passive optical networks - materias.fi.uba.armaterias.fi.uba.ar/7543/2011-01/download/pon_e1... ·...

Passive Optical Networks

Authors:Fabio Neri

Jorge M. Finochietto

Tutorial

Passiv

e O

pti

cal N

etw

ork

sContents

• Introduction– Motivation– Optical Access Networks– Passive Optical Networks (PON)

• TDM-PON– Physical Layer and Devices– Traffic Distribution/Scheduling– Power Budget– Standards

• APON/BPON• EPON• GPON

• WDM-PONs– Proposed solutions


Introduction

Passiv

e O

pti

cal N

etw

ork

sThe Broadband Connected Household

Energy

monitoring

Video- Conference

Alarm

Lock

Laundry

booking

Real Estate services

Ethernet

HDTVHome station

Set Top Box

100 Mb/s

O/E IP

TV

Computers

Telephone

InteractiveGaming

2x20 Mb/s

TV-channels +VoD services

TriplePlay

10-50 Mb/s

2x5 Mb/s

DVR

Passiv

e O

pti

cal N

etw

ork

s

Technologies for access network:• Plain Old Telephone Service (POTS)• Asymmetric Digital Subscriber Loop (ADSL)• Cable-modems using Cable-TV (CATV)

infrastructures • Power Line Communication – PLC• Wireless access technologies

– Local Multipoint Distribution Service (LMDS)– WiFi/WiMax– Cellular networks

• Optical access networks

Access Network

Passiv

e O

pti

cal N

etw

ork

sxDSL Solutions

• Largely deployed nowadays– Use of existing copper lines– Smooth migration/upgrade of current network

• Bandwidth and reach are limited!

1 Km 2 Km 3 Km 4 Km 5 Km 6 KmLength, Km

8

24

ADSL

ADSL2+

VDSL

52

Data Rate, Mbps

ADSL2

12

Shannon’s information theorem…(S/N-limited, here: crosstalk)

Source: Ericsson

http://www.wap.org/journal/cotour/dslracks.jpg

Passiv

e O

pti

cal N

etw

ork

sADSL: User Devices

• Splitter– separates data from voice signals

• Modem– (de)modudulates signals at proper frequencies (e.g.,in ADSL, from 25 KHz in upstream, and from 240 KHz in downstream)

Voice Data

Passiv

e O

pti

cal N

etw

ork

s

• CATV infrastructures are also called Hybrid Fiber Coax (HFC)

• They offer a unidirectional high speed downstream channel

HFC Access Network

Headend

Remote nodefiber

coax

amplifiers

tap

Passiv

e O

pti

cal N

etw

ork

sFiber To The X (FTTx)

FTTC : Fiber To The Curb

FTTCab : Fiber To The Cabinet

FTTH : Fiber To The Home

FTTB : Fiber To The Building

“Soon”

Service Node

ONU

FTTH

FTTB

FTTC

FTTCab

Optical Fiber

PON xDSL

OLT

ONU NT

NT

Internet

Leased Line

Frame/Cell

Relay

Telephone

Interactive

Video

Twisted Pair

ONT

ONT

$$$

“Soon”

“Later”

“Later”

$

$$

$-$$

Passiv

e O

pti

cal N

etw

ork

sOptical Access Networks

• Low Attenuation, large distances

• Low power consumption• Large Bandwidth, many

broadband users

• Requires new fiber installation

• Outside plant costs are important!!

Passiv

e O

pti

cal N

etw

ork


• Point-to-Point links– Simple, standardized and mature technology– N fibers lines– 2N transcievers

Passiv

e O

pti

cal N

etw

ork


• Active Optical Network– Simple, standardized and mature technology– 1 fiber line– Curb Switch → power in the field– 2N+2 transcievers

Passiv

e O

pti

cal N

etw

ork


• Passive Optical Network (PON)– Simple, under standardization technology– 1 fiber line– N+1 transcievers– passive devices (splitters)

Passiv

e O

pti

cal N

etw

ork

s

Passive Devices

Downst

ream

Tra

ffic

Upstream Traffic

ODN

PON Overview

OLT: Optical Line TerminatorONU: Optical Network UnitODN: Optical Distribution Network

Passiv

e O

pti

cal N

etw

ork

sTime vs. Spectrum Sharing

• Downstream → point-to-multipoint network– The OLT manages the whole bandwidth

• Upstream → multipoint-to-point network– ONUs transmit only towards the OLT– ONUs cannot detect other ONUs transmissions– Data transmitted by ONUs may collide

Need of a channel separation mechanism to fairly share bandwidth

resources

TDMATime Division Multiple

Access

WDMAWavelength Division Multiple

Access

Passiv

e O

pti

cal N

etw

ork

sPON Evolution

• TDM-PONs– Standarized– Use few wavelengths (typically 2 or 3) – Low cost and mature devices (splitters, lasers, etc.)– Limited power budget

• Maximum distances ≤ 20km, Split ratios ≤ 64– Traffic distribution

• Broadcast scheme in downstream • TDMA techniques in upstream

– Examples: APON/BPON, EPON & GPON• WDM-PONs

– Proposed in literature and/or demonstrated– Introduce WDM techniques and devices (AWG)– Long-reach and bandwidth– Examples: CPON, LARNET, RITENET, Success-DWA…

Passiv

e O

pti

cal N

etw

ork

sContents






TDM-PONs

Passiv

e O

pti

cal N

etw

ork

s

OLT

PON Physical Layer

PassiveSplitter

ONU

ONU

ONUODN

• Passive splitter/combiner(s)• Two separated channels

– Downstream (OLT → ONUs)

– Upstream (ONUs → OLT)

• A 3rd channel can be used for broadcasting video

Passiv

e O

pti

cal N

etw

ork

sOptical Fiber: Attenuation

• Single Mode Fiber (SMF) to achieve large distances– ITU G.652 SMF (STD)

• “water peak” attenuation renders the 1360nm–1480nm spectrum unusable for data transmission

– ITU G652c/d SMF (ZWP)• “zero-water peak”

800 900 1000 1100 1200 1300 1400 1500 1600 1700

0.5

1.0

1.5

2.0

2.5

3.0

FirstWindow Second

Window

ThirdWindow

ATTEN

UA

TIO

N (

dB

/km

)

WAVELENGTH (nm)

1310nm

1550nm

850nm

STD SMF

ZWP SMF

Passiv

e O

pti

cal N

etw

ork

sOptical Fiber: Chromatic Dispersion

• Causes signal pulse broadening

Passiv

e O

pti

cal N

etw

ork

sWavelengths

Low loss (∼0.3 dB/km)Chromatic dispersion (∼10-17 ps/nm.km)Optically amplified by EDFAs (1550nm)

1490nm1550nm

Low loss (∼0.5 dB/km)Zero chromatic dispersion

1310nm

Passiv

e O

pti

cal N

etw

ork

sLasers Diodes (LD)

• Fabry-Perot (FP)– Cheap– Noisy

• Sensitive to chromatic dispersion

– Used on 1310 nm

• Distributed Feedback (DFB)– More expensive– Narrow spectral width

• Less sensitive to chromatic dispersion

– Used on 1550 nm (or 1310 nm)

Simple FP

mirror

gain

cleave

+

- λ

mirror

gain

AR coating

+

- λ

DFB

Passiv

e O

pti

cal N

etw

ork

sPhotodiodes (PD)

• PIN Photodiodes – Good optical sensitivity (∼-22 dBm)– Silicon for shorter λ’s (eg 850nm)– InGaAs for longer λ’s (eg 1310/1550nm)

• Avalanche Photodiodes (APDs)– Higher sensitivity (∼-30 dBm) – Primarily for extended distances in Gb/s rates– Much higher cost than PIN diodes

Passiv

e O

pti

cal N

etw

ork

sTypical PON Configuration

• Wavelengths

• Transceivers

Upstream on 1310nmDownstream on 1490nm

Single Fiber

1310nm.Dual Fiber

PINFP ONU

DFBAPDOLT

DownstreamUpstream

Passiv

e O

pti

cal N

etw

ork

sDownstream Traffic

• Downstream traffic is broadcasted to all ONUs– Weak security

• ONUs filter data (frames) by destintation address

OLTPassiveSplitter

ONU

ONU

ONU

Passiv

e O

pti

cal N

etw

ork

sDownstream Traffic Scheduling

• OLT schedules traffic inside timeslots– Time Division Multiplexing (TDM) scheme

• Time slots can vary from ∼µs to ∼ms

OLTPassiveSplitter

C

A

A B C B

B

AB

CB

A B C B

AB

CB

Passiv

e O

pti

cal N

etw

ork

sDownstream Frame Reception

• Each ONU receives all the frames with the same constant power – Simple receiver (low-cost) @ ONUs

• Frames have preambles/markers

OLT

C

B

A

1 km

3 km

7 km

Passiv

e O

pti

cal N

etw

ork

sUpstream Traffic

• All ONUs share the same upstream channel– ONUs cannot exchange data directly– Collisions may occur at the splitter/combiner

OLTPassiveSplitter

ONU

ONU

ONU

Passiv

e O

pti

cal N

etw

ork

sUpstream Traffic Scheduling 1/4

• Media access mechanisms– Contention-based (similar to CSMA/CD)

• ONUs cannot detect collisions due to directional properties of optical splitter/combiner

– Guaranteed (TDMA, OCDMA, etc.)

OLTPassiveSplitter

C

A

B

A

B B

C

AB

CB

Collision!!

Passiv

e O

pti

cal N

etw

ork


• In general, PON standards propose Time Division Multiplexing Access (TDMA) schemes– Upstream time slicing and assignment

OLTPassiveSplitter

C

A

A B C B

B

A

B B

C

Passiv

e O

pti

cal N

etw

ork


• Typically, downstream traffic carries grants that schedule upstream traffic

• Grant distribution must take into account the different propagation times to reach each ONU

OLTPassiveSplitter

C

A

B

A B C B

2 1 AB

CB

A B C B

AB

CB

2

1

2

1

2 1

10 km

2 km

Passiv

e O

pti

cal N

etw

ork


• PON standards define ranging mechanisms– the method of measuring the logical distance between each

ONU and the OLT and determining the transmission timing such that upstream cells sent from different ONUs do not collide

2

1

OLTPassiveSplitter

C

A

AC

B

A

C

C

10 km

2 km

Passiv

e O

pti

cal N

etw

ork

sUpstream Frame Reception

• The OLT receives frames with different powers– Much difficult to recover synchronism– Burst Mode Receiver (complex) @ OLT

• Sets 0-1 threshold on a burst basis

OLTPassiveSplitter

C

B

A

1 km

3 km

7 km

A

BB A

Passiv

e O

pti

cal N

etw

ork

sPower Budget

• Maximum optical power loss in the ODN– Difference between the TX power and the

sensitivity of the RX

• Considers attenuation of fiber, connectors, splices, splitters, etc.

0.2 dB/km0.3 dB/kmFiber (1490/1550nm)

0.4 dB/km0.5 dB/kmFiber (1310nm)

0.067 dB0.088 dBSplices

0.15 dB0.75 dBConnection

Low-loss Conventional

ODN Loss Model Assumptions

Passiv

e O

pti

cal N

etw

ork

sPassive Splitters

• 1x2 Splitter • 1xN Splitter

• Every time the signal is split two ways, the signal is reduced by 10log(0.5)=3dB

• Loss ∼3dB × log2(#ONUs)

3.4dB3.7dBSplitter 1x2

Low-loss Conventional

Passiv

e O

pti

cal N

etw

ork

sSplitter/Couplers Configurations

4-stage 8x8 3-stage 8x8

Passiv

e O

pti

cal N

etw

ork

s

• Upstream (@1310nm) Power Budget = 30 dB• Downstream (@1490nm) Power Budget = 22 dB

Transceiver Assumptions

-22 dBm0 dBmONU (FP+PIN)

OLT (DFB+APD) -30 dBm1 dBm

RX SensitivityTX Power

Passiv

e O

pti

cal N

etw

ork

sVideo Distribution over PONs

• Video can be distributed in several ways

• RF video signal (overlay video)– Uses the same technology employed in cable TV

networks– Requires a dedicated wavelength and high-power– Supports both analog and digital channels

• IP video signal (integrated video)– Uses IP protocol to delivery video services– Can use the same wavelength as data and voice– Video head end can be shared among many

networks/platforms

Passiv

e O

pti

cal N

etw

ork

s

OLT

RF Video Signal

PassiveSplitter

ONU

ONU

ONU

• A 3rd channel (1550nm) can be used for video• A high-power signal is required for video

– The video signal is amplified by an EDFA at the OLT

EDFA

video

video

video

video

Passiv

e O

pti

cal N

etw

ork

sRF Video Issue: Brillouin Scattering

• All optical fibers have a physical limitation known as stimulated Brillouin scattering (SBS)

• SBS occurs when a high power optical signal over relatively long length (>8km) fiber generates variations in the fiber’s optical properties and scatters optical signals in the reverse direction.

• As power levels increase, so does the effect, resulting in transmitter signal loss and noticeable video signal degradation on a subscriber’s TV

• In general, this results in a power budget of ∼21 dB (@1310nm)

Passiv

e O

pti

cal N

etw

ork

sUpstream Analysis (Conventional ODN)

• Considers only fiber and splitter attenuation

15.67.822.264

60.03001

52.626.33.72

8.24.125.9128

23.011.518.532

30.415.214.816

37.818.911.18

45.222.67.44

Nom. Distance

(km)

Avail. fiber loss

(dB)

Nom. splitting loss (dB)

Split

Each split costs

7.4 km

(12.3%)

Passiv

e O

pti

cal N

etw

ork

sDownstream Analysis (Conv. ODN)


2.70.822.264

76.72301

64.319.33.72

0.0-2.925.9128

15.04.518.532

27.38.214.816

39.711.911.18

52.015.67.44

Nom. Distance

(km)

Avail. fiber loss

(dB)


Split

Each split costs

12.3 km

(14.7%)

Passiv

e O

pti

cal N

etw

ork

sRF Video Analysis (Conventional ODN)


Each split costs

12.3 km

(16.1%)0.0-1.222.264

70.02101

57.717.33.72

0.0-4.925.9128

8.32.518.532

20.76.214.816

33.09.911.18

45.313.67.44

Nom. Distance

(km)

Avail. fiber loss

(dB)


Split

Passiv

e O

pti

cal N

etw

ork

sConventional ODN Analysis

Coonventional ODN

0.0

20.0

40.0

60.0

80.0

100.0

1 2 4 8 16 32 64 128

Number of ONUs (split)

Max

imum

ONU D

ista

nce

[k

m]

Upstream Downstream RF Video

Passiv

e O

pti

cal N

etw

ork

sUpstream Analysis (Low loss ODN)


24.09.620.464

75.03001

66.526.63.42

15.56.223.8128

32.5131732

41.016.413.616

49.519.810.28

58.023.26.84

Nom. Distance

(km)

Avail. fiber loss

(dB)


Split

Each split costs

8.5 km

(11.3%)

Passiv

e O

pti

cal N

etw

ork

sDownstream Analysis (Low loss ODN)


132.620.464

1152301

9819.63.42

0-0.823.8128

306.01732

479.413.616

6412.810.28

8116.26.84

Nom. Distance

(km)

Avail. fiber loss

(dB)


Split

Each split costs 17 km

(14.8%)

Passiv

e O

pti

cal N

etw

ork

sRF Video Analysis (Low loss ODN)


Each split costs 17 km

(16.2%)30.620.464

1052101

8817.63.42

0-2.823.8128

204.01732

377.413.616

5410.810.28

7114.26.84

Nom. Distance

(km)

Avail. fiber loss

(dB)


Split

Passiv

e O

pti

cal N

etw

ork

sLow Loss ODN Analysis

Low loss ODN

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

1 2 4 8 16 32 64 128

Number of ONUs (split)

Max

imum

ON

U D

ista

nce

[k

m]

Upstream Downstream RF Video

Passiv

e O

pti

cal N

etw

ork

sReach/Split Ratio Improvement

• Use of Forward Error Correction (FEC) techniques

• ITU-T G.795– Red Salomon Code– Low frame processing delay (∼12µs)� ∼ 6% overhead– Upto ∼5.5dB gain

• APD ∼ electrical gain (limited by shot noise)• PIN ∼ ½ electrical gain (limited by thermal noise)

• Improvements– Increase 1:32 splits @ 10km– Allow 1:16 km @ 20km

Passiv

e O

pti

cal N

etw

ork

sWhich one is a better design?

10 km

10 km

1 km

1 km

x32

x32

a) b)

Fiber: 0.3dB/kmSplitter: 3dB/split

Passiv

e O

pti

cal N

etw

ork


• a) 0.3 dB + 15 dB + 3 dB = 18.3 dB• b) 3 dB + 15 dB + 0.3 dB = 18.3 dB

10 km

10 km

1 km

1 km

x32

x32

a) b)

No difference at all

Passiv

e O

pti

cal N

etw

ork


10 km

1 km

1 km

x2

x32

a) b)

5 kmx16

5 km1 km

6 km

Fiber: 0.3dB/kmSplitter: 3dB/split

Passiv

e O

pti

cal N

etw

ork


10 km

1 km

1 km

x2

x32

a) b)

5 kmx16

5 km50 km

55 km

• a) = 18.3 dB = 0.3dB+3dB+15dB=18.3dB• b) = 18.3 dB = 3dB+15dB+16.5dB=34.5dB

Passiv

e O

pti

cal N

etw

ork

sOther Design Issues...

• 70 mph• 5.8 in/hr• 30 minPassing: No

evidence of water intrusion

Wind-Driven Rain

Passiv

e O

pti

cal N

etw

ork

sSummary

• PONs are typically made of– cheap components at ONUs– more expensive and performant ones at the OLT

• Upstream traffic scheduling is managed in a centralized fashion by the OLT

• TDM-PONs have limited reach/split performance– 10-20km & 16-32 split ratios

• Standards define– Physical Layer– Downstream and Upstream Frame Formats– Upstream Grant Distribution Mechanism

• Ranging Mechanism

Passiv

e O

pti

cal N

etw

ork

sContents






PON Standardization

Passiv

e O

pti

cal N

etw

ork

sPON Standards

Full Service Access Network (FSAN)

Group

Ethernet in the First Mile (EFM)

Alliance

International Telecommunication

Union (ITU-T)

Institute of Electrical & Electronics Engineers

(IEEE)

APON/BPON (G.983)

EPON (802.3ah)

GPON (G.984)

Propose standards

Ratify standards

Working

Groups

Standards

Bodies

Standards

20042003

1998/2001

Passiv

e O

pti

cal N

etw

ork

sFSAN Members: Service Providers

Passiv

e O

pti

cal N

etw

ork

sEFM Alliance: Equipment Vendors

• Members– AllOptic, Cisco, Elastic Networks, Ericsson, Extreme

Networks, Infineon, Intel, NTT, Passave, Texas Instruments, …

• Position Ethernet in the First Mile as a key networking technology for the access network

• Support the Ethernet in the First Mile standards effort conducted in the IEEE P802.3ah Task Force

Passiv

e O

pti

cal N

etw

ork

sTechnical Standards Comparison

6416 or more32Max PON Splits

20-30 dB21-26 -dB20-30 dBODN Power Budgets

Configurable2.4 Gbps downstream

2.4 Gbps upstream

Symmetric 1.25 Gb/sConfigurable1.2 Gb/s downstream;

622 Mb/s upstream

Maximum Speed

ATM, Ethernet or TDMEthernetATMTraffic Modes

ATM, VoIP or TDMVoIPATMVoice

Either over RF or IP1550 nm overlay (RF) Video

20 km10-20 km10-20 kmReach

53 to 1518 bytes1518 bytes53 bytesData Packet Cell Size

ITU G.984IEEE802ahITU G.983Standard

GPONEPONBPON

Passiv

e O

pti

cal N

etw

ork

sContents






APON

Passiv

e O

pti

cal N

etw

ork

sATM PONs (APONs)

• The first PON standard was based on ATM cells• It consists of:

– Downstream Channel @ 155 Mbps or 622 Mbps– Upstream Channel @ 155 Mbps

• It supported different services:– Digital Broadband Video (No Analog Video)– Multimedia Services– ATM Services

• Those were the ATM days!

Passiv

e O

pti

cal N

etw

ork

sAPON Physical Parameters

Single FiberDual Fiber

Transmission

16 or 32Split Ratio

20 kmMax Reach

Class B: 10-25 dBClass C: 15-30 dB

Power Budget

G.652 (STD SMF)Fiber Type

1310 nm1550 nmDownstream

1310 nm1310 nmUpstream

Dual FiberSingle Fiber

Passiv

e O

pti

cal N

etw

ork

sAPON Architecture (Single Fiber)

Downstream 1550 nm

Upstream 1310 nm

Voice, Video & Data

Optical

Splitter

1x32 Or Cascade

Optical Coupler

Voice, Video and Data Voice, Video and Data

1310 nm 1550 nmDownstreamUpstream

Voice and Data Voice and Data

OLT

Video (l)

Data (AAL5)

POTS (AAL1,2)

ONU

100 nm 100 nm

Passiv

e O

pti

cal N

etw

ork

sDownstream Frame Structure

• Based on STM-1 (155 Mbps) line rate• Each frame (∼150 µs) carries timeslots of 53B

– The frame is long – 56 slots (155 Mbps) → ∼3.6 µs timeslots– 224 slots (622Mbps) → ∼0.9 µs timeslots

• Each timeslot contains – a data cell (ATM)– or a Physical Layer Operation & Management cell

(PLOAM)– Every 28 slots a PLOAM cell is inserted.

Passiv

e O

pti

cal N

etw

ork

sDownstream PLOAM cell

• Downstream PLOAM cells are responsible for– allocating bandwidth (via grant fields), – frame synchronization, – error control,– ranging, – and maintenance.

• Payload of 48 bytes– Carries 27 grants– Each grant, schedules1 upstream ATM cell

Downstream

PLOAM Cell

Passiv

e O

pti

cal N

etw

ork

sDownstream ATM cell

• ONUs filter downstream ATM cells and receive only those that are addressed to them

• Each ATM cell has a 12-bit addressing field associated with a virtual circuit– At most 4096 ATM circuits are allowed per PON

Passiv

e O

pti

cal N

etw

ork

sUpstream Frame Structure

• Each frame (∼150 µs) carries 53 slots of 56 bytes– 53 bytes of ATM or PLOAM cell– 3 overhead bytes per ATM cell

• The 3 overhead bytes contain – at least 4 bits of guard time

• to prevent collisions with cells from other ONUs.

– a preamble field for bit synchronization and amplitude recovery.

– a delimiter field is used to indicate the start of an incoming cell.

Passiv

e O

pti

cal N

etw

ork

sUpstream PLOAM cell

• Upstream PLOAM cells carry– alarms, – alerts – ranging messages– receiver and

transmitter status

• Upstream PLOAM rate– Defined by the OLT for

each ONU– Minimum is 1 PLOAM

every 100 msUpstream PLOAM Cell

Passiv

e O

pti

cal N

etw

ork

sUpstream Traffic Scheduling

• Coupled downstream and upstream timing– Both frames have equal length (∼150 µs) – Synchronization is based on downstream frames

• The OLT, by means of the ranging process, aligns all ONUs upstream frames to an unique downstream frame

• The downstream frame carries grants for ONUs to allow upstream transmission

• One grant = One cell– Data Grant– PLOAM Grant– Divide_Slot Grant– …

Passiv

e O

pti

cal N

etw

ork

sUpstream Minislots

• An upstream slot can contain a divided_slot• The divided_slot fits into one upstream slot and contains a

number of minislots coming from a set of ONUs• The OLT assigns one divided_slot grant to this set of ONUs

for sending their minislots• Minislots are used to report status information of the ONUs

Passiv

e O

pti

cal N

etw

ork

sRanging Process

• The OLT must compute the RTT for each ONU, and sends an equalization delay time to each of them– PLOAM cells are used for this purpose

• ONUs implement the equalization delay to emulate an equidistant network

OLTPassiveSplitter

ONU

ONU

ONU

20 km

20 km

20 km

Passiv

e O

pti

cal N

etw

ork

sAPON Ranging

• OLT sends a Ranging Grant and waits for the ONU response• Once, the OLT has received all responses, it calculates the

equalization delays and communicates this information to the ONUs, who adjust their transmission

Passiv

e O

pti

cal N

etw

ork

sAPON Bandwidth Allocation

• Downstream Bandwidth– bandwidth can be dynamically allocated by the

OLT based on the ONU’s services

• Upstream Bandwidth– bandwidth is allocated statically through grants– minislots mechanism for reporting ONUs’ queues,

but no dynamic bandwidth allocation sheme defined

– No dynamic bandwidth allocation!


BPON

Passiv

e O

pti

cal N

etw

ork

sBroadband PONs (BPONs)

• BPONs are similar to APONs, but add extra functionalities

• Include APONs (G.983.1)• Defined in the ITU-T G.983.3 (2001)• Support higher rates

– Downstream (155, 622 & 1244 Mbps)– Upstream (155 & 622 Mbps)

• Defines– alternative wavelength plan including additional

wavelength band • for downstream video broadcast,

– dynamic upstream bandwidth allocation (G.983.4)– protection mechanisms

Passiv

e O

pti

cal N

etw

ork

sBPON Physical Parameters

Single FiberTransmission

16 or 32Split Ratio

20 kmMax Reach

Class A: 5 - 20 dBClass B: 10-25 dBClass C: 15-30 dB

Power Budget

G.652 (STD SMF)Fiber Type

Passiv

e O

pti

cal N

etw

ork

sBPON Wavelength Allocation

APON

BPON

Water Peak

Passiv

e O

pti

cal N

etw

ork

sBPON Architecture

Downstream 1490 nm

Upstream 1310 nm

Voice & Data

Optical

Splitter

1x32 Or Cascade

Optical Coupler

Video 1550 nm

Voice and Data Voice and Data VideoVideo

1310 nm 1490 nmDownstreamUpstream

1550 nm

Digital TV

Analog TV HD/VOD

550 MHz 860 MHz42 MHz

Voice and Data Voice and Data

EDFA

OLT

Video (l)

Data (AAL5)

POTS (AAL1,2)

ONU

100 nm 20 nm 10 nm

Passiv

e O

pti

cal N

etw

ork

sFrames

Passiv

e O

pti

cal N

etw

ork

sDynamic Bandwidth Allocation (DBA)

• DBA is the process by which ONUs dynamically request upstream bandwidth, and the method the OLT reassign bandwidth accordingly

• BPONs defines two DBA schemes– buffer status reporting (SR)– idle cell monitoring, or no status reporting (NSR)

OLT

ONU-A

ONU-B

ONU-C

ONU-D

Dynamic allocation of bandwidth

Shared bandwidth

Dedicated bandwidth

GRANTS

Passiv

e O

pti

cal N

etw

ork

sTransmission Containers (T-CONTs)

• Entity used for upstream bandwidth allocation– Responsible for requesting and receiving grants– Associated to a buffer and report its status

• A single T-CONT can carry ATM traffic with various service classes and virtual circuits

• A data grant/request is associated with one T-CONT• T-CONTs are essentially “pipes” that carry ATM circuits

Passiv

e O

pti

cal N

etw

ork

sNo Status Reporting (NSR)

• OLT inspects each incoming cell from a specific T-CONT in a predefined time frame– Remembers the ATM connections that are associated with a

specific T-CONT

• For example, the OLT calculates the utilization rate of the currently assigned bandwidth by monitoring the number of effective received cells from specific T-CONTs, and uses this value as the bandwidth request information– The bandwidth allocation reserved for a T-CONT is

INCREASED if the current allocation is largely utilized and DECREASED otherwise

Passiv

e O

pti

cal N

etw

ork

sStatus Reporting (SR) 1/3

• SR-ONUs explicitly report to its OLT PON interface• Since a number of ONUs and their T-CONTs may report

queue lengths of T-CONT buffers, it is imperative to balance the amount of information with the upstream bandwidth consumption of these reports

• Generally the OLT will generate divided_slot grants to request a queue length for the specified ONU according to the service requirements

Passiv

e O

pti

cal N

etw

ork


• When an ONU recognizes a divided_slot grant, the ONU can transfer information in a minislot in the divided_slot

• This minislot contains the queue length for every T-CONT using non-linear coding and CRC-8

Passiv

e O

pti

cal N

etw

ork


• SR-ONUs shall report the queue length of their T-CONTs when requested by their OLT

• The queue length is the sum of the total number of cells in all the class buffers that are connected to a T-CONT

Passiv

e O

pti

cal N

etw

ork

sFault Tolerance

• BPON defines different protection schemes– Based on Automatic Protection Switching (APS)– Duplication of transceivers (TR), splitters and

optical fiber sections

• Similar to metro/core networks

PassiveSplitter

Feeder Section

Drop SectionTR

TR

TR

TR

Passiv

e O

pti

cal N

etw

ork

s

B type1+1 protection of OLT

C type1+1 protection of PON

Protection Mechanisms

• Cost-effective• Redundant feeder• Redundant OLT

transceivers

• Most secure and expensive

• Redundant feeder and drops

• Redundant transceivers

TR

TR

TR

TR

TR

OLTONU-1

ONU-2

ONU-n

TR

TR

TR

TRTR

TR

TR

TR

OLT ONU-1

ONU-2

ONU-n

Passiv

e O

pti

cal N

etw

ork

sContents






EPON

Passiv

e O

pti

cal N

etw

ork

s

Layer 1: physical layer

Layer 2: data link layer

10Mb/s 100Mb/s 1Gb/s 10Gb/s

IEEE802.2 logical link control

IEEE802.1 bridging

IEEE802.3Ethernet

MAC layer

IEEE802.4 Token bus MAC layer

802.3ah EFM

Physical layer

IEEE802.5 Token ring MAC layer

IEEE802.6 MAN MAC layer

IEEE802.11 wireless MAC layer

Physical layer

Physical layer

Physical layer

Physical layer

• EPON started to be standardized by IEEE 802.3ah EFM since 2001, it was ratified in 2004

IEEE 802.3.ah

Passiv

e O

pti

cal N

etw

ork

sEthernet PONs (EPONs)

• All packets carried in EPON are encapsulated in Ethernet frames – Support for variable size packets

• Similar wavelength plan to BPON• Maximum bit rate is 1Gbps (1.25 Gbps 8B/10B)• Minimum number of splits is 16• Maximum reach is

– 10 km (FP-LD @ ONUs, limited by dispersion)– 20 km (DFB-LD @ ONUs)

• Different configurations are allowed

Passiv

e O

pti

cal N

etw

ork

sEPON Configurations

(1) Tree Topology (2) Ring Topology

(3) Tree with Redundant Trunk (4) Bus Topology

OLT

ONU

ONU

ONU

ONU

OLT

ONU

ONUONU

ONU

OLT

ONU ONU

ONU ONU

OLT

ONU

ONU

ONU

ONU

Passiv

e O

pti

cal N

etw

ork

sDownstream Traffic

• Similar to a shared medium network • Packets are broadcasted by the OLT and selected

by their destination ONU

Passiv

e O

pti

cal N

etw

ork

sUpstream Traffic

• ONUs synchronized to a common time reference • Centralized arbitration scheme• OLT grants access to ONU for a timeslot

– Several Ethernet packets

Passiv

e O

pti

cal N

etw

ork

sIEEE 802 Compliance

• IEEE 802 assumes all stations to be connected to a shared-medium (single access domain)

• Single-station domains connected by point-to-point links form a switched LAN

• Problem: IEEE 802 compliance – ONUs cannot communicate with one another due to

directivity of passive devices

• 1st Solution: Emulate a point-to-point topology– Loss of useful downstream broadcast nature

• 2nd Solution: Emulate a point-to-point topology but with a special broadcast feature

Passiv

e O

pti

cal N

etw

ork

sLogical Topology Emulation (LTE)

• PON devices implement a logical topology emulation (LTE) function– To preserve the existing Ethernet MAC operation,

LTE must reside below the MAC sublayer

• Emulation relies on tagging Ethernet frames– Logical Link Identification (LLID) – Replaces 2 bytes of 8 of the Ethernet preamble

Passiv

e O

pti

cal N

etw

ork

sEPON Ethernet Tagging

• Unicast LLID– Established between the OLT and each ONU– Point-to-point links– ONUs filter frames by their assigned LLID

• Universal LLID– Used to define a broadcast service– Received by all ONUs– Exploits downstream broadcast nature of PONs!

Passiv

e O

pti

cal N

etw

ork

sThe Muti-Point Control Protocol (MPCP)

• Original Ethernet MAC protocol cannot operate properly in the upstream channel (no collision detection)

• MPCP (Multi-Point Control Protocol) – In-band signalling– Messages (64 bytes)

• GATE • REGISTER• REGISTER_REQUEST• REGISTER_ACK• REPORT

Passiv

e O

pti

cal N

etw

ork

sMPCP Modes of Operation

• Auto Discovery Mode– Detects newly connected ONUs and learns the

round-trip delay and MAC address of that ONU– Messages: GATE, REGISTER, REGISTER_REQUEST,

REGISTER_ACK

• Bandwidth Assignment Mode – Assigns transmission opportunities to registered

ONUs– Messages: GATE, REPORT

Passiv

e O

pti

cal N

etw

ork

sAuto Discovery Mode (1/6)

• OLT allocates an initialization slot, an interval of time when no previously initialized ONUs are allowed to transmit

• OLT sends an initialization “discovery” GATE message advertising the start time of the initialization slot and its length

Passiv

e O

pti

cal N

etw

ork


• Only un-initialized ONUs will respond to the message• When the local clock located in the ONU reaches the start

time of the initialization slot, the ONU will transmit REGISTER_REQ message

• When the OLT receives the REGISTER_REQ from an un-initialized ONU, it learns its MAC address and round-trip time

Passiv

e O

pti

cal N

etw

ork


Passiv

e O

pti

cal N

etw

ork


• The OLT sends a REGISTER message containing the unicast Logical Link ID (LLID)

Passiv

e O

pti

cal N

etw

ork


• The OLT sends a GATE message containing a grant for the the unicast LLID

Passiv

e O

pti

cal N

etw

ork


• The ONU acknowledges the registration by sending a REGISTER_ACK message

Passiv

e O

pti

cal N

etw

ork

sAuto Discovery Summary

Passiv

e O

pti

cal N

etw

ork

sBandwidth Assignment Mode

• The OLT sends a GATE message (grant) and schedules upstream transmission for a specific time interval

• ONUs send REPORT messages with their queue status claiming grants

Passiv

e O

pti

cal N

etw

ork

s“Just-in-Time” Scheduling

• The GATE message is sent so that when the ONU receives the message it starts transmitting– Only time length of access interval is needed

• However, Ethernet frames cannot be preempted so collision may occur

Passiv

e O

pti

cal N

etw

ork

s“Start Time” Scheduling

• The GATE message carries– a Start Time,– and its length

• Requires a common time reference (16ns granularity)

Passiv

e O

pti

cal N

etw

ork

sMPCP Clock Synchronization

• Both the OLT and the ONU have 32-bit counters that increment every 16 ns– These counters provide a local timestamp

• MPCP messages contain a timestamp field

• When the ONU receives a MPCP message, it sets its counter according to the value in the timestamp of the received message– Local clock is then “synchronized” with the OLT

one

Passiv

e O

pti

cal N

etw

ork

sRanging

• When either device transmits a MPCP message, it maps its counter to the timestamp field– Useful for the ranging process

RTT = T2 - T1

Passiv

e O

pti

cal N

etw

ork

sREPORT Message

• REPORTs are generated at the ONU

• A REPORT message may contain queue reports (DBA)• REPORT messages can be used with timestamps only (Ranging)

• The OLT must – process REPORT messages– consider the REPORT when allocating bandwidth

• REPORTs must be issued periodically

Passiv

e O

pti

cal N

etw

ork

sContents






GPON

Passiv

e O

pti

cal N

etw

ork

sFrom BPON to Gigabit PON (GPON)

• BPON Issues– Shortage of bandwidth in connecting Gigabit

Ethernet – Inefficient allocation of packets due to AAL5– High cost of interface cards due to low penetration

of ATM– Relatively insignificant role played by ATM in the

core network

Passiv

e O

pti

cal N

etw

ork

sGPON Standardization

Feb. 2004

G-PON TC layer spec.(Transmission convergence layer specification)

G.984.3

Mar. 2003

G-PON Physical Layer spec.(Physical Media Dependent (PMD) layer specification)

G.984.2

Mar. 2003

G-PON service requirements(General characteristics)

G.984.1

AdoptionOutlineITU-T

Passiv

e O

pti

cal N

etw

ork

sG.984.1 Service Requirements

Downstream video wavelength (1550 – 1560nm) may be overlaid

Class A, B and C (As B-PON, G.982 is applied)ODN classes

Downstream: 1480 – 1500nmUpstream: 1260 – 1360nm

Wavelength allocation

Max. 64 in physical layerBranches

Max. 60 kmLogical reach

Max. 20 km or max. 10 kmPhysical reach

1.25Gbit/s symmetric or higher (2.4 Gbit/s). Asymmetric with 155/622Mb/s upstream

Bit rates

TargetItem

Passiv

e O

pti

cal N

etw

ork

sG.984.2 Physical Requierements

LD + PIN (APD may also be used)

Up to 20km: use of FP with FEC (FEC is not needed when using DFB)

4Bytes (155.52Mbit/s), 8Bytes (622.08Mbit/s)12Bytes (1.244Gbit/s), 24Bytes (2.488Gbit/s)

Overhead in upstream signal

Optical devices

Up to 10km: use of FP without FECCorrection of errors due to dispersion

1.244Gbit/s and 2.488Gbit/s symmetricalAsymmetrical with 155.52/622.04 Mbit/s upstream

Bit rates

Spec.Item

Passiv

e O

pti

cal N

etw

ork

sG.984.3 Transmission Convergene (TC)

• ATM ATM services are carried by ATM frames• Other services are in principle carried by Generic frames• A mix of the two types of frame can be configured

ATM service Other services

Layer 2

Layer 3

Layer 4

Layer 5or higher

Layer 1

ATM frame

PON-PHY

TCP+UDP etc.

IP

Ethernet

Generic frame

T1/E1TDM

POTS VideoData

VoIP

G.983 base G.707 base

ATM

GPON TC (GTC) frame

AAL

Passiv

e O

pti

cal N

etw

ork

sMultiplexing Mechanisms

• T-CONT entity (as BPON): associated to ports and/or VP/VC

Passiv

e O

pti

cal N

etw

ork

sGPON Encapsulation Mode (GEM)

• GEM provides a Generic Frame where to carry both TDM and packet traffic over fixed data-rate channels– Similar Generic Framing Procedure (GFP) used in

SDH/SONET

• A Generic Frame consists of:– a core header– a payload header– an optional extension header– a payload– an optional frame check sequence (FCS).

Passiv

e O

pti

cal N

etw

ork

sMapping Modes

• Framed– Optimized for bandwidth efficiency at the expense

of latency– It encapsulates complete Ethernet (or other types

of) frames with a GEM header

• Transparent– Used for low latency transport of block-coded client

signals such as GbE, Fibre Channel, ESCON, FiCON, and Digital Video Broadcast (DVB)

– Small groups of 8B/10B symbols are transmitted rather than waiting for a complete frame of data

Passiv

e O

pti

cal N

etw

ork

sGPON-TC (GTC) Frames

• Fixed frame duration (125us)• Transports both ATM cells and GEM Frames• Used in both downstream (DS) & upstream (US)

– Use of Pointers to allocate upstream bandwidth

Passiv

e O

pti

cal N

etw

ork

sUpstream Scheduling

• Downstream frames indicate permitted locations for upstream traffic– Use of pointers (byte units)

• Minimum bandiwdth allocation 64Kbps (1 byte @ 125us)

– Upstream frames synchronized with downstream ones

Passiv

e O

pti

cal N

etw

ork

sDownstream Frame Structure 1/3

• It consists of– a Physical Control Block Downstream (PCBD)– the ATM partition (N×53 bytes)– the GEM partition

Passiv

e O

pti

cal N

etw

ork


• The PBCD carries basically– Synchronization fields (used by ONUs)– Upstream Bandwidth grants (upstream access)

Passiv

e O

pti

cal N

etw

ork


• Each Access grants is composed of– an AllocId associated with the T-CONT– a Start Time and Stop Time expressed in bytes that indicate

when to access the usptream channel and when to release it

• As in BPONs, upstream access is effectively done delaying access for a specific equalization delay

Passiv

e O

pti

cal N

etw

ork

sDownstream Frame Structure

Passiv

e O

pti

cal N

etw

ork

sUpstream Frame Structure 1/3

• Each frame contains transmissions from one or more ONUs

• Four types of overheaders are present

– Physical Layer

– PLOAM

– Power Leveling

– Dynamic Bandwidth Report

Passiv

e O

pti

cal N

etw

ork


• A preamble and a delimiter are attached to each burst in order to recover the frame at the OLT

• Their values are absolute in time and variables in bits

Passiv

e O

pti

cal N

etw

ork

sUpstream Burst Lock-In Time

• BPON: stringent lock-in 3 bytes per cell timing

• GPON: more relaxed timing– 622 Mbps upstream: 8 bytes– 1.2 Gbps upstream: 12 bytes– 2.4 Gbps upstream: 24 bytes

• Results:– BPON = stringent timing = more expensive

components– GPON = more relaxed timing = cheaper

components– GPON = lowest cost path for higher bandwidth

Passiv

e O

pti

cal N

etw

ork


• The usptream frame payload can be used to carry– ATM cells,– GEM frames– or DBA reports

Passiv

e O

pti

cal N

etw

ork

sDBA Reports


TDM-PON Summary

Passiv

e O

pti

cal N

etw

ork

sTechnical Summary

Decoupled TDMA

200420032001Year of

introduction

IP-based servicesFull services

(phone, IP, TDM)ATMServices provided

TDMA coupled to DownstreamUpstream

bandwidth control

PossibleWavelength

multiplexing of video

1.3/1.5Wavelength (µ m)

1.25G(1G after decoding)

1.2G, 2.4G, 156M (upstream), 622M (upstream)

156M, 622M, 1.2G (downstream)

Transmission speed(bit/s)

EthernetGEM(partly ATM)

ATMTransmission

frame

EFM/IEEEFSAN/ITU-TG.984 series

FSAN / ITU-TG.983 series

Standardization

EPONGigabit Ether-PON

GPONGigabit-PON

BPONBroadband-PON

Type of PON

Passiv

e O

pti

cal N

etw

ork

sReach/Split

10 20Applicable distance (km)

0

10

20

30

Nu

mb

er

of

sp

lits

EPONClass PX20

G(B)PONClass B

G(B)PON Class C

Assumptions for calculationOptical splitter insertion loss

32-way split: 17dB 16-way split: 14dB 8-way split: 11dB 4-way split: 8dB

Fixed loss (conn., etc.): 4dBLine loss:0.5dB/km

G(B)PON Class AEPON Class PX10 (note)

Difference between sending and receiving levels

G(B)PONClass A: 5-20dBClass B: 10-25dBClass C: 15-30dBEPONClass PX10: 5-20dBClass PX20: 10-24dB

Passiv

e O

pti

cal N

etw

ork

sTransmission Efficiency

0

200

400

600

800

1000

1200

1400

EPON GPON BPON

Mb/

s

scheduling OH : framedelineation

scheduling OH : PHY burst OH

scheduling OH : controlmessages

payload encapulation OH

line coding

payload

Passiv

e O

pti

cal N

etw

ork

sHeader’s Comparison

Guard PreambleDelimiterGPON

EPON

min. 25.6 ns

typ. 35.2 ns

typ. 16.0ns

min. 76.8 ns

Data

Laser turn on time

AGC, CDRsetting time

Data

max. 400 ns max. 400 ns

Guard PreambleDelimiterBPON

min. 4 bits

typ. 12 bits

typ. 8 bits

24 bits

Data

AGC: Automatic Gain Control; CDR: Clock and Data RecoveryLaser turn on time overlaps the laser turn off time of the previous burst

Laserturn off time

max. 400ns

Data

EPON costs about ~10% the cost of

BPON/GPON

Passiv

e O

pti

cal N

etw

ork

sContents






WDM-PONs

Passiv

e O

pti

cal N

etw

ork

sFiber

• Single Mode Fiber (SMF) to achieve large distances– ITU G.652 SMF (STD)

• “water peak” attenuation renders the 1360nm–1480nm spectrum unusable for data transmission.

– ITU G652c/d SMF (ZWP)• “zero-water peak”

800 900 1000 1100 1200 1300 1400 1500 1600 1700

0.5

1.0

1.5

2.0

2.5

3.0

FirstWindow Second

Window

ThirdWindow

ATTEN

UA

TIO

N (

dB

/km

)

WAVELENGTH (nm)

1310nm

1550nm

850nm

STD SMF

ZWP SMF

Passiv

e O

pti

cal N

etw

ork

sCoarse WDM (CWDM)

• Upto 18 channels (1271-1611nm, 20 nm spacing)• Cheap transmitters (no strict tuning, thus, no thermal

control needed)• Reach limited by the lowest wavelength

Passiv

e O

pti

cal N

etw

ork

sArrayed Waveguide Gratings (AWG)

• AWG has already been used in many long-haul WDM systems – mulitplexer/demultiplexers– add/drop multiplexer

• AWGs route each specific ingress wavelength to a unique output port

• AWG insertion loss is 4-5dB regardless of the number of channels– Thus, larger distances can be reached

Passiv

e O

pti

cal N

etw

ork

sWDM Techniques in PONs

• WPON: Broadcast and select PONs• WRPON: wavelength routed PONs

– Include AWGs

Passiv

e O

pti

cal N

etw

ork

sSuper-PON

• Extends reach (∼100km) and split ratio (∼2000)– Uses repeaters with optical amplifiers – Uses several wavelengths (DWDM)

Passiv

e O

pti

cal N

etw

ork

sSimple WDM-PON

• Number of ONUs limited by wavelengths• Point-to-point topology• Long-reach (almost point-to-point reach)

Passiv

e O

pti

cal N

etw

ork

sComposite-PON (CPON)

• Downstream uses AWG (improves reach)• Upstream uses combiner

Passiv

e O

pti

cal N

etw

ork

sLARNET

• Downstream AWG routes wavelengths (reach)• Upstream AWG separates wavelengths (low cost

1310nm LD) and improves bandwidth

Wideband upstream signals are “sliced” by the AWG

Passiv

e O

pti

cal N

etw

ork

sRITENET

• Upstream transmitters in ONUs modulate a downstream-broadcatsed unmodulated carrier (no need of light sources at ONUs)

Passiv

e O

pti

cal N

etw

ork

sMultistage-PON

• AWG size is limited by fabrication technology limits → multiple stages of AWGs

• Wavelengths are routedin groups at the 1st stage and individually at the 2nd

Passiv

e O

pti

cal N

etw

ork

sSUCCESS-DWA PON

• Offers dynamic wavelength allocation (DWA) by adding tunable lasers at the OLT

OLT

ONUs

Filter

Passiv

e O

pti

cal N

etw

ork

sContents





Passiv

e O

pti

cal N

etw

ork

sReferences 1/2

• ITU-T Recommendation G.983.1, .Broadband optical access systems based on Passive Optical Networks (PON)., Oct 1998.

• ITU-T Recommendation G.983.3, .A broadband optical access system with increased service capability by wavelength allocation., March 2001.

• ITU-T Recommendation G.983.4, .A broadband optical access system with increased service capability using dynamic bandwidth assignment., Nov. 2001.

• ITU-T Recommendation G.983.5, .A broadband optical access systemwith enhanced survivability., Jan 2002.

• IEEE Standard 802.3AH, .CSMA/CD access method and physical layer specifications Amendment: Media Access Control Parameters, Physical Layers and Management Parameters for Subscriber Access Networks., June 2004.

• ITU-T Recommendation G.975, .Forward error correction for submarine systems., Oct. 2000.

• ITU-T Recommendation G.984.1, .Gigabit-capable Passive Optical Networks (G-PON): General characteristics., March 2003.

• ITU-T Recommendation G.984.2, .Gigabit-capable Passive Optical Networks (G-PON): Physical Media Dependent (PMD) layer specification., March 2003.

• ITU-T Recommendation G.984.3, .Gigabit-capable Passive Optical Networks (G-PON): Transmission convergence layer specification,. Feb. 2004.

• ITU-T Recommendation G.984.4, .Gigabit-capable Passive Optical Networks (G-PON): ONT management and control interface specification., June 2004.

• ITU-T Recommendation G.7041/Y.1303, .Generic Framing Procedure (GFP)., Dec. 2001.

Passiv

e O

pti

cal N

etw

ork

sReferences 2/2• Kramer, Glen. Ethernet Passive Optical Networks, McGraw-Hill, March, 2005 • Lallukka, Sami & Raatikainen, Pertti. Passive Optical Networks. Espoo 2006. VTT

Publications 597. • Effenberger F. J., Ichibangase H. & Yamashita H. Advances in Broadband Passive

Optical Networking Technologies.. IEEE Communications Magazine, Dec. 2001, pp. 118.124.

• Bonenfant, P. & Rodriquez-Moral, A. .Generic Framing Procedure (GFP): The Catalyst for Efficient Data over Transport,. IEEE Communications Magazine, May 2002, pp. 72.79.

• A. Banerjee, Y. Park, F. Clarke, H. Song, S. Yang, G. Kramer, K. Kim, and B. Mukherjee, "Wavelength-division-multiplexed passive optical network (WDM-PON) technologies for broadband access: a review [Invited]," J. Opt. Netw. 4, 737-758 (2005)

• R. D. Feldman, E. E. Harstead, S. Jiang, T. H. Wood, and M. Zirngibl, “An evaluation of architectures incorporating wavelength division multiplexing broad-band fiber access,” J. Lightwave Technol. 16, 1546–1558 (1998).

• M. Zirngibl, C. H. Joyner, L.W. Stulz, C. Dragone, H. M. Presby, and I. P. Kaminow, “LARNET, a local access router network,” IEEE Photon. Technol. Lett. 7, 215–217 (1995).

• N. J. Frigo, P. D. Magill, T. E. Darcie, P. P. Iannone, M. M. Downs, B. N. Desai, U. Koren, T. L. Koch, C. Dragone, and H. M. Presby, “RITENet: a passive optical network architecture based on the remote interrogation of terminal equipment,”

• G. Mayer, M. Martinelli, A. Pattavina, and E. Salvadori, “Design and cost performance of the multistage WDM PON access networks,” J. Lightwave Technol. 18, 121–142 (2000).

• Van de Voorde, I., Martin, C., Vandevege, J. & Qiu, X. .The SuperPON Demonstrator: An Exploration of Possible Evolution Paths for Optical Access Networks., IEEE Comm. Magazine, Feb. 2000, pp. 74.82.

• Y. Hsueh, M. Rogge,W. Shaw, S. Yamamoto, and L. Kazovsky, “Quality of service support over SUCCESS-DWA: a highly evolutional and cost-effective optical access network,” presented at the Optical Fiber Communication Conference, Anaheim, California, 6–11 March 2005.

passive optical networks - materias.fi.uba.armaterias.fi.uba.ar/7543/2011-01/download/pon_e1... ·...

Documents