LTE Backhaul: New Architectures for All-IP

Thursday, June 11, 2009

Moderated byPatrick Donegan

Senior Analyst

Virtual Tradeshow

Our Panelists

• Ran Avital, VP Marketing, Ceragon

• Ralph Santitoro,Director of Carrier Ethernet Market Development, Fujitsu Network Communications

• Eitan Schwartz, VP Pseudowire & Ethernet Access, RAD Data Communications

IP

Voice Core (MSC)

3G W-CDMA Architecture

4G LTE Architecture

Data Core (SGSN/GGSN)

EvolvedPacket CoreS1 interface

X2 interface

Iub interface

Iu PS interface

Iu CS interface

Iub interface

S1 interface

ATM/IP

ATM/IP

IP

“LTE is the first genuinely all-IPwireless standard. It requires IP/MPLS routing in every node in the network, including throughout the backhaul.”

The statement below should be considered as a debating point – not as an opinion of Heavy Reading.

Technology Options For Connection-Oriented Ethernet (COE)Significant Differences Among Number of Layers to Manage

IP/MPLS

(3) Data Plane Layers1) Ethernet2) Pseudowire (PW)3) LSP

VLAN TagVLAN TagSwitchingSwitching

Routed Non-Routed

StaticPW/MPLS T-MPLS

(1) Data Plane Layer• Ethernet

MPLS-TP PBB-TEPBB-TE

PW

MPLS-TP LSP

PWEth Eth

BFD, Protection ProtocolBFD, VCCV

802.1ag, 802.3ah, Y.1731

MPLS-TP-based COEIP/MPLS-Based COE

PW

MPLS LSP

Eth Eth

BFD, RSVP-TE/LDP, FRR

802.1ag, 802.3ah, Y.1731

IS-IS, OSPF, BGP, IP addressing, BFD

PW

T-LDP/BFD, VCCV

S-VLAN or PBB-TE TunnelS-VLAN or PBB-TE Tunnel

EthEth EthEth

G.8031, 802.1ag, 802.3ah, Y.1731G.8031, 802.1ag, 802.3ah, Y.1731

Ethernet-based COEEthernet-based COE

Ethernet

(3) Data Plane Layers1) Ethernet2) Pseudowire (PW)3) LSP

(1) Control Plane Layer• IP

Ethernet+PW+LSPEthernet+PW+LSP

Ethernet-based COE simplifies OAM&P Only 1 Layer to manage: Ethernet

“The X2 interface between eNode Bs will only support a little

bit of cell handover traffic initially – it probably won’t be used

for anything more than that.”

The statement below should be considered as a debating point – not as an opinion of Heavy Reading.

Proposed LTE Architecture• Example 3

• Backhaul for LTE• EVPL for S1 interface• E-LAN for X2 interface

Carrier Ethernet Aggregation Network

UNI UNIRAN BS RAN NC

Carrier Ethernet Access Network

ENNI

RAN BS

UNI

Carrier Ethernet Access Network

ENNI

RAN BS

EVPL 1EVPL 2EVPL 3EVPLAN

“Most integrated fixed and wireless carriers will implement an L3-based backhaul for LTE because they already have the L3

engineering skill-sets”

“Most pure-play wireless operators and wholesale backhaul providers will implement

an L2 backhaul network – because they don’t.”

The statements below should be considered as a debating point – not as an opinion of Heavy Reading.

• Wholesale backhaul providers typically prefer L2: • Simpler to provision• Scalable BW “pipes” for unpredictable needs• Strong Ethernet OAM mechanisms offer SLA• Sub 50ms failover with 802.3ad and G.8032• Pseudowire helps support 2G/3G services, in addition to LTE• Powerful diagnostic tools

• “Pure-Play” wireless operators typically prefer L2:• Simple / automatic provisioning• Ethernet circuit validation, PM, fault detection and analysis• Traffic engineering oversubscribe link bandwidth

• Integrated carriers may prefer L3 (skill sets)• Mesh, alternate routing, but less developed OAM

L2/L3 Backhaul Challenges

Audience Poll “As LTE is an all-IP network, it will require

routing at every node in the network, including all the backhaul nodes.”

To what extent do you agree or disagree?

• Strongly agree• Somewhat agree• Neither agree nor disagree• Somewhat disagree• Strongly disagree

Multi-Generation Backhaul“Transporting legacy 2G and 3G cellular traffic

over the existing TDM network while LTE is transported over a separate

packet backhaul is optimal.”

“Better that than trying to emulate2G and 3G over a single packet backhaul for all

generations of cellular traffic.”

The statements below should be considered as a debating point – not as an opinion of Heavy Reading.

Evolution From Sonet To Packet-Based Ethernet MBH

FMO Step 1: Add COE over Sonet

to increase bandwidth efficiency

PMO: Sonet

Sonet

FMO Step 2: Begin Migration to EoF

packet network. Existing services unaffected

DS1s Ethernet

Packet-optical networking platform with COE facilitates MBH network migration of multi-generation 2G/3G/LTE services

EoS

MSPP

TDM

Sonet

DS1s Ethernet

COETDM

Sonet

DS1s Ethernet

COETDM

EoF

Packet Optical

Networking

Packet Optical

Networking

2G/3G 2G/3G LTE 2G/3G 3G/LTE

“There is a big differencebetween backhaul equipment

being Ethernet-ready and being LTE-ready.”

The statement below should be considered as a debating point – not as an opinion of Heavy Reading.

LTE Backhaul Requirements (…and the radio perspective)

14

Requirements DetailsHigh Capacities 50-200 Mbit/s per sitePeak rate & average 173 Mbit/s vs. 35 Mbit/sLow latency <10msecHandover interface (X2) E-LAN for eNBs CommunicationEnhanced services Service-aware networksDeployment paradigms Hotspot the size of a city/rural BBMigration strategies TDM Ethernet 2G3GLTESynchronization E1/T1 for legacy. 1588V2 & SyncEConvergence True multiplay operators

“The differences in synchronizationrequirements between

3G and LTE are academic.”

“This is because most operators are going to leave a T1/E1 at the cell site for packet backhaul synchronization

rather than adopt a new standard, none of which is mature yet.”

The statements below should be considered as a debating point – not as an opinion of Heavy Reading.

Multi-Generation Backhaul with Multiple Synchronization Options

TDM

ATM IMA

TDM

ATM

2G BSC

3G RNC

ETH

SHDSL

ATM IMA

IP-DSLAM

Physical-layer SyncE1/T1 TDM link

Sync-Ethernet (G.8262)

NTR – DSL/GPON

TDM link

Adaptive /IEEE 1588-2008

Sync-E

NTR

FE/GbE

IP Node B

ETH

S1 (ETH)

aGW

PacketSwitchedNetwork

TDM/SONETNetwork

Node B

eNode B

E1/T1

E1/T1

Packet-based SyncAdaptive

1588-2008

NTP

Sync-E

“LTE’s All-IP architecture will leave the backhaul open to security attacks on a far greater scale than ever before.”

“A lot of operators haven’t thought the implications through nearly well enough.”

The statements below should be considered as a debating point – not as an opinion of Heavy Reading.

Security With Connection-Oriented Ethernet

• COE uses few protocols. IP & MPLS require many• The more protocols used, MBH network is more susceptible to attacks

• Management VLANs isolated from user traffic• Similar to DCC isolation from user traffic in Sonet networks

• COE has many security advantages over bridged solutions• COE disables MAC address learning / flooding

• MAC address spoofing cannot occur

• MAC table overflow DOS attacks cannot occur

• COE disables vulnerable Layer 2 control protocols (L2CPs)

• Protocol-based DOS attacks cannot occur

COE is immune to IP-based attacks & popular L2-based attacks

“With any new technology, it’s always the OAM that get’s left till last, and

IP/Ethernet backhaul is no different.”

“The OAM standards are not mature, particularly as regards integrationwith legacy TDM OAM systems.”

The statements below should be considered as a debating point – not as an opinion of Heavy Reading.

Sample Scenario:Carrier Ethernet Services in Mobile Backhaul #1

Ring site#3

Fiber site

RNC

Ethernet Microwave

Ring site#2

WirelessCarrier Ethernet

Ring

Tail site #1

Tail site #2

Tail site #3

Ring site#1

Packet or TDM based fiber aggregation

network or leased lines

End-to-end connectivity per service is verified

using periodic 802.1ag CCM messages between

service end points.

End-to-end connectivity per service is verified

using periodic 802.1ag CCM messages between

service end points.

AA

BB

CC

Ethernet Microwave

Ethernet Microwave

Ethernet Microwave

Ethernet Microwave

Ethernet Microwave

Ethernet Microwave

Ring site#3

Fiber site

RNC

Ring site#2

Wireless

Carrier EthernetRing

Tail site #1

Tail site #2

Tail site #3

Ring site#1

Packet or TDM based fiber aggregation

network or leased lines

AA

BB

CC

Sample Scenario:Carrier Ethernet Services in Mobile Backhaul #2

Ethernet Microwave

Ethernet Microwave

Ethernet Microwave

Ethernet Microwave

Ethernet Microwave

Ethernet Microwave

Ethernet Microwave

Ring site#3

Fiber site

RNC

Ring site#2

WirelessCarrier Ethernet

Ring

Tail site #1

Tail site #2

Tail site #3

Ring site#1

Packet or TDM based fiber aggregation

network or leased lines

No alternate path available for Service A.

Service connectivity failure is reported by service end

points.

No alternate path available for Service A.

Service connectivity failure is reported by service end

points.

AA

BB

CC

AA

Service B is restored using alternate path

over the ring.No service connectivity

alarm is generated.

Service B is restored using alternate path

over the ring.No service connectivity

alarm is generated.Services B & C now share the

same radio link resulting in higher traffic load.

QoS is used to provide service differentiation for high priority

and delay sensitive traffic.

Services B & C now share the same radio link resulting in

higher traffic load.QoS is used to provide service differentiation for high priority

and delay sensitive traffic.

Sample Scenario:Carrier Ethernet Services in Mobile Backhaul #3

Ethernet Microwave

Ethernet Microwave

Ethernet Microwave

Ethernet Microwave

Ethernet Microwave

Ethernet Microwave

Ethernet Microwave

“The vast majority of wholesale backhaul providers and wireless operatorswill design their packet backhaul for 2G and 3G as well as LTE.”

“And since 90% of wireless traffic will be 2G and 3G through 2014,

the LTE design requirements aren’t critical in today’s design assumptions.”

The statements below should be considered as a debating point – not as an opinion of Heavy Reading.

Transport Provider

E2E SLA Monitoring and Diagnostics

EthernetAccess Ring

(50ms)4G G/W

GigEGigE

MSC

CT3/OC3

MobileOperator B

FixedWirelessMSC

CT3/OC3

4G G/W

MobileOperator A

GigEGigE

Test Equip.

Mobile Operator E2E T1 & Ethernet Diagnostics

Test Equip.

Data VLANs – Carry BH traffic, OAM and test data. Mgt VLAN – Management and SLA statistics

NMS Portal

WholesaleCarrier Ethernet

MPLS

T1/E1

ETH

4G eNB

2G/3G

T1/E1

ETH

4G eNB

2G/3G

T1/E1

ETH

4G eNB

2G/3G

2G/3G/4G Backhaul Services over Ethernet/IP/MPLS