5g: an ip engineer perspective - nanog...gnb internet ip core backhaul ip udp gtp-u ip ip sctp ng-ap...
TRANSCRIPT
1
5G: an IP Engineer Perspective
Igor GiangrossiPrincipal Consulting Engineer | IP/Optical Networks
NANOG 75
2 NANOG 75
From analog voice to high speed InternetA Brief History of Mobile Networks
1980 1990 2000 2010 2020
1G
Analog Voice
Nokia Cityman Nokia 3210
No Data
2G
Digital Voice
100s of kbps
3G
Mobile Data
10s of Mbps
iPhone 3G
4G
Mobile Broadband
100s of Mbps
5G
iPhone X
?
3 Nokia Internal
ITU-R IMT-2020 performance goalsWhat Is 5G?
Peak Data Rate (Gbps)
User Experienced Data Rate (Mbps)
Spectrum Efficiency
Mobility (Km/h)
Latency (ms)
Connection Density (devices/km2)
Energy Efficiency
Area Traffic Capacity (Mbps/m2)
20
100
3x
500
1
106
4G5G
100x
10
1
0.1
10x 1x
105
10
350
1x
10
1
Peak Data Rate
User Experienced Data Rate
Spectrum Efficiency
Mobility
Latency
Connection Density
Energy Efficiency
Area Traffic Capacity
High
Importance
Medium
Low
Massive MachineType Communications
Enhanced MobileBroadband
Ultra Reliable And Low Latency Communications
Source: ITU-R M.2038.0
4 NANOG 75
Main nodes and functionsRecap: 4G/LTE Evolved Packet Core
MME: Mobility Management EntitySGW: Serving GatewayPGW: PDN GatewayeNB: eNodeB (Radio)
SGW
MME
InterneteNB PGW
IP Core
S11
S5
S1-MME
S1-U
Mobility and Session ManagementInterface to Subscriber Database
Mobility Anchor PointSession ManagementPacket Forwarding
IP Anchor PointSession ManagementPacket ForwardingInterface to Policy, Charging, etc.
SGi
5 NANOG 75
Combined control and user plane over IPRecap: 4G/LTE Architecture and Traffic Flows
SGW
eNB MME
InterneteNB PGW
IP Core
Backhaul
IP
UDP
GTP-U
IP
IP
SCTP
S1-AP
User Plane (S1-U)
Control Plane (S1-MME)
X2
IP
MME: Mobility Management EntitySGW: Serving GatewayPGW: PDN GatewayeNB: eNodeB (Radio)
GPS/SyncE/1588v2/NTP
IP
UDP
GTP-U
IP
S11
IP
UDP
GTP-C
S5
6 NANOG 75
Main nodes and functions5G Architecture: Native Control and User Plane Separation
gNB UPF UPF
Internet
Internet
SMFAMF
N3
N2N4 N4
N6N9
N6
SBA Bus
NAMF NSMF
Distributed User Plane
Centralized User Plane
AMF: Access and Mobility Management FunctionSMF: Session Management FunctionUPF: User Plane FunctionSBA: Service Based ArchitecturegNB: gNodeB (Radio)
User Plane
Control Plane
Session ManagementMobility Management
Packet Forwarding
7 NANOG 75
Same backhaul protocol stack with REST control plane5G Architecture and Traffic Flows
UPF
gNB AMF
InternetgNB
IP Core
Backhaul
IP
UDP
GTP-U
IP
IP
SCTP
NG-AP
User Plane (N3)
Control Plane (N2)
Xn
IP
GPS/1588v2
N6
SBA Bus
NAMF NSMF
N4
IP
TCP
HTTP/2
REST/JSON
IP
UDP
PFCP
SMF
AMF: Access and Mobility Management FunctionSMF: Session Management FunctionUPF: User Plane FunctionSBA: Service Based ArchitecturegNB: gNodeB (Radio)
8 NANOG 75
Requires a service-aware backhaul network5G Network Slicing for “Network as a Service”
gNB
AMF
N3
N2
SBA Bus
NAMF
NSSF
NNSSF
TE-enabledBackhaul
NSSF: Network Slice Selection Function
9 NANOG 75
CRAN architecture introduces CPRI for the Fronthaul networkRAN Densification: Searching for Better Radio Coordination
EPC: Evolved Packet CoreRRH: Remote Radio HeadBBU: Baseband Unit
Centralized RAN
S/PGW
RRH RRH RRH
BBU Pool
Backhaul
Fronthaul
eNBs
Time Division Multiplexing
IQData Ve
ndor
Spec
ific
Ethe
rnet
HD
LC
L1 In
-ban
dPr
otoc
ol
User PlaneControl &
ManagementSync
CPRI: Common Public Radio Interface
Requires DedicatedFiber (xWDM)
Ultra low delay variation (16ns)
P2P constant bitrate stream
10 NANOG 75
Targeting a 10X increase in throughput5G New Radio Main Technology Innovations
1GHz 6GHz 24GHz
mmWave
New Spectrum Options
Larger Radio Channels
Up to 400MHz
Massive MIMO
11 NANOG 75
CPRI bandwidth explosion with massive MIMOCurrent CRAN Architecture Unfit for 5G Deployments
1Gbps
10Gbps
100Gbps
1000Gbps
1Tx20MHz
4Tx20MHz
64Tx20MHz
64Tx100MHz
14
64
320
*Approximate values
12 NANOG 75
Transport related standards bodies5G Standards Development Initiatives
Additional initiatives exist to address other areas of 5G standards (O-RAN, Small Cell Forum, etc.)
Main 5G standards (release 15):- Overall architecture- Radio- Core
Ethernet forwarding standards:- 802.1CM – Time Sensitive
Networks- NGFI – Next Generation
Fronthaul Interface• 1914.1 – Packet Based
Fronthaul• 1914.3 – Radio over
Ethernet
Fronthaul protocols:- CPRI v7.0 (2015)- eCPRI v1.2 (2018)
Fronthaul transport services specification:- MEF 22.3- MEF 22.3.1
13 NANOG 75
RAN protocol stack split optionsAddressing the Fronthaul Bandwidth Challenges
PDCP
Option 7
RLC
MAC
PHY
RF
RRCIP
Option 6
Option 5
Option 4
Option 3
Option 2
Option 1
Layer 1
Layer 2
Max.Latency
RequiredBandwidth
CPRIOption 8
14 NANOG 75
RAN protocol stack split optionsAddressing the Fronthaul Bandwidth Challenges
PDCP
Option 7
RLC
MAC
PHY
RF
RRCIP
Option 6
Option 5
Option 4
Option 3
Option 2
Option 1
Layer 1
Layer 2
Max.Latency
RequiredBandwidth
HighLayer
LowLayer
Option 8
15 NANOG 75
Cloud RAN with packet-based transport5G NR Introduces a New RAN Architecture
EPC/5GC
RU RU RU
DU
Backhaul
Fronthaul
CU
Midhaul
gNB
F1
Xn
NG/S1 NG/S1
CU: Centralized UnitDU: Distributed UnitRU: Radio Unit
DU DU
F1F1
RU RU RU
DU
CU
gNB
F1
DU DU
F1F1
Low Layer Split(Option 7-2a)
High Layer Split(Option 2)
16 NANOG 75
Similar to current backhaul protocol stackNew Midhaul Interfaces: E1 and F1
E1
F1-U F1-C
N3 N2
gNB
IP
UDP
GTP-U
User Plane
IP
SCTP
F1-AP
IP
SCTP
E1-AP
RU
DU
CU-UP CU-CP
17 NANOG 75
Designed for packet-based networkseCPRI: Fronthaul Transport over Ethernet
UserData
Real-TimeControl
OthereCPRI
ServicesSynchronization
ConnectionOAMC&M
eCPRI Protocol Header
eCPRI Services
UDP (Optional)
SyncEPTP SSH,SNMP, etc
ICMP
UDP, TCP,etc.
IPIP (Optional)
Ethernet (Etype:AEFE) VLAN+PCP MACSec EthernetOAM
18 NANOG 75
Savings of 10x compared to CPRIeCPRI Fronthaul Bandwidth Estimations
236Gbps
236Gbps
Down Up
Option 7-2(Uplink)
User/Up
Control/Up
20Gbps
<10Gbps
User/Down
Control/Down
Basic Assumptions: 100MHz8x4 MIMO (w/ 2 streams per uplink layer)64 AntennasTTI: 1msModulation: 256QAM*3Gbps downlink from MAC layer*1.5Gbps uplink to MAC layer
CPRIOption 7-2(Downlink)
eCPRI
20Gbps
<10Gbps
Drives 25GE interfaces
19 NANOG 75
Direct implication on inter-node distancesIEEE1914.1 & eCPRI Recommended One-Way Latency
Fiber Latency=5!s/km
RU
Backhaul Fronthaul
DU5G Core
Midhaul
CU
UPF
>10ms
(50!s for URLLC)
1ms 100!s
>2000km
(10km for URLLC)
200km 20km
20 NANOG 75
QoS for mixing Fronthaul with other traffic flowsIEEE 802.1CM – Time Sensitive Networks
4
3
1
Fronthaul 2
Other
4 3 12Egress port:
Profile A: Strict PriorityFronthaul: High PriorityOther: Low Priority
134 2Egress port: 1
FramePreemption
Profile B: Frame Preemption (<10GE only)Fronthaul: Express TrafficOther: Preemptable Traffic
Supported Today
Requires MAC Change(mated boxes on a link)
Ingress traffic
21
Timing architecture driven by RAN features and TE budgeteCPRI Fronthaul Depends on External Synchronization
NANOG 75
RUDU
T-GM T-TSC
GPS
Tight TE Budget Relaxed TE Budget
RU
DU
Core
T-BC T-TSC
T-GM CU
T-BC
T-TSC
Fronthaul Backhaul Midhaul Fronthaul
G.8275.1 + SyncEG.8275.1 + SyncE
Category Max TE (ns) RAN features
A+ ±20 (relative) MIMO, Tx-diversity
A ±70 (relative) Intra-band CA
B ±200 (relative) Inter-band CA
C ±1100 (absolute)* Basic TDD, LTE CoMP/eICIC
*Note: Time error figures are between any two given RUs in the network, except for Category C which is an absolute value from the timing source (T-GM).
Class Max TE (ns)
A ±50
B ±20
C ±10
Router TE classes(G.8273.2) Radio Timing Requirements
RU
T-TSCTE
(relative)
RU
T-TSCTE
(relative)
22 NANOG 75
Radio and IP/Transport planning must be done togetherSummary: No One-Size Fits-All Solution
5G Core RU
Backhaul(>10ms)
Fronthaul(100us)
Midhaul(1ms)
DUCU
5G Core DU+RUCU
5G Core RUCU+DU
5G Core CU+DU+RU
Backhaul(>10ms)
Backhaul(>10ms)
Midhaul(1ms)
Fronthaul(100us)
Backhaul(>10ms)
DAT
A CE
NTE
R/N
FVI
