5G és ami mögötte vanmit kell tudnia a backhaul-nak?

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Content/Agenda

01 Mobile network evolution

02 IP & Transport network

requirements for 5G use-cases

03 Heading to SDN – L0-L3 Evo

04Application controlled IP &

Transport networkinfrastructures

System Architecture Evolution

3

Circuit-only Circuit/Packet Packet-only

Voice, SMS

(Data)Voice, SMS

Data

Data, voice,

video,

messaging

GSM GPRS, UMTS EPS

Overall simplification, flat architecture

GGSN

NodeB

SGSN

RNC

GGSN

NodeB

SGSN

RNC

GGSN

RNC

NodeB

SGSN

SAE GW

eNodeB

Co

ntro

l Plan

e

Use

r Plan

e

MME

Release 6Release 7

Direct Tunnel

Release 7Direct Tunnel

RNC in NodeB

Release 8

SAE & LTE

Control and User Plane Separation of EPC nodes (CUPS)

4

Serving

Gateway-C

PDN

Gateway-CTDF-C

Operator s IP

Services

Serving

Gateway-U

PDN

Gateway-UTDF-U

S11 S4-C

S5/8-C

Gn/Gp-C

S2a-C

S2b-C

Gx Gy GzGw S6b Sd Gyn Gwn Gzn

Sxa Sxb Sxc

S12

S4-U

S1-U

S5/8-U

Gn/Gp-U S2a-U S2b-U

SGi SGi

Architecture introduced in Release 14

Reduce latency on application services

Supporting increase of Data Traffic (distributed user plane nodes)

Locating and scaling CP and UP resources of the EPC independently

Independent Evolution of CP and UP functions

Enabling SDN to deliver User Plane data more efficiently (network slicing?)

Cloud-RAN CONCEPT

5

C-RAN

Centralized baseband units with potential for pooled baseband

CPRI interconnect

Enables CoMP and other LTE-A

features

Not virtualized

Traditional D-RAN

Co-located BBU/RRU

Dedicated BBUs

Challenging for CoMP

Cloud-RAN

Virtualized baseband

CPRI, eCPRI, IEEE 1914.3 (Radio

over Ethernet)

New functional split CU/DU/RU (8

split options?!)

BBU

Site A

BBU

Site B

BBU

Site C

Site A

Site B Site C

Front

Haul

Central Office

BBUBBU

Site A

Site B Site C

Front

Haul

Mini-Data Center

BBUvBBU BBUCU/DU

Enhanced Radio protocol stacks

6

eCPRI protocol stack over IP/EthernetCPRI protocol stack

User PlaneControl &

Management PlaneSYNC

IQ Data

Time Division Multiplexing

Electrical Transmission Optical Transmission

Vend

or S

pecific

Eth

ern

et

HD

LC

L1 Inb

and

Pro

toco

l

Well defined in CPRI

• UMTS ; CPRI V1 and V2

• Wimax ; CPRI V3

• LTE ; CPRI V4

• GSM ; CPRI V5

Fully spcified in CPRI

Informative only, except

clock rate

Level of specification

Layer 2

Layer 1

Ethernet PHY

Ethernet MACEthernet

OAM

ICMPIP

User

DataReal-Time

Control

Other

eCPRI

servicesC&M

e.g.

SNMP

UDP, TCP,

SCTP, etc.UDP

PTP

SynchronizationConnection

OAM

UDP

eCPRI protocol layer

IPSec

VLAN (priority tag) MACsec

SyncE

eCPRI Services

5G SA architecture

7

NSSF AUSF UDM NEF NRF

AMF SMF PCF AF

UE(R)AN

NG-RAN, FixedUE

UPFDN

Nnssf Nausf Nudm Nnef Nnrf

NafNpcfNsmfNamf

N1

N2 N4

N3

N9

N6

AUSF Authentication Server Function

AMF Access and Mobility Management Function

AF Application Function

DN Data Networks

SMF Session Management Function

NEF Network ExposureFunction

NSSF Network Slice Selection Function

NRF Network Repository Function

PCF Policy Control Function

UPF User Plane Function

(R)AN (Radio) Access Network

APIs (HTTP/JSON)

Control

Data

IP & Transport network requirements

8

Profile Protocol Bandwidth Security Delay JitterFrequency

syncTime/Phase

sync

Backhaul EPC/5GC – CU

S1/NGEthernet

DL: 4 GbpsUL: 3 Gbps

IPsec< 8 ms eMBB< 1 ms for uRLLC

NA

Radio interface:±50ppb

BS backhaulinterface: ±16ppb

FDD: NA

TDD (30KHzsubcarrier): 1,5 µs

TDD (120 KHzSC): 0,4 µs

uRLLC: nx100ns

Positioning: 1 µs

High accuracypositioning: ~130 ns

Midhaul CU– DUSplit-RAN

F1Ethernet

DL: 5 GbpsUL: 4 Gbps

IPsec< 8 ms eMBB< 1 ms for uRLLC

< 5% of delay

CoordinationeNB/gNB – gNB

(neighboring)

X2/XnEthernet

DL: 4 GbpsUL: 3 Gbps

IPsec < 5 ms NA

Fronthaul DU – RRU

eCPRI Ethernet

DL: 20-25 GbpsUL: 20-25 Gbps

IPsecMACsec

<100µs < 5% of delay

FronthaulBB – RF (RRH)

not splitted RANCPRI

DL: 236 GbpsUL: 236 Gbps

NA <100µs < 2% of delay

Crosshaul (X-haul)DU – DU (neighboring)E-RAN* Coordination

E5Ethernet

DL: 4 GbpsUL: 3 Gbps

MACsec< 60 µs(E-RAN)

NA

The importance of phase synchronization

9

LTE-TDD / 5G NR-TDD On-The-Top servicesAvoiding interference

OTDOA CA

eMBMS eICIC

Sync specification (ITU-T G.8271):- Frequency synchronization accuracy within 50ppb (10-9)- Phase:

➢ TDD (level of accuracy:4): TE < 1,5 µs (E2E) ➢ Carrier Aggregation (level of accuracy 6A): TE < 260 ns (rel)

GNSS Vs. Network-Wide distributed sync

10

GNSS/GPS deployment at each and every mobile site▪ Today GNSS/GPS continues to satisfy the market’s timing requirements

➢ Reliability of GNSS/GPS in urban canyons is a major concern due to limited signal availability

➢ GPS is also extremely vulnerable to jamming and spoofing▪ Full-Time support is required for TDD -> PTP+SyncE/SyncµWbackup

Network-wide sync distribution–Accuracy, stability, reliability▪ GNSS based highly accurate and stable (Cesium) sync source (ePRTC)▪ Sync distibution network capabilities - PTP

➢ Sync distribution to BTSs with small distortion➢ Backup for GNSS/GPS signal loss

▪ Provides stability in combination with SyncE (frequency sync)

Access network options for gNB/BTS connectivities

11

WDM Aggregation Passive WDM DOCSIS 3.1NG-PON2

NG-Microwave technology options for LAST mileconnectivities

12

Microwave technology evolution:▪ Modulation: 4 QAM -> 4096 QAM▪ Increased Capacity:

➢ Vertical & horizontal polarization (XPIC)➢ Bonding radio links

▪ Increased Efficiency:➢ Dual-band➢ Adaptive modulation

Frequency bands 6 -15 GHz 18 - 42 GHz 60 GHz 70 - 80 GHz 100 - 150 GHz

Channel blocks ~ 750MHz ~ 2,2 GHz ~ 7 GHz ~ 10 GHz ~ nx 10 GHz

Bandwidth 0,8Gbps 1Gbps nx 1Gbps 10Gbps nx 10Gbps

Evolution of IP Transport UnderlayToday: IP/MPLS

13

Use cases

Tunneling encapsulation for servicesTraffic Engineering

Advantages

Widely deployed, mature technologyStandard encapsulation (label stack) for different services: IPv4/IPv6 VPNs, L2 transport… (unlike application specific overlay tunnels e.g. GRE or L2TP)

Disadvantages

Uses hop-by-hop signaled tunnels▪ Requires additional signaling protocols (LDP, RSVP-TE)▪ Tunnel states to be maintained in all intermediate routers along the path

(scalability issue in large traffic-engineered networks)Deployed as a backbone technology, not end-to-end▪ LERs are mandatory tunnel endpoints, thus touchpoints for service

provisioning▪ This drives the integration of most network functions into the LERDepends on IPv4

Evolution of IP Transport UnderlayEmerging trend: Segment Routing over MPLS

14

Use case

Offers similar capabilities as IP/MPLS, but addresses its drawbacks by usingsource routed tunnels – no tunnel state in the intermediate routers

Advantages

Uses existing label stack technology▪ Readily supported by most vendorsSimple coexistence with IP/MPLS

Disadvantages

It can be only deployed across the MPLS domain, not end-to-end▪ Only addresses the scalability issue of Traffic Engineering, does not

offer better service flexibilityOnly a subset of the 20-bit MPLS label space is available for segmentencoding▪ May introduce a different kind of scale limitationDepends on IPv4

Evolution of IP Transport UnderlayEmerging trend: Segment Routing over IPv6

15

Use case

Offers similar capabilities as SR-MPLS, but uses IPv6 underlay with modifiedheaders instead of MPLS label stack

Advantages

Tunnels can be set up end to end between services, wherever IPv6 connectivity is available („backwards compatible” with native IPv6 forwarding: supports direct or indirect IPv6 next hops)▪ This will be required for moving services into the cloud and simplifying

IP transport network functionality128-bit IPv6 address is available for segment encoding – No scale limitationSimplified protocol stack (removal of MPLS layer)Will not prevent complete IPv4 phase-out in long term

Disadvantages

Limited vendor support today▪ SRv6 header support is a new feature to be implemented in the

forwarding plane▪ Standards are still evolving

Evolution of IP Transport Overlay and VPN Services

16

L3VPN L2VPN p2pL2VPN multipoint

(VPLS)

Discovery

Signaling

Forwarding info

Transport

MP-BGP

(vpnv4/vpnv6)

MP-BGP

(vpls)

MP-BGP

(vpls)

LDPLDP

Manual

None (p2p)MAC learning /

flooding

MPLS

Today

Diverse VPN solutions

Evolution of IP Transport Overlay and VPN Services

17

EVPN supporting both L2 and L3 payload

Discovery

Signaling

Forwarding info

Transport

MP-BGP

(evpn)

Multiple options: MPLS, VXLAN, Segment Routing

Tomorrow

Unified solution forflexibility

Network Slicing

18

Application-specific dynamic virtual networks with different SLA guarantees over a sharedphysical infrastructure (e.g. eMBB, mMTC, URLLC slices in mobile backhaul)

Purpose

Possible solutions at different layers FlexEthernet

Layer 1 (bit level) separation and resource reservation

Enables ultra-low latency tunnels, bypassing packet switching mechanisms

Traffic Engineeredtunnels

Layer 1/2/3 level separation and resource reservation

GMPLS/MPLS: RSVP-TE/OSPF-TE, SR-TE

VPNsLayer 2/3 traffic separation; limited guarantees (no e2e resource reservation)

Widely used for today’s applications

Probably will be relevant in the next years

Exact use cases, requirements, best practices and standards are still in the research stage

Vendors generally wait for real market demand and settling of standards

Depends on real-time intent-based control framework

Status

Centralized DCRegional DC

Site

Multi-Access

EdgeComputing Site

Architectural changes in Ip & Transportnetworking infrastructure

19

vRAN

CPFs

Fronthaul/Aggregation

MPLS/Native IP

MPLS/Native IP

APPs

Network Service Orchestration Layer:

Network Services, NFV MANO, SDN Domain-Controllers, NMSs, etc.

NBIs

SBIs

Application controlled Network service orchestration

20

Architectural model for service orchestrator ETSI NFV Management and orchestration architecture

Application controlled Network service orchestration

21

Functional blocks of an ABNO architecture

SDN Architecture model