passive optical network introduction

http://fttwho.blog.sohu.com 8/20/2009宽带通信 * 点滴生活 [email protected]

Passive Optical NetworksIntroduction

Aug, 2009

http://fttwho.blog.sohu.com 宽带通信 * 点滴生活 [email protected] 2009.8 P2

Overview

• Why PON (Passive Optical Network)

• PON Architecture & Applications

• PON Technology

• Next Generation


More and More bandwidth for more and more services

HDTV

VOD movies and programs

with interactive programs, on multipleTV sets or PCs

video gameson-line or download

video blogs / online photosfor digital cameras and camcorders

simultaneous and symmetrical usagemultiple equipments

streaming or download

online storage and back-up

data security for consumers and SoHo's

New needs emerging beyond what adsl and cable provide


Bandwidth in Access Network


FTTH is enabling new usage patterns right now

fiber access

download and upload at 100mbps

ADSL access

download at 8mbps

upload at 1mbps

full HD quality movie 30 Gb 40min >8h >66h

DVD quality movie 4.8 Gb

6min 30s 1h 20min >10h

amateur quality video800 Mb

1min 13 min 1h 40min

20 photos with uncompressed 8M pixels

480 Mb

40s 8 min > 1h

10 MP3 music tracks 40Mb 3s 40 sec 5 min


FTTH modes

• Point-to-Piont (Star) • N/2N fibers• 2N transceivers

• Active Optical Network (AON) • Minimum fiber• 2N ＋ 2 transceivers• Electrical Power in the field

• PON-P2MP • Minimum fiber• N ＋ 1 transceivers• Minimum fibers / space in CO• No electrical power in field• Uniform management• Downstream broadcast (Video)

PTP

PTP Curb

PTMP

N/2N fiber2N transceivers

Minimum fiber2N+2 transceivers

Minimum fiberN+1 transceivers

N subscribers

N subscribers

N subscribers


Overview

• Why PON


• PON Technology

• Next Generation


PON Architecture

OLT: Optical Line Terminal ODN: Optical Distribution Network ONU: Optical Network Unit


PON Architecture (cont.)

PON system: OLT + ODN + ONU + EMS/NMS


Basic Architecture of PON


PON Application - FTTx


PON Services: Data + Voice + Video


Overview

• Why PON


• PON Technologies

• Next Generation


PON Alphabet

APON

BPON

GPON

EPON

GEPON

WDMPON10GEPON

TDM-PON

NGPON DPONRFPON


Passive Optical Network (PON) System Characteristics

• Fiber Optic Media – All PON systems are based a point-to-multipoint physical topology where a single

feeder fiber from the local exchange office is shared by a group of subscriber optical terminals (typically 32 or more)

– A passive optical splitting device (i.e., power splitter or WDM splitter) is used to couple the optical signals from the shared feeder fiber to the individual subscriber (distribution) fibers, and vice-a-versa.

• Active Electronics – A single optical transceiver in the exchange is shared by a group of subscriber optical

terminals (typically 32 or more) – For a fiber-to-the-premises (FTTP) systems, there is generally no active electronics in

the outside plant. – The various PON technologies make use of different multiplexing techniques to allow

shared access to the fiber media• TDM-based PONs and WDM-based PONs are two broad categories• TDM-based PONs are by far the most commonly deployed

– The various PON technologies also differ in available digital capacity, how they dynamically allocate upstream bandwidth to subscribers (for efficient PON bandwidth utilization), and embedded operations capabilities (just to mention a few examples)


TDM PON Example• Downstream – TDM transmission with multiple “listeners” (encryption to insure

privacy)• Upstream – TDMA transmission with upstream transmissions (bursts) scheduled

to prevent overlap

PONs are (in some sense) like HFC systems – shared medium

Downstream (single -fiber systems): 1490 nm Upstream: 1310 nm RF video (if present) 1555 nm

TDM Time Division Multiplex TDMA Time Division Multiple Access CC Cross Connect NB Narrow Band BB Broadband OLT Optical Line Termination ONT Optical Network Termination

TDM ONT2

ONT32

1:32 Optical splitter (or 1:64 for shorter reaches or

with Reach Extender)

OLT

Access Node

NB

BB CC Video

Data

E1/T1/ Telephony

Data

E1/DS1

GbE STMn/OCn

ONT1

E1/DS1/ Telephony

POTS

VOIP

(and/or)

TDMA

Up to 60 km* physical reach

(* with G.984.6 Reach Extender)


WDM-PON Example


Hybrid WDM-PON Example

Access node

OLT

SNI

wavelength splitter

1 to N s on single fiber

Wavelength selection here

dedicated pair

dedicated pair

ONTBitrate 1

ONTBitrate 2

Feeder Fiber

Colorless ONTs: Transmitter and Receiver front-end filter characteristics are wavelength adaptable

power splitter

TDMAONT

(Fixed Optics)

TDMAONT

(Fixed Optics)power

splitter

Hybrid WDM-PON example

* “Fixed” optics might be a cost reduced version of convention DWDM long-haul optics NOTE: Most believe adaptable optics will be required for a practical WDM-PON system


Today’s PON Systems

• TDM-PONs Rule: The vast majority of PON systems deployed today are TDM-based PON systems (i.e., B-PON, E-PON, and G-PON)– They almost exclusively operate on a single fiber, with WDM used to

provide bi-directional transmission – A third wavelength in the downstream is sometimes used for

broadcast video services (e.g., Verizon FiOS)

• WDM-PON: Very limited deploys, mainly in Korea – Costs of WDM-PON in delivering mass market dedicated

wavelength services are still higher high relative to TDM-PON– WDM and hybrid WDM-PONs are expected to play a greater role in

Next Generation (NG) PON systems (e.g., 5+ years) than today


TDM PON Architecture and Technologies

OLT

FiberBP

ON

GP

ON

Max 32 way split (may be cascaded)

OLT implementations may not necessarily support all PON technologies indicated

•Typically: 622 Mbps/155 Mbps (down/up)

•ATM-based transport

LU #1

LU #N, N ≤32

Fiber

Max 64 way split [constrained by PMD attenuation limits]

• Typically: 2488/1244 Mbps

• GFP-like transports (Ethernet, and/or TDM)LU #1

LU #N, N ≤64

EP

ON

Fiber

• 1250 Mbps/1250 Mbps [~850 Mbps effective payload rate])

• Ethernet-based transport

LU #1

LU #N, N ≤32

20 km Maximum Reach

20 km ONU differential range

B-PON

G-PON

E-PON

Max 32 way split (16-way specified in standard)

splitter

splitter

splitter

ITU-T G.983.x

ITU-T G.984.x

1000BASE-PX20 per IEEE 802.3ah

Network optical transceiver (TXR) shared by “N” subscribers

TXR

TXR

TXRLU #N, N ≤32

ONT

ONT

ONT


G.984.5 published

G.984.1, G.984.3G.984.4 Rev2 published

G.984.2 amd2, G.984.6 published

10G-EPON Study started: 2007

NG-PON Study started: 2008

IEEE begins 10GEPON

x-PON Technology Time Line

1995 2000

FSANfounded

‘98 ‘99 ‘02 ‘04 ‘05 ‘06‘01

BPON (ITU G.983.1)

published BPON OMCI

(G.983.2) published

IEEEEPONbegins

FSAN begins GPON

‘03

BPON OMCI

(G.983.2) Revised

GPON OMCI (G.984.4) published

GPON TC (G.984.3) published

IEEE 802.3ah (EPON) published

1st GPON Interop Event

FSAN begins NG-PON

FSAN GPON CTS

BPON Completed: April 2000

BPON 1st Interop Event: March 2004

BPON 1st wide-scale deployment: May 2004

GPON Completed: June 2004

GPON 1st Interop Event: Jan 2006

GPON 1st wide-scale deployment: 4Q 2007

‘07 ‘08

7th GPON Interop Event

‘09

EPON Completed: June 2004

EPON 1st Interop Event: Jan 2006

EPON 1st wide-scale deployment: 2005


EPON - Downsteam


EPON - Upstream


EPON: Ethernet Simple, Fiber Fast

• Standard: IEEE802.3

• Simple as traditional Ethernet: – EPON Media Access Control (MAC) uses Ethernet framing and line coding.

– Downstream channel uses true broadcast.

– Packets extracted by the MAC addresses.

– Not different from any shared-medium Ethernet LAN.

• More concerns– Multiple access for Upstream transmission & Timing sychnization

• MPCP (MultiPoint Control Protocol is introduced)

– QoS on PON• Dynamical Bandwidth Allocation Algorithm & 802.1d

– Optical power planning

– ONU discovery & activiation

– Security


BPON Standards

• Produced in the Full Services Access Network (FSAN) forum– Established by the World’s Telecom operators– Requirements driven approach

• Standardized in the ITU-T– G.983.1 R– Basic architecture, PMD and TC for ATM-based B-PON– G.983.2 R2 – Operations Management Communications Interface – G.983.3 – WDM enhancement, for video overlays on B-PON

• G.983.3 A1 – Support for higher bit rates• G.983.3 A2 – Optical best practices for B-PON

– G.983.4 – DBA enhancement, for efficient bandwidth distribution – G.983.5 – Survivability enhancement, for protection switching


GPON Standards

• GPON is chartered as the ‘next step’ of PON evolution– Address rates greater than 1 Gb/s– To optimize the physical layer for these speeds– More packet-oriented, but still full service

• GPON draws on the B-PON series, but is distinct from it

• GPON standards split into four layers– G.984.1: Requirements – G.984.2: Physical layer – G.984.3: Transmission Convergence layer– G.984.3 A1: Refinements to TC layer

– G.984.4: Management layer– G.984.4 A1: Refinements to Management layer


622/155 BPON Frame Structure

• Frames aligned at ATM cell boundaries

• DS PLOAM cells:– Synchronization

– OAM channel

– Upstream bandwidth assignment (53 grants)

• US PLOAM as needed (VPI=VCI=0)

• US byte overhead:– Cell synchronization and

delineation


GPON Frame Structure

• Frame size fixed at 125 s

• Supports ATM and GEM payload within the same frame

• PCBd:– Synchronization

– DS OAM channel

– Upstream bandwidth map (one byte granularity)

– Downstream structure

• PLOu:– Synchronization for the new

transmitter

• PLOAMu: – US OAM channel

DOWNSTREAM FRAME

UPSTREAM FRAME


Overview

• Why PON


• PON Technologies

• Next Generation


Next Generation of PON

• EPON => 10G-EPON– IEEE802.3av– To be finalized in 2009

• GPON => NG-PON– ITU-T G.984.5: Enhancement Bandwidth– ITU-T G.984.6: Optical Reach Extension

• WDM-PON– No standard activities

• RFOG ( RF-PON)– SCTE-IPS910 – Expected to be published in 2009


10G-EPON

• Two modes:– 10G downstream, 1G upstream– 10G downstream, 10G upstream

• Back compliant with current EPON standard


NG-PON

• Still in researching phase

• Two proposals:– NG-PON1 (2009 – 2012) : ITU G.987– NG-PON2(2012-2015)

• Wavelength


WDM-PON• Advantages:

– High bandwidth

– Protocol/data rate transparency

– High Scurity

• Disadvantages:– Inefficiency in the bandwidth utilization

– Difficult in the wavelength tuning => colorless ONU

– Difficult in the cascaded topology

• In researching phase


RFoG (RFPON)

passive optical network introduction

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