions . 33
5.4.2.2.4 Aggregation Network Element Based Functions . 33
5.4.2.3 Example for Traffic Steering. 34
5.4.3 Separation of Services Plane and Underlay Plane . 35
5.4.3.1 Introduction . 35
5.4.3.1.1 Purpose of service and network separation. 35
5.4.3.1.2 Implementation of separation between service and network . 36
5.4.3.2 The Underlay Plane . 36
5.4.3.2.1 Introduction . 36
5.4.3.2.2 Bearer Technologies . 38
5.4.3.2.3 Summary and Analyses . 40
5.4.3.3 The Service Plane . 40
5.4.3.3.1 Introduction . 40
5.4.3.3.2 Traffic encapsulation for the Service Plane . 41
5.4.3.3.3 Signalling for the Service Plane . 41
5.4.4 The Aggregation Network Fabric . 41
5.4.4.1 IP/Ethernet Fabric . 41
5.4.4.2 OTN Fabric . 42
6 Network devices/equipment requirements . 44
6.1 Customer Premises Network requirements . 44
6.2 Optical Access Network requirements . 44
6.2.1 Access Network System Requirements . 44
6.2.2 ONU Requirements. 45
6.2.2.1 Functional Requirements . 45
6.2.3 OLT Requirements . 45
6.2.3.1 Functional Requirements . 45
6.2.3.2 Interface Requirements . 46
6.3 Optical Transport Network requirements . 46
6.4 IP Network requirements . 47
7 Network migration . 48
Annex A (informative): Change History . 50
History . 51

ETSI
5 ETSI GS F5G 004 V1.1.1 (2022-01)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The declarations
pertaining to these essential IPRs, if any, are publicly available for ETSI members and non-members, and can be
found in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to
ETSI in respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the
ETSI Web server (https://ipr.etsi.org/).
Pursuant to the ETSI Directives including the ETSI IPR Policy, no investigation regarding the essentiality of IPRs,
including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not
referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become,
essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its

Members. 3GPP™ and LTE™ are trademarks of ETSI registered for the benefit of its Members and of the 3GPP
Organizational Partners. oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and of the ®
oneM2M Partners. GSM and the GSM logo are trademarks registered and owned by the GSM Association.
Foreword
This Group Specification (GS) has been produced by ETSI Industry Specification Group (ISG) Fifth Generation Fixed
Network (F5G).
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
The F5G network, as described in ETSI GR F5G 002 [i.2], has committed to three characteristics for extending and
enhancing fixed networks, eFBB, FFC and GRE. These characteristics are derived from the F5G use cases ETSI
GR F5G 001 [i.1] that require these enhancements. To implement these characteristics, the F5G architecture has
introduced new design principles and new features. Such features include separation of data plane into Underlay Plane
and Service Plane, dual network fabrics for the Aggregation Network, comprised of an IP/Ethernet and an OTN fabric,
and the seamless and combined usage of PON and OTN, E2E slicing, etc. Based on these design principles and new
features, F5G can provide a variety of services for residential and enterprise customers over one physical network with
guaranteed SLAs. The new F5G architecture balances performance and operational efficiency through a higher degree
of flexibility and choice. Network services can be carried by an IP/Ethernet or an OTN fabric depending on the network
characteristics and the performance requirements and allowing for independent changes of the Underlay or Service
Planes to match the needs of applications, services or users. Using EVPN as the unified Service Plane technology
simplifies the service plane protocols and management. This Service Plane is easily programmable to adapt to market
needs and it supports different cloud-oriented Information and Communication Technology (ICT) architectures.
ETSI
6 ETSI GS F5G 004 V1.1.1 (2022-01)
1 Scope
The F5G Use Cases document ETSI GR F5G 002 [i.1] has defined many use cases for F5G. To support these use cases,
the network architecture will need to be simple, agile, optimized and intelligent. The present document defines the F5G
E2E network architecture and related network node requirements, including Customer Premise Network (CPN), Access
Network and Aggregation Network. F5G takes SDN/NFV into account for the network's control layer. The F5G
architecture will explore new network features like a seamless connection between Optical Transport Network and
Access Network, E2E full-stack slicing, etc.
The F5G end-to-end management architecture is considered out of scope for the present document.
The present document also specifies technical requirements for the network nodes and elements in the architecture. The
focus will be on Telecommunication networks in particular.
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://docbox.etsi.org/Reference/.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are necessary for the application of the present document.
[1] IETF RFC 8453: "Framework for Abstraction and Control of TE Networks (ACTN)".
[2] Recommendation ITU-T G.709/Y.1331: "Interfaces for the optical transport network".
[3] Recommendation ITU-T G.709.1/Y.1331.1: "Flexible OTN short-reach interfaces".
[4] Recommendation ITU-T G.709.3/Y.1331.3: "Flexible OTN long-reach interfaces".
[5] IETF RFC 8402: "Segment Routing Architecture".
[6] IETF RFC 8986: "Segment Routing over IPv6 (SRv6) Network Programming".
[7] IETF RFC 7209: "Requirements for Ethernet VPN (EVPN)". .
[8] IETF RFC 8584: "Framework for Ethernet VPN Designated Forwarder Election Extensibility".
[9] IETF RFC 4760: "Multiprotocol Extensions for BGP-4".
[10] IEEE 802.11ax™: "Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)
Specifications Amendment 1: Enhancements for High-Efficiency WLAN".
[11] Recommendation ITU-T G.9807.1: "10-Gigabit-capable symmetric passive optical network (XGS-
PON)".
[12] Recommendation ITU-T G.798: "Characteristics of optical transport network hierarchy equipment
functional blocks".
[13] Recommendation ITU-T G.873.1: "Optical transport network: Linear protection".
[14] Recommendation ITU-T G.873.2: "ODUk shared ring protection".
[15] Recommendation ITU-T G.873.3: "Optical transport network - Shared mesh protection".
ETSI
7 ETSI GS F5G 004 V1.1.1 (2022-01)
[16] Recommendation ITU-T G.8251: "The control of jitter and wander within the optical transport
network (OTN)".
[17] Recommendation ITU-T G.8201: "Error performance parameters and objectives for multi-operator
international paths within optical transport networks".
[18] IEEE 802.3.1™: "IEEE Standard for Management Information Base (MIB) Definitions for
Ethernet".
[19] IEEE 802.1Q™: "IEEE Standard for Local and metropolitan area networks--Bridges and Bridged
Networks".
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI GR F5G 002 (V1.1.1): "Fifth Generation Fixed Network (F5G); F5G Use Cases Release #1".
[i.2] ETSI GR F5G 001 (V1.1.1): "Fifth Generation Fixed Network (F5G); F5G Generation Definition
Release #1".
[i.3] ITU-T Study Group 15/Q18, G.fin-SA: "High speed fibre-based in-premises transceivers - system
architecture".
[i.4] IETF draft-ietf-ccamp-transport-nbi-app-statement: "sport Northbound Interface Applicability
Statement".
[i.5] IETF draft-ietf-teas-ietf-network-slices: "Framework for IETF Network Slices".
[i.6] IETF draft-ietf-teas-applicability-actn-slicing: "Applicability of Abstraction and Control of Traffic
Engineered Networks (ACTN) to Network Slicing".
[i.7] IETF draft-zheng-ccamp-yang-otn-slicing: "Framework and Data Model for OTN Network
Slicing".
[i.8] ITU-T Study Group 15/Q11 G.osu: "Optical Service Unit (OSU) path layer network".
[i.9] IETF draft-ietf-teas-enhanced-vpn: "A Framework for Enhanced Virtual Private Network (VPN+)
Services".
[i.10] IETF draft-bestbar-teas-ns-packet: "Realizing Network Slices in IP/MPLS Networks".
[i.11] ETSI GR IPE 005: "IPv6 Enhanced Innovation (IPE); IPE_5G Transport and Cloud and IP
network Convergence".
[i.12] IETF RFC 8655: "Deterministic Networking Architecture".
[i.13] IETF RFC 2702: "Requirements for Traffic Engineering Over MPLS".
[i.14] IETF RFC 3209: "RSVP-TE: Extensions to RSVP for LSP Tunnels".
[i.15] IETF draft-ietf-spring-resource-aware-segments: "Introducing Resource Awareness to SR
Segments".
[i.16] IEC 61158: "Industrial communication networks - Fieldbus specifications".
[i.17] ETSI GS F5G 006: "End-to-End Management and Control of F5G Networks".
ETSI
8 ETSI GS F5G 004 V1.1.1 (2022-01)
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:
application list: list of applications and the associated attributes to identify the application in a network element
EtherCAT: Ethernet for Control Automation Technology is an Ethernet-based fieldbus system
NOTE: The protocol is standardized in IEC 61158 [i.16] and is suitable for both hard and soft real-time
computing requirements in automation technology.
network slice: logical network that achieves specific service requirements
3.2 Symbols
Void.
3.3 Abbreviations
For the present document, the following abbreviations apply:
AI Artificial Intelligence
API Application Programming Interface
ARPU Average Revenue Per User
ASG Access Service Gateway
BGP Border Gateway Protocol
BNG Broadband Network Gateway
BSS Business Support System
BYOD Bring You Own Device
CE Customer Equipment
CPE Customer Premises Equipment
CPN Customer Premises Network
CPN-A CPN Agent
CPU Central Processing Unit
DC Data Centre
DC-GW Data Center Gateway
DSCP Differentiated Services Code Point
E2E End-to-End
E-CPE Enterprise CPE
eFBB enhanced Fixed BroadBand
ETH Ethernet
EVPN Ethernet VPN
FEC Forward Error Correction
FFC Full Fibre Connection
FlexO Flexible Optical transport network
FTTH Fibre-To-The-Home
FTTR Fibre-To-The-Room
GEM GPON Encapsulation Mode
GMPLS Generalized Multi-Protocol Label Switching
GPON Gigabit Passive Optical Network
GRE Guaranteed Reliable Experience
ICT Information and Communication Technology
IE Industrial Equipment
IP RAN IP Radio Access Network
IP Internet Protocol
IPTV Internet Protocol Television
IT Information Technology
ETSI
9 ETSI GS F5G 004 V1.1.1 (2022-01)
L2VPN Layer 2 VPN
LAN Local Area Network
LSP Link State Protocol
MAC Media Access Control
MAN Metropolitan Area Network
MEF Metro Ethernet Forum
MP-BGP Multiprotocol Extensions for BGP
MPLS Multiprotocol Label Switching
MS-OTN Multi-Service OTN
NAT Network Address Translation
NFV Network Function Virtualisation
NMS Network Management System
NSI Network Slice Instance
NSP Network Service Provider
O&M Operation and Maintenance
OAM Operation, Administration and Maintenance
OAM&P Operation, Administration, Maintenance and Provision
ODN Optical Distribution Network
ODU Optical Data Unit
OLT Optical Line Terminal
OMCI ONU Management and Control Interface
ONU Optical Network Unit
OSS Operations Support System
OSU Optical Service Unit
OTN Optical Transport Network
OTU Optical Transport Unit
OTUCn Optical Transport Unit-Cn
pBNG physical Broadband Network Gateway
PBX Private Branch Exchange
PC Personal Computer
PCS Physical Coding Sublayer
PDH Plesiochronous Digital Hierarchy
PE Provider Edge
PHY Physical layer
POL Passive Optical LAN
PON Passive Optical Network
PPPoE Point-to-Point Protocol over Ethernet
QoE Quality of Experience
QoS Quality of Service
RFC Requests for Comments
RG Residential Gateway
SDH Synchronous Digital Hierarchy
SDN Software Defined Networking
SLA Service Level Agreement
SME Small and Medium Enterprises
SRv6 Segment Routing over IPv6
T-CONT Traffic Container
TDM Time Division Multiplexing
TDMA Time Division Multiple Access
TID Traffic IDentifier
TOS Type Of Service
VCPE virtual Customer Premises Equipment
VLAN Virtual LAN
VNF Virtual Network Function
VNO Virtual Network Operator
VPN Virtual Private Network
VR Virtual Reality
VxLAN Virtual extensible Local Area Network
WAN Wide Area Network
WDM Wavelength-Division Multiplexing
WMM Wi-Fi multimedia
XC Cross-Connect
ETSI
10 ETSI GS F5G 004 V1.1.1 (2022-01)
XGS-PON 10-Gigabit-capable Symmetric PON
NOTE: Also known as symmetric 10G-PON.
YANG Yet Another Next Generation data modelling language
4 Business requirements for network architecture
4.1 Business requirements overview
When implementing a use case, the business requirements may be separated into a Physical Layer, a Network Layer and
an Application and Management Layer. The focus of the present document is the F5G network architecture. This clause
will summarize the business requirements of the network layer. However, this clause may also illustrate system-level
requirements essential to network nodes and equipment for the F5G use cases. Other requirements not deduced from the
F5G use cases may also be considered, such as network evolution trends.
4.2 Business requirements driving the F5G architecture
• Dual-Gigabit Networks:
The dual-Gigabit networks are represented by 5G mobile and fixed multi-gigabit optical networks (F5G),
which provide fixed and mobile gigabit single user access capabilities. The dual-Gigabit network features
ultra-high bandwidth, ultra-low latency and enhanced reliability. That means dual 5G and F5G networks need
to be built for new application scenarios beyond the traditional applications. It is a key element for developing
the digital economy, the digital society and the digital government.
• Rich set of Applications and Services for Different Market Segments:
The F5G architecture needs to support a rich and diverse set of application and service scenarios for a wide
range of customers profiles including home users, large, medium, and small enterprises and specific vertical
industries. Those applications and services for the different markets are ideally supported on the same
infrastructure for improved operational efficiency of communication and networking services. This
multi-service network shall allow flexible and dynamic service creation, development and deployment.
• F5G Infrastructure Convergence and Consolidation:
In the current fixed network business, the networking services are provided with dedicated networks and
shared best-effort network infrastructure using copper- and fibre-based access networks. Consolidating and
converging the fixed network infrastructure requires the overall infrastructure to enable a seamless connection
between network segments (access, aggregation and core) and differentiate the services required by the
different market segments and applications. The differentiation is expected over several dimensions, including
bandwidth, latency, reliability, end-to-end delay assurance, and convergence through dynamic service
awareness on a single, converged and agile management plane.
Also, studies show that enterprises from medium to small scale have a very diverse set of networking service
requirements and are often co-located with other SMEs and residential housing. Sharing infrastructure on
various levels is a suitable way of increasing operational efficiency.
• Converged Application Needs:
The line between home and enterprise networks is blurring since many more of those that work from home
offices require enterprise-grade infrastructure. Also, industries and education institutions have moved more
online and have massively digitized their processes, requiring the proper networking technology. On the other
hand, some enterprises encourage Bring Your Own Device (BYOD), and some applications that the workforce
are using are based on what they use at home. Also, enterprise networks are required to support residential
oriented methods of working and processes, including on-demand ordering of communication services.
ETSI
11 ETSI GS F5G 004 V1.1.1 (2022-01)
• Shift of Broadband Service Requirements:
So far, specifically for the residential markets, the services focus on the Internet Access Bandwidth. Also, in
the enterprise markets, an important focus is on network bandwidth and reliability. For F5G, the assumption is
that bandwidth is no longer the only dimension and that there is a shift from bandwidth to user experience to
improve ARPU. This implies that the network needs to be more service-aware. Separation and isolation of user
traffic from each other are a necessary mechanism to deal with guaranteed SLAs (e.g. through E2E slicing).
More experience-based network policies are required to support more scenario-based broadband products for
home, enterprise and verticals.
• Growing beyond Traditional Telecommunication:
The F5G architecture shall enable a wide range of services and functionalities, namely addressing specific
vertical industries and other needs that support new business areas. For example, the functionality of E2E
slicing and time-critical communication enables a larger set of industrial applications. In addition, the F5G
architecture should support Passive Optical LAN (POL) as carrier-grade technology for campus and enterprise
environments with the benefits of saving equipment rooms, having high-quality management capabilities,
saving energy through passive optical technologies, removing radiation, and enhancing networking services in
the customer premises.
• Increased Operational Efficiency:
The F5G architecture aims to improve operational efficiency by improving the quality of experience and better
control over the quality of the services provided, such that potential user requirements are detected early and
can be reacted upon. Integrating artificial intelligence and machine learning mechanisms into the F5G
architecture will enable improved efficiency and more accurate network planning in terms of quality and
capacity extension.
The F5G architecture is a unified architecture, which simplifies the O&M of the network. Decoupling the
service plane and underlay plane using fabric networking simplifies and decouples capacity expansion from
the service needs and improves bandwidth efficiency. Automatic operation and model-driven management
simplify the interaction with different IT systems in the operator domain.
• Security and Privacy:
The fixed network shall be a trusted infrastructure, requiring that the F5G architecture solves security and
privacy challenges. Secured and privacy-aware networks and services are important for customer's trust in the
network and make it a prerequisite for digitalization of industries and the society.
NOTE: The present document addresses only peripheral security and privacy topics, but they are addressed in
detail by other documents of the ETSI ISG F5G.
5 Network architecture
5.1 Architecture design principles
5.1.1 Multi-Service Network Platform
Multiple services for multiple customer types can be deployed based on the currently deployed broadband network
architecture. However, it is not flexible, the deployment takes time, and the different customer requirements are difficult
to fulfil cost-effectively. To enable flexible service deployment, SDN and NFV were introduced for network flexibility
as tools to migrate fixed network architecture towards an SDN and NFV enabled F5G network architecture. SDN
centralizes the control plane function and provides a concentrated network management functions. The management
plane is now called the Management, Control and Analytics (MCA) plane; it enables more flexible and more efficient
traffic route selection than a fully distributed control plane. NFV uses the virtualization technologies and cloudification
to virtualize entire classes of network node functions into functions that are either stand alone or chained together to
provide a communication service. This is especially beneficial for computing-based network functions, which can be
easily deployed on IT-oriented cloud infrastructures.
ETSI
12 ETSI GS F5G 004 V1.1.1 (2022-01)
NFV enables more flexibility to run the network functions and makes it easier to upgrade and enhance network services
dynamically. The F5G architecture supports processing elements wherever needed including edge computing. However,
the network's primary function is transporting bits at high speed, which means the base functionality of networking still
requires major hardware support.
The multi-service network platform needs mechanisms to isolate a certain type of service traffic from other traffic. The
platform should support guaranteed quality of service and a wide range of diverse services.
5.1.2 Dynamic and Flexible Service Creation
The F5G architecture is expected to support eFBB, FFC and GRE, which means ten times more speed, ten times more
dense connections and ten times better SLAs. Besides fundamental features like SDN and NFV, the F5G architecture
focuses more on flexible service enabling, reliable network performance guarantees, and autonomous service
deployment.
The assumption is that customers can order or change their services on demand through a user interface (portal or API)
to the OSS/BSS, which requires the Service Plane to be more flexible to adapt to a particular customer need.
5.1.3 Decoupling Service Plane and Network Plane
Therefore, broadband services shall be decoupled from the underlying network infrastructure. The decoupling allows
for the independent upgrade of the network infrastructure without any effect or changes on the service plane. Also, the
services can be adapted and changed without changing the basic network infrastructure. However, certain
interdependencies will still exist, specifically in terms of what resources on the underlay can be used to provide a
particular service. Also, in the cases of underlay network failures, these may affect the service quality.
5.1.4 AI-based Control, Management and Analytics
Artificial Intelligence shall be introduced on the Management & Control plane, making it a Management, Control &
Analytics Plane, enabling more intelligent detection of faults and QoE degradation, network behaviour analysis and
reaction to poor performing networks.
5.2 Architecture overview
Based on SDN and NFV principles, the F5G network architecture decouples services from the underlying physical
network. Figure 1 illustrates an overview of the three planes of the F5G network architecture.
ETSI
13 ETSI GS F5G 004 V1.1.1 (2022-01)

Figure 1: F5G network architecture
The F5G network architecture comprises three planes, an Underlay Plane, a Service Plane and a Management, Control
& Analytics (MCA) Plane.
• Underlay Plane:
This is fundamentally the physical network plane, which comprises physical network nodes. The Underlay
Plane provides connections and dynamic programmable path selection under the control of the F5G controller
in the MCA Plane. The network switching capacity shall scale without interfering with the Service Plane.
The Underlay Plane has four segments, Customer Premises Network (CPN), Access Network (AN),
Aggregation Network and Core Network. Various Technologies are used in the CPN, depending on the
end-user requirements. For example, in Home Access, Wi-Fi 6 and FTTR can be introduced as new
technologies, while Enterprise Access can benefit from POL to gain easy deployment and high bandwidth.
OTN can also be deployed in the CPN for customers requiring high-quality VPN service. The Access Network
shall be based on XGS-PON technology and OTN, depending on customer type and service delivered. The
Aggregation Network has two parallel fabrics, an IP/Ethernet fabric and an OTN fabric. The IP/Ethernet fabric
comprises spine switches, while OTN fabric is comprised of OTN nodes. For the actual deployment of
IP/Ethernet or OTN fabrics, there could be multiple physical fabrics of the same type co-existing in one
network. Both fabrics have a common Aggregation Edge handover point to the Core Network. There might be
multiple tunnels between Access Network and Aggregation Edge, which go over either the IP/Ethernet fabric
or the OTN fabric. There may be multiple paths through different nodes for differentiated SLA tunnel
instances in one fabric. Typically, there is only one tunnel instance for a certain SLA. The Access Network
connects both IP/Ethernet fabric and OTN fabric.
The Underlay Plane and the associated network nodes shall support network slicing.
• Service Plane
This plane provides service connectivity for customers and the broadband service above. Compared with
coarse granularity tunnels of the Underlay Plane, service connections on the Service Plane can be dynamically
created when triggered by protocols, e.g. PPPoE, or configured from the MCA Plane.
ETSI
14 ETSI GS F5G 004 V1.1.1 (2022-01)
A Service Access Point (SAP) provides customer service access. A Service Processing Point (SPP) performs
L1/L2/L3 service processing, which may be enhanced by Edge Computing. A Service Mapping Point (SMP) is
where traffic is directed to proper underlay fabric and channels. An Access Network typically contains SAP,
SPP and SMP. Besides providing the access function, it also identifies services, adds or removes
encapsulations, and directs the traffic to the proper underlay fabric and channels. An Aggregation Edge
typically contains SPP and SMP, because it needs to perform service-specific processing and egress/ingress
traffic mapping to appropriate underlay tunnel
...