Passive Optical Networks Introduction
Aug, 2009
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Overview • Why PON (Passive Optical Network) • PON Architecture & Applications • PON Technology • Next Generation
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2009.8
P2
More and More bandwidth for more and more services HDTV with interactive programs, on multiple TV sets or PCs VOD movies and programs streaming or download video games on-line or download video blogs / online photos for digital cameras and camcorders online storage and back-up data security for consumers and SoHo's simultaneous and symmetrical usage multiple equipments
New needs emerging beyond what adsl and cable provide http://fttwho.blog.sohu.com
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2009.8
P3
Bandwidth in Access Network
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2009.8
P4
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2009.8
P5
FTTH is enabling new usage patterns right now fiber access
ADSL access
download and upload at 100mbps
download at 8mbps
upload at 1mbps
30 Gb
40min
>8h
>66h
DVD quality movie
4.8 Gb
6min 30s
1h 20min
>10h
amateur quality video
800 Mb
1min
13 min
1h 40min
20 photos with uncompressed 8M pixels
480 Mb
40s
8 min
> 1h
40Mb
3s
40 sec
5 min
full HD quality movie
10 MP3 music tracks
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2009.8
P6
FTTH modes •
Point-to-Piont (Star) • •
N/2N fibers 2N transceivers
N/2N fiber 2N transceivers
PTP •
Active Optical Network (AON) • • •
•
N subscribers
Minimum fiber 2N + 2 transceivers Electrical Power in the field
Minimum fiber 2N+2 transceivers
PTP Curb
N subscribers
PON-P2MP • • • • • •
Minimum fiber N + 1 transceivers Minimum fibers / space in CO No electrical power in field Uniform management Downstream broadcast (Video)
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Minimum fiber N+1 transceivers
PTMP
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N subscribers
2009.8
P7
Overview • Why PON • PON Architecture & Applications • PON Technology
• Next Generation
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2009.8
P8
PON Architecture
OLT: Optical Line Terminal
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ODN: Optical Distribution Network
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ONU: Optical Network Unit
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2009.8
P9
PON Architecture (cont.)
PON system: OLT + ODN + ONU + EMS/NMS http://fttwho.blog.sohu.com
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2009.8
P10
Basic Architecture of PON
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2009.8
P11
PON Application - FTTx
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2009.8
P12
PON Services: Data + Voice + Video
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2009.8
P13
Overview • Why PON • PON Architecture & Applications • PON Technologies • Next Generation
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2009.8
P14
PON Alphabet
TDM-PON
GEPON
APON
BPON
EPON
WDMPON
10GEPON
GPON
DPON
NGPON
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RFPON 2009.8
P15
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) http://fttwho.blog.sohu.com
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2009.8
P16
TDM PON Example • Downstream – TDM transmission with multiple “listeners” (encryption to insure privacy) • Upstream – TDMA transmission with upstream transmissions (bursts) scheduled to prevent overlap Downstream (single -fiber systems): Upstream: RF video (if present)
E1/DS1/ Telephony
1490 nm 1310 nm 1555 nm
ONT1 Access Node E1/DS1
NB
(and/or) GbE STMn/OCn
TDM TDMA CC NB BB OLT ONT
CC
Data
TDM
VOIP
ONT2 OLT
BB
Time Division Multiplex Time Division Multiple Access Cross Connect Narrow Band Broadband Optical Line Termination Optical Network Termination
E1/T1/ Telephony
1:32 Optical splitter
Video
(or 1:64 for shorter reaches or with Reach Extender)
TDMA
POTS
ONT32
Data
Up to 60 km* physical reach (* with G.984.6 Reach Extender)
PONs are (in some sense) like HFC systems – shared medium http://fttwho.blog.sohu.com
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2009.8
P17
WDM-PON Example
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2009.8
P18
Hybrid WDM-PON Example Hybrid WDM-PON example wavelength splitter TDMA power splitter
Access node SNI
dedicated λ1 pair
ONT (Fixed Optics) ONT Bitrate 1
Feeder Fiber
OLT
1 to N λs on single fiber
dedicated λ2 pair
TDMA Wavelength selection here
* “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
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power splitter
ONT Bitrate 2
ONT (Fixed Optics)
Colorless ONTs: Transmitter and Receiver front-end filter characteristics are wavelength adaptable
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2009.8
P19
Today’s PON Systems • TDM-PONs Rule: The vast majority of PON systems deployed today are TDM-based PON systems (i.e., BPON, 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 http://fttwho.blog.sohu.com
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2009.8
P20
TDM PON Architecture and Technologies 20 km Maximum Reach 20 km ONU differential range
OLT BPON
TXR
•Typically: 622 Mbps/155 Mbps (down/up)
Max 32 way split (may be cascaded)
B-PON
Fiber splitter
• Typically: 2488/1244 Mbps GPON
• GFP-like transports (Ethernet, and/or TDM)
G-PON
Max 64 way split [constrained by PMD attenuation limits]
Fiber splitter
ITU-T G.984.x
EPON
• 1250 Mbps/1250 Mbps [~850 Mbps effective payload rate])
TXR
ONT
•ATM-based transport ITU-T G.983.x
TXR
LU #1
Max 32 way split (16-way specified in standard)
LU #N, N ≤32
LU #1
ONT LU #N, N ≤64
LU #1
ONT
• Ethernet-based transport
E-PON
Fiber splitter
1000BASE-PX20 per IEEE 802.3ah
LU #N, N ≤32
Network optical transceiver (TXR) shared by “N” subscribers OLT implementations may not necessarily support all PON technologies indicated
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2009.8
P21
x-PON Technology Time Line FSAN GPON CTS
1995
‘98
‘99
FSAN BPON founded (ITU G.983.1)
published
2000
‘01
BPON IEEE OMCI EPON (G.983.2) begins published
‘02
‘03
FSAN BPON begins OMCI GPON (G.983.2) Revised
BPON Completed: April 2000
‘04
‘05
GPON TC (G.984.3) published
FSAN begins NG-PON
GPON OMCI (G.984.4) published
‘06
7th GPON Interop Event
‘09
‘07 ‘08
1st GPON G.984.5 Interop Event published IEEE begins 10GEPON
IEEE 802.3ah (EPON) published
G.984.1, G.984.3 G.984.4 Rev2 published G.984.2 amd2, G.984.6 published
EPON Completed: June 2004
BPON 1st Interop Event: March 2004
EPON 1st Interop Event: Jan 2006
BPON 1 wide-scale deployment: May 2004 st
EPON 1st wide-scale deployment: 2005
GPON Completed: June 2004 GPON 1st Interop Event: Jan 2006 GPON 1st wide-scale deployment: 4Q 2007
10G-EPON Study started: 2007 NG-PON Study started: 2008
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2009.8
P22
EPON - Downsteam
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2009.8
P23
EPON - Upstream
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2009.8
P24
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 http://fttwho.blog.sohu.com
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2009.8
P25
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
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2009.8
P26
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
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2009.8
P27
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
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2009.8
P28
GPON Frame Structure • • •
Frame size fixed at 125 µs Supports ATM and GEM payload within the same frame PCBd: – Synchronization – DS OAM channel – Upstream bandwidth map (one byte granularity) – Downstream structure
•
DOWNSTREAM FRAME
UPSTREAM FRAME
PLOu: – Synchronization for the new transmitter
•
PLOAMu: – US OAM channel
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2009.8
P29
Overview • Why PON • PON Architecture & Applications • PON Technologies • Next Generation
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2009.8
P30
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
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2009.8
P31
10G-EPON • Two modes: – 10G downstream, 1G upstream – 10G downstream, 10G upstream
• Back compliant with current EPON standard
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2009.8
P32
NG-PON • •
Still in researching phase Two proposals: – NG-PON1 (2009 – 2012) : ITU G.987 – NG-PON2(2012-2015)
•
Wavelength
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2009.8
P33
WDM-PON •
Advantages: – – –
•
Disadvantages: – – –
•
High bandwidth Protocol/data rate transparency High Scurity Inefficiency in the bandwidth utilization Difficult in the wavelength tuning => colorless ONU Difficult in the cascaded topology
In researching phase
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2009.8
P34
RFoG (RFPON)
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2009.8
P35
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2009.8
P36