1

Optical Communication inOptical Communication inAccess NetworkAccess Network

K. T. WuK. T. WuDeanDean

College of EngineeringCollege of EngineeringNational University of KaohsiungNational University of Kaohsiung

OutlineOutline

•• IntroductionIntroduction•• Elements of Access NetworkElements of Access Network

–– CAU, Access Node, Access Transport, Edge CAU, Access Node, Access Transport, Edge NodeNode

•• Access TransportAccess Transport–– Optical CommunicationOptical Communication

•• Next Generation NetworkNext Generation Network•• ConclusionsConclusions

2

IntroductionIntroductionDrivers of the Access Network EvolutionDrivers of the Access Network Evolution

•• Unbundling of local loopUnbundling of local loop–– CLEC can provide new access technologiesCLEC can provide new access technologies

•• New TechnologiesNew Technologies–– xDSLxDSL–– Radio AccessRadio Access–– Fiber AccessFiber Access

•• IPIP--Based Network with QoSBased Network with QoS–– Rapid Growth in Data ServicesRapid Growth in Data Services–– VoIP ApplicationsVoIP Applications

•• MultiMulti--Services ConceptServices Concept–– High Bandwidth Data ServicesHigh Bandwidth Data Services–– PSTN/ISDNPSTN/ISDN

•• Cost IssueCost Issue

Elements of Access Network

Server Layer

BackboneAccessTransport

AccessNode

EdgeNode

Management Layer

AccessNode

CAU

CAU

CAU

CAU

CAU

CAU: Customer Access Unit

3

Technologies for Access NetworksTechnologies for Access Networks

Local Exchange, V5, Access Local Exchange, V5, Access Server, RouterServer, RouterEdge NodeEdge Node

SDH, DWDM, PON, FTTx, SDH, DWDM, PON, FTTx, EthernetEthernet

Access Access TransportTransport

LegacyLegacyMultiserviceMultiservice

Legacy DLC, Multiservice Legacy DLC, Multiservice PlatformPlatform

AccessAccessNodeNode

Narrow bandNarrow bandBroad bandBroad band

POTS, ISDN, T1/E1 Lease POTS, ISDN, T1/E1 Lease Line, DSL, EthernetLine, DSL, EthernetCAUCAU

TrendTrendInterfaces / TechnologiesInterfaces / Technologies

Integrated Access NodeDDN

E1 Network

G.703 64Kbit/s Network

ISDN

Internet

ATM Network

•Time Division Multiplex Technology

•Dynamic Time Slot Assignment

•Point-to-Point

•Tree / Hub

•Drop and Insert

•xDSL Technology

•ATM Technology

•Broadband Service Access Platform

• Single-ended Channel Bank

•Data Port Processor

•SNMP

E1 lease lineFractional E1NxE1POTSE&MRS232V.35 / V.36G.703 CO64ISDN (2B+D)Nx64kIDSLSHDSLADSLSTM-1IMAEthernet

TechnologyInterface V.35 / V.36

G.703

STM-1, IMA, DS3

ADSL,FE1,V.35/V.36

ISDN

E1

4

Broadband Digital Loop Carrier

Central Office (CO)

Switch

CO SideV5

Remote Side Payphone

PBX

2W

2W/4W

DSU/CSUE1/T1 Lease Line

POTS

2W/4W

Router

ManagementDatabase

Internet

Lease Line

Broadband Network

Ethernet ADSLRouter

SplitterADSL

•Access Transport

T1 / E1 OpticalPDH fiber terminal

SDH Interface

Multifunction Optical Network Unit

Narrowband Switched Network(Local Exchange)

Lease Line Network

ATM Broadband

Network

SDH ADM

SDH ADM

SDH

ADM SD

H A

DMSTM-N

SNCP RING

Central Office

ON

U (M

ultif

unct

ion)E1(V5.2)

E1(LL)

STM-1 or DS3 or E1(IMA)

E1(V5.2)

E1(LL)

STM-1 or DS3 or E1(IMA)

POTS

Pay-phone

ISDN BRA

2W / 4W

64 / 128 Kbit/s

E1, Nx64 Kbit/s

ADSL G.lit

POTS

ADSL G.dmt

POTS

LF

SATU-Rd

S

SATU-Ri

HTU-R

NTU

NT1

NMS Interface CIT

Network Interface

Service Interface

5

MSAN (Multi-Service Access Network)

MSAN

CO

MSAN

RTSTM-1, STM-4

•Point to Point•Star•Ring•Cascade

PONSTM-4STM-1

CO-RT

InterfaceTransport

10/100/1000 BaseT

IP

10/100/1000 BaseT

Softswitch

STM-4

STM-1SDH Trunk

E3/DS3

E1Lease Line

E3/DS3

STM-1ATM

CAS (Non V5)

E1 (V5.2)PSTN

InterfaceNetwork

Connection

STM-1

45M

34MOptical

VDSL

ADSL2/2+

ADSL

HDSL, SDSL or SHDLS

xDSL

45M (G.703)

34M (G.703)

2.048M (G.703)

N x 64 kDigital

Lease Line

ISDN PRI

ISDN BRI

Payphone

POTSPOTS &

ISDN

InterfaceSubscriber Services

CO-RT Transport

Subscriber Interface

Network Interface

PSTN

ATM SW

DDN Node

SDH

NGN Node

IP Node

Access TransportAccess Transport

•• SDH / SONET SDH / SONET –– Next GenerationNext Generation•• GbE / XGbE NetworkGbE / XGbE Network•• PONPON•• Others Others -- RPRRPR

6

Typical Metro TDM Transport NetworkAccess ADM

CO ADM

3/1 DCS

3/3 DCS

STM-16Ring

STM-16Ring

STM-16Ring

STM-16Ring STM-16

RingSTM-4Ring

STM-4Ring

STM-1Ring

CO: Central Office

ADM: Add-Drop Multiplexer

DCS: Digital Cross-Connect System

Inter-office Network

Access

Network

Access

Network

Access TransportNG SDH-Base Network Architecture

Metro AccessNG-SDHNetwork

Metro CWDM / NG-SDHNetwork

Transport CoreNetwork

EOS: Ethernet over SONET/SDH

STM-1/4 NGSDHADM with EOS

EOS MTU

Ethernet

Switch

IP DSLAM

AccessNetwork

OLT

ONU ONU

TDMSW/Mux

FTTx/EPON

NG SDH ADMwith EOS

STM-16 NG SDHADM with EOS

STM-1

STM-1

100/1000MEthernet

100/1000M Ethernet

10/100M

10/100M GbE

10M/100M

STM-1/4/16

xDSL xDSL

NG SDH ADMwith EOS

1 2 3

4 5 67 8 9

* 8 #

PSTNNetwork

100/1000MEthernet

Phase II

Phase I

10/100M

7

EOS Transport Model

IP

EthernetPHY

Enterprise Access Node Access Node

SONET BasedMetro Transport

NetworkEthernetPHY

SONETPHY

IWF

SONETPHY

EthernetPHY

IWF

IP

EthernetPHY

Enterprise

Internetworking Functions802.3x Flow ControlEthernet Status CollectionGFP/LAPS MappingVirtual Concatenation

EthernetMAC

EthernetMAC

EOS Transport Technology

Frame Mapping TechnologyGeneric Framing Procedure (GFP-F/T)Link Access Procedure – SDH (LAPS)

Dynamic Bandwidth Allocation TechnologyVirtual Concatenation (VCat)Link Capacity Adjustment Scheme (LCAS)

Ethernet

Optical Fiber/Optical Transport Network (WDM)

LAPS GFP-F/T

SONET/SDH with VCat+LCAS

DV

I

ESC

ON

FC

FIC

ON

Data SANs VideoIP

Low

er O

rder

SON

ET/S

DH

TDM

Frame MappingTechnology

Dynamic BandwidthAllocation

8

Link Capacity Adjustment Scheme (LCAS)Link Capacity Adjustment Scheme (LCAS)

•• A real time control mechanism to increase/decrease A real time control mechanism to increase/decrease capacity of a virtually concatenated group without capacity of a virtually concatenated group without incurring hits to active traffic.incurring hits to active traffic.

•• Rerouting of traffic due to current network conditions, Rerouting of traffic due to current network conditions, such as failures or maintenance proceduressuch as failures or maintenance procedures

•• Defined for all high and low order SONET and SDH Defined for all high and low order SONET and SDH payloadspayloads

IP Backbone Providers

ISPs

GbE Network Architecture

Multi-tenant Building

Multi-tenant Building

Multi-tenant Building

ASPs

Server Farm

GbE L2 Switch

GbE L2/3 Switch

Access GbE

SwitchAccess

GbE Switch

Core GbE Switch

Network

Multi-Tenant Unit (MTU) Building

LAN 1

LAN 2

LAN n

GbEGbE

GbE

GbE

9

Gb/10Gb Ethernet AdvantagesGb/10Gb Ethernet Advantages

•• Big cost advantage over SONET/SDH and ATMBig cost advantage over SONET/SDH and ATM•• Uses standard Ethernet frame format (no protocol Uses standard Ethernet frame format (no protocol

conversion)conversion)•• Full duplex pointFull duplex point--toto--point links with long reach to point links with long reach to

4040--70 km70 km•• Layer 2/3 switchesLayer 2/3 switches

–– VLAN capacity (802.1Q)VLAN capacity (802.1Q)–– Standard IP routing at layer 3 (e.g., OSPF, BGP)Standard IP routing at layer 3 (e.g., OSPF, BGP)–– Priority capability (aggregate flow QoS) provided by Priority capability (aggregate flow QoS) provided by

802.1p at layer 2 and DiffServ at layer 3802.1p at layer 2 and DiffServ at layer 3–– Traffic policing, shaping and monitoring at edgeTraffic policing, shaping and monitoring at edge

Gb/10Gb Ethernet DeficienciesGb/10Gb Ethernet Deficiencies•• Protection time ~ 1 sec >> 50 msec in SONET/SDHProtection time ~ 1 sec >> 50 msec in SONET/SDH•• QoSQoS

–– OverOver--provisioning needed to provide delay/jitter sensitive provisioning needed to provide delay/jitter sensitive apps.apps.

–– QoS provided for traffic aggregates, not individual flowQoS provided for traffic aggregates, not individual flow–– Providing QoS across network boundaries is difficultProviding QoS across network boundaries is difficult

•• PM and Fault management worse than SONET/SDHPM and Fault management worse than SONET/SDH–– Ethernet provides no overhead for performance monitoring, Ethernet provides no overhead for performance monitoring,

alarms, protection signaling, etc.alarms, protection signaling, etc.–– Except for 10GbE WAN PHY, these functions must be Except for 10GbE WAN PHY, these functions must be

performed at the management layerperformed at the management layer–– Proprietary solutions ( e.g., using the interframe gap) are Proprietary solutions ( e.g., using the interframe gap) are

being developedbeing developed•• Accommodation of Legacy TDM Services Accommodation of Legacy TDM Services use TDMoIP use TDMoIP

technologytechnology

10

PON Evolution

1998 20042003200220012000 Year

100K

1M

10M

100M

1G

Bit Rate(bps)

Carrier grading?

100M-Ether MC

GbE-MC

WDM-PON

G-PON600M B-PON

150M B-PON

STM PON

10M-Ether MC

ADSL

Developed

Developed

Developed IEEE 802.3 FSAN, ITU-T

FSAN, ITU-T

FSAN, ITU-T

LAN(SS)

PON StandardsPON Standards

•• ATMATM--based PONsbased PONs•• Early BPON Early BPON

products tested products tested and installed in and installed in limited quantities limited quantities by carriersby carriers

•• Supports Voice and Supports Voice and DataData

•• 622 Mbps 622 Mbps bandwidth ~70% bandwidth ~70% EfficiencyEfficiency

•• Adopted as ITU Adopted as ITU standard in 1999standard in 1999

EPON=EthernetEPON=Ethernet--based PONsbased PONsEmerging market, Emerging market, especially for especially for Metro EthernetMetro EthernetEfficiency (for Efficiency (for Voice and data Voice and data services) services) --~49%~49%1Gbps bandwidth1Gbps bandwidthIEEE acceptance IEEE acceptance expected only in expected only in 20042004

•• GPON=Gigabit PONGPON=Gigabit PON•• Evolution in FSAN Evolution in FSAN

Committee for Committee for Voice and Data in Voice and Data in their native formattheir native format

•• Efficiency (for Efficiency (for voice and data voice and data services) services) --~93%~93%

•• 2.5Gbps+ of 2.5Gbps+ of bandwidth at 93% bandwidth at 93% EfficiencyEfficiency

•• ITU ratification in ITU ratification in 20032003

BPON G.983

EPONGPONG.984

1995 Today

- PON Evolution Timeline -

11

EPON vs. APON, GPONEPON vs. APON, GPON

20 km20 km20 km20 kmType1 <= 10 Type1 <= 10 kmkmType2 <= 20 Type2 <= 20 kmkm

Max ReachMax Reach

Class A, B, CClass A, B, CClass A, BClass A, BType1, Type2Type1, Type2ODN TypeODN Type

1010--12121010--10101010--1212BERBER

Scramble NRZScramble NRZScramble NRZScramble NRZ8B/10B8B/10BLine CodingLine Coding

TDMATDMATDMATDMATDMATDMAUS MAC schemeUS MAC scheme

MiddleMiddleLargeLargeSmallSmallProtocol overhead for Protocol overhead for IPIP

Ethernet/ATM/TDMEthernet/ATM/TDMATMATMEthernetEthernetBasic protocolBasic protocol

Up to 2.488 GbpsUp to 2.488 Gbps155/622155/622622/1244 Mbps 622/1244 Mbps (Amendment)(Amendment)

1G1GSpeedSpeed

SPSPSPSPVendorsVendorsStandard driven byStandard driven by

2003.11 2003.11 (G.GPON.GTC)(G.GPON.GTC)

199819982004.072004.07Standardization Standardization timelinetimeline

ITUITU--T SG15 (FSAN)T SG15 (FSAN)ITUITU--T (FSAN)T (FSAN)IEEEIEEEStandard bodyStandard body

GPONGPONAPONAPONEPONEPON

GPON TC Layer Options

Layer 1 PON-PHY

Layer 2

ATM Cell Generic frameEthernet frame

G.983 base G.707 base IEEE 802.3 base

AAL1/AAL2 AAL5

Layer 3

Layer 4

Layer 5 or more

T1/E1 TDM

POTS

Ethernet

IP

TCP+UDP etc.

Data

VideoT1/E1 TDM

POTS

Ethernet

IP

TCP+UDP etc.

Data

VideoT1/E1 TDM

POTS

IP

TCP+UDP etc.

Data

Video

Now being discuess in PWE3 WG in TETF

ATM frame base Generic frame base Ethernet frame base

•Comparative analysis will be made by the FSAN members

•One of the best solutions will be proposed to ITU-T from the members in FSAN

12

Interworking between TDM and IP Networks

Internet

TDM Service POP

Packetize T1 or E1 circuit over IP

ISP Services e.g., Web hosting

IXC•ATM•Frame Relay

Voice CLEC•PSTN (Class 5)•Centrex (Class 5)•Clearinghouse (VoIP)

TDM Service POP

IP routing onlyILEC Network

Unbundled Local Loops

Multi-Tenant Unit

Building #1

Building #2

Building #3

T1, E1

n x T1, n x E1, MLPPP, MLFRE1 or E3,

T1 or T3 Lines

T3, E3

T3, E3

TDMoIP / CESoPTDMoIP / CESoP

•• Encapsulate TDM Signal (T1, E1, T3, E3) in IP Encapsulate TDM Signal (T1, E1, T3, E3) in IP packetspackets

•• Transparent service deliveryTransparent service delivery–– In Band Signaling id preserved andIn Band Signaling id preserved and--toto--endend

•• EndEnd--toto--End Delay in minimizedEnd Delay in minimized–– Low latencyLow latency

•• Tributary clock recovery id difficultTributary clock recovery id difficult–– Adaptive clock methodAdaptive clock method–– Differential clocking method (similar to SRTS in AAL1)Differential clocking method (similar to SRTS in AAL1)

13

Edge Node and Local ExchangeEdge Node and Local Exchange

•• Local Exchange may be replaced byLocal Exchange may be replaced by–– Multiservice access nodesMultiservice access nodes–– Media gatewayMedia gateway–– Telephony serverTelephony server

•• Access ServersAccess Servers–– Narrowband Access ServerNarrowband Access Server–– Broadband Access ServerBroadband Access Server

•• Voice GatewayVoice Gateway–– VoIP gateway, H.323 / SIPVoIP gateway, H.323 / SIP–– VoDSL gateway, (AAL2)VoDSL gateway, (AAL2)

•• RoutersRouters

Next Generation NetworkNext Generation NetworkIP-Based and All IP in the Future

Server Layer

BackboneAccessTransport

AccessNode

EdgeNode

AccessNode

CAU

CAU

CAU

CAU

CAU

IP Network Coverage

Management Layer

1

23

14

Next Generation Network (NGN)Next Generation Network (NGN)

•• Access Transport and Backbone Network Access Transport and Backbone Network IP NetworkIP Network

•• Server Layer and Edge Node Server Layer and Edge Node Sever, Sever, Controller, Internetwork GatewayController, Internetwork Gateway

•• Access Node Access Node GatewayGateway

•• CAU CAU Intelligent Access UnitIntelligent Access Unit

Technologies for Access NetworksTechnologies for Access Networks

Server, Controller, Server, Controller, Internetwork GatewayInternetwork Gateway

Local Exchange, Local Exchange, V5, Access V5, Access Server, RouterServer, Router

Edge NodeEdge Node

IPIP--Based NetworkBased NetworkSDH, DWDM, SDH, DWDM, PON, FTTx, PON, FTTx, EthernetEthernet

Access Access TransportTransport

GatewayGatewayLegacyLegacy

MultiservicMultiservicee

Legacy DLC, Legacy DLC, Multiservice Multiservice PlatformPlatform

AccessAccessNodeNode

IntelligentIntelligentNarrow bandNarrow band

Broad Broad bandband

POTS, ISDN, POTS, ISDN, T1/E1 Lease T1/E1 Lease Line, DSL, Line, DSL, EthernetEthernet

CAUCAU

NGNNGNTrendTrendInterfaces / Interfaces / TechnologiesTechnologies

15

NGN Applications (VoIP-SIP Based)

Managed IP Network

Media Server

ApplicationServer

Media GatewayController

Network Management &

Service Management

SignalingGateway

TrunkGateway

AccessGateway

Residential Gateway

Session InitiationProtocol Server

PSTN

ServiceControlPoint

BillingCenter

NetworkManagement

Center

IP Soft phone

IP Videophone

IP Hardphone

SIP SS7

E1

MGCP/H.248

SIP

LANxDSL

3GPP Release 5 IP Multimedia Network

HSS/HLR

Node B

Node B

SGSNlub

lublur

lu-PS

Gr

RNC

RNC

Cx

MRF

Mr

GGSN

Gi

Gn

SS7

PSTN

Internet

SS7

MGW

T-SGW

Gi

Gi

Mc

PCM

Mg

R-SGW

Media Gateway Control Function (MGCF)

CAll State Control Function (CSCF)

CSCF

16

ConclusionsConclusions

•• Access Node Interfaces vary from NB to BB, to Multi Access Node Interfaces vary from NB to BB, to Multi servicesservices

•• Access Transport can be SONET/SDH, Gb/XGb Ethernet, Access Transport can be SONET/SDH, Gb/XGb Ethernet, PON, RPR PON, RPR Optical Communication BasedOptical Communication Based

•• An Evolution to NGN Driver is An Evolution to NGN Driver is ““IPIP””–– Near tem convergence: TDMoIPNear tem convergence: TDMoIP–– Long term convergence: All IPLong term convergence: All IP

•• Telecom and Data Com become IP ComTelecom and Data Com become IP Com