Standardization of
Broadband Optical Access
Network
June 20, 2007
NTT Access Network Service Systems Laboratories
Kenji Nakanishi
nakanisi@ansl.ntt.co.jp
1
(C)2007 NTT
NTT Access Network Service Systems Laboratories
1. International standardization bodies
2. Standardized PON systems
3. B-PON: ITU-T G.983 series
4. G-PON: ITU-T G.984 series
5. E-PON: IEEE802.3EFM
6. Other optical access systems
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
Aim of international standardization
Unified
Unifiedinternational
internationalstandardization,
standardization,
such
suchas
as ITU-T
ITU-TRecommendations
Recommendations
Multi-operator
common spec.
Multi-vendor
inter-operability
For operators
For vendors
Operators
Operators can
can purchase
purchase
devices
devices from
from any
any vendors
vendors
Vendors
Vendors can
can sell
sell devices
devices to
to
any
any operators
operators
>>Reducing
Reducingdevelopment
development risk
risk
>>Reducing
Reducinginvestment
investment
Cost
Cost reduction
reduction in
in worldwide
worldwide scale
scale
-Sharing development resources (Launched with small capital)
-Globalizing the market (Low-cost and matured technology)
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
International standardization bodies
Public organizations
Private organizations
With
secretariat
United
Nations
ITU
ITU-D
ITU-R
ITU-T
ATM-F
Liaison
TTC
ETSI
Japan
Europe
TMF
DSL-F
Liaison
ITU Telecommunication
standardization sector
Liaison
IETF
IEEE
(International Telecommunication Union)
Without
secretariat
Cooperation
Liaison
ANSI (T1)
FSAN
U.S.
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
Activity of ITU-D
- ITU-D aims at achieving the sector member's objectives through access to
infrastructure and information and communication services.
- The detail is shown at http://www.itu.int/net/ITU-D/index.aspx
Focusing issues on ITU-D
-Partnership Portal
Help connect the unconnected
-Emergency Telecommunications
Telecommunications provide the necessary medium and link to mitigate disasters
irrespective of their nature.
-The ICT-eye website
A one stop shop for ICT information
-Cyber-security
Building confidence and security in the use of ICTs
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
International standardization bodies
Public organizations
Private organizations
With
secretariat
United
Nations
ITU
ITU-D
ITU-R
ITU-T
ATM-F
Liaison
TTC
ETSI
Japan
Europe
TMF
DSL-F
Liaison
ITU Telecommunication
standardization sector
Liaison
IETF
IEEE
(International Telecommunication Union)
Without
secretariat
Cooperation
Liaison
ANSI (T1)
FSAN
U.S.
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
Organization related to PON standardization
ATM-F
IEEE
802.3.EFM
E-PON
Liaison
ITU-T
SG4 (Q10)
TMN
OSS-IF
Liaison
ETSI
Liaison
SG15 (Q2)
Optical access
Liaison
SG15(Q6)
CWDM
SG9 (Q12)
Video signal
B-PON
G-PON
Contributions
FSAN
OAN-WG
(Optical Access
Network)
7
(18 operators
+36 vendors)
(C)2007 NTT
NTT Access Network Service Systems Laboratories
FSAN Members
18 Operators
DTAG
BT
Kuwait
MOC
KT
NTT
Chunghwa
Bharat
FT/CNET
Telus
Bell Canada
Embarq
SingTel
TI
SaskTel
Telstra
Verizon
Qwest
AT&T
36 Vendors
Adtran
Alcatel-Lucent
Alphion AMCC
BroadLight
Conexant
ECI Telecom
Ericsson FlexLight
Huawei Iamba
Infineon iPhotonics/TXP
LG Electronics
LS Cable Motorola NEC
Nortel
Novera Optics
OKI
PMC Sierra
Samsung Siemens Tellabs Terawave
Calix
Cambridge
Freescale Fujitsu Hitachi
Maxim/Dallas
Mitsubishi
Optical Zonu
Vitesse Zarlink ZTE
6 Observers
ETRI
ICL/ITRI
KTL
NTS
NTT-AT Telcordia
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
1. International standardization bodies
2. Standardized PON systems
3. B-PON: ITU-T G.983 series
4. G-PON: ITU-T G.984 series
5. E-PON: IEEE802.3EFM
6. Other optical access systems
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
PON configuration outline
- PON (Passive Optical Network) is the most popular solution for
optical broadband access systems.
ODN
UNI
ONT
UNI
NT
UNI
DSL
Optical Fiber
SNI
ONU
OLT
Optical Splitter
Core /
Metro
Network
ONT
OLT (Optical Line Termination): Center equipment of PON
ONT (Optical Network Termination): User side equipment of PON for FTTH
ONU (Optical Network Unit): User side equipment of PON for FTTC
ODN (Optical Distribution Network): Transmission network between OLT and ONTs/ONUs
UNI: User Network Interface
SNI: Service Node Interface
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NTT Access Network Service Systems Laboratories
Standardization bodies for PONs
- Three PONs are standardized internationally by ITU-T and IEEE
PON
Outline
155~622Mb/s ATM cells
Broadband PON Asymmetric for up/down
G-PON
GEM frame for 155~2488Mb/s
B-PON
Gigabit-capable
PON
IEEE E-PON
Ethernet PON
E-PON
Asymmetric for up/down
1250Mb/s Ethernet frame
Same bandwidth for up/down
100~600Mb/s Ethernet frame
Standardization
bodies
ITU-T
FSAN
ITU-T
FSAN
IEEE802.3EFM
N.A.
Note: IEEE E-PON is called GE-PON in Japan.
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NTT Access Network Service Systems Laboratories
Schematics of PON frames
- B-PON divides any signals into ATM cells.
- G-PON packs each signal to a GEM frame whose length is variable. GTC frames
includes GEM frames and is synchronized to 8kHz clock.
- E-PON transmits Ethernet information by Ethernet frames.
B-PON
Ethernet
ATM cells
TDM leased line
POTS
G-PON
TDM leased line
ONT
POTS
TDM leased line
OLT
ONT
Ethernet
Ethernet
GTC frame
GEM frame
125usec
POTS
Ethernet
TDM leased line
OLT
POTS
GEM: G-PON Encapsulation Method GTC: G-PON Transmission Convergence
E-PON (IEEE)
Ethernet
Ethernet
Ethernet frame
ONT
OLT
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NTT Access Network Service Systems Laboratories
Comparison between B/G/E-PON
Items
B-PON
G-PON
IEEE E-PON
Bit rate
Up & Down：155, 622 Mbit/s,
Down only：1.24 Gbit/s
Up & Down：1.24, 2.48 Gb/s
Up only：155, 622 Mbit/s
Up and Down：1.25Gb/s
（1Gb/s after decoding)
Distance
Max. 20 km
Max. 60km
Max. 20ｋｍ
Loss budget 10-25 / 10-28 /15-30 dB
5-20 / 10-25 / 13-28/
15-30 dB
5-21 / 10-26 dB
Branches
Max. 64
Max. 254
Max. over 16
PON
header for
upstream
Guard : 4 bits
Preamble : 12 bits
Delimiter : 8 bits
Independent on bit rate
Guard : 25.7ns
Preamble : 35.4ns
Delimiter : 16.1ns
Example for 1.24 Gb/s
Laser on / off : 512ns
AGC, CDR setting : 400ns
Cipher
Churn or AES (Down)
AES (Down)
Option
Protocol
ATM Cell
GEM frame
Ethernet frame
DBA
Based on G.983.4
Based on G.984.3
Option
Services
Full services
(Ethernet, TDM, POTS)
Full services
(Ethernet, TDM, POTS)
Ethernet services
N.A.
FEC (Optional)
FEC (Optional)
Error
Correction
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NTT Access Network Service Systems Laboratories
Relation between ITU-T and IEEE in PON
ITU-T Q.2/SG15
IEEE
802.3EFM
Liaison relationship
IEEE
E-PON
G-PON
(FSAN)
GPM
GTC
GSR
Common specifications
on optical devices
PMD
sub track
-Optical power level
-Downstream wavelength arrangement
-etc.
P-MP
sub track
Operator's requirements
operators, vendors
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
1. International standardization bodies
2. Standardized PON systems
3. B-PON: ITU-T G.983 series
4. G-PON: ITU-T G.984 series
5. E-PON: IEEE802.3EFM
6. Other optical access systems
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
B-PON Recommendations (G. 983 series)
No.
Outline
Approval date
G.983.1
Physical interface regulation between OLT-ONT
A new ODN class B+ is defined.
G.983.2
Regulation on OLT-ONT management control interface
(OMCI) Revision upon and clerical errors supplement.
Oct. 1998
Jan.2005 Revision
May 2005 Amd1
Apr. 2000
May 2005 Revision
G.983.3
Regulation of wavelength arrangement on multiplex B-PON
and video signals
Apr. 2001
Jul. 2002 Amd1
G.983.4
Regulation of Dynamic Bandwidth Assignment (DBA) on
upstream signals
Dec. 2001
G.983.5
Regulation on survivability (SUR) between OLT-ONT
Jan. 2002
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NTT Access Network Service Systems Laboratories
Example of 3 wave multiplex on B-PON
The WDM filter for video signal multiplexing is added between OLT-ONT.
UNI
User
terminal
ONT
User
terminal
ONT
User
terminal
ONT
1490nm
OLT
Optical splitter
(max 32 branches)
V-ONT
Video
terminal
1555nm
1260
1300
WDM filter
(1490/1555)
SDH
ATM
Ether
MPLS Etc.
V-OLT
1555nm
source of video
transmission
Future use Downstream Digital Use Future use
(1360-1480) (1480-1500) (1539-1565) (FFS)
Upstream
(1260-1360)
1200
SNI
1310nm
1360
1480
1500 Video Use
1400
(1550-1560)
17
1600
Wavelength (nm)
(C)2007 NTT
NTT Access Network Service Systems Laboratories
DBA function (G. 983.4)
-It is an important issue to keep fairness among the users.
-OLT can allocate downstream bandwidth directly, and manage upstream
bandwidth using DBA.
ONT-A
Dynamic bandwidth
assignment
ONT-B
OLT
ONT-C
ONT-D
Shared
bandwidth
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Occupied
bandwidth
(C)2007 NTT
NTT Access Network Service Systems Laboratories
1. International standardization bodies
2. Standardized PON systems
3. B-PON: ITU-T G.983 series
4. G-PON: ITU-T G.984 series
5. E-PON: IEEE802.3EFM
6. Other optical access systems
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
From B-PON to the gigabit class PONs
Issues on B-PON
-Bandwidth shortage on accommodating GbE or IP-TV in UNI.
-AAL5 accommodate Ethernet packets inefficiently.
-High cost of interface card because of un-spread of the full
specification ATM
-Reduction on role of ATM in core system
Expectation for gigabit class PON which has a new frame
FSAN&ITU-T: Aim to accommodate full service by using a generic frame.
 G-PON
IEEE802.3EFM: Aim to cost reduction by using Ether frame.
E-PON
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
B-PON and G-PON Recommendations
G-PON completes its specifications as useful as B-PON
B-PON Recommendations
G.983.1（Basic）
G.983.2（OMCI）
G.983.3（ Wavelength
）
allocation
G.983.4（DBA）
G.983.5（SUR）
G-PON Recommendations
G.984.1（requirements）
G.984.2（Physical layer）
G.984.3（TC layer）
G.984.4（OMCI）
G.984.5 (Enhancement band)
Solid lines show approved Recommendations in G-PON
Broken lines show planned Recommendations in G-PON
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NTT Access Network Service Systems Laboratories
G-PON Recommendations
- Making G.984 series recommendations has been completed.
- ITU-T and FSAN discuss the modifications of G.984 series for the better interoperability and the easier implementation.
No.
Outline
G.984.1 G-PON Service requirements
G.984.2
G.984.3
G.984.4
G.984.5
Approved
Mar. 2003
Mar. 2003
G-PON Interface between OLT-ONT
physical layer specifications
Feb. 2006 Amd1
G-PON Interface between OLT-ONT TC Dec. 2003
Mar. 2006 Amd2
layer specifications
Jun. 2004
G-PON ONT management control
Mar. 2006 Amd2
interface regulation
Jun. 2007(consent)
Enhancement band of G-PON
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NTT Access Network Service Systems Laboratories
Physical layer specifications (G.984.2)
Items
Bit rate
Specifications
1.244 Gbit/s and 2.488 Gbit/s up/down
155.52 Mbit/s and 622.04 Mbit/s only for upstream.
Error rate: better than 1E-10
Under 10km : FP-LD is used without error correction by FEC.
Correction of errors
Under 20km : after adding the error correction by FEC,
by fiber dispersion
DFB-LD or FP-LD is used.
optical device
LD+PIN (APD is also available)
overhead of
upstream signal
4Bytes (155.52Mbit/s), 8Bytes (622.08Mbit/s)
12Bytes (1.244Gbit/s), 24Bytes (2.488Gbit/s)
ODN Classes
(Optical Loss between
OLT and ONT)
Class A: 5 – 20dB
Class B: 10 – 25dB
Class C: 15 – 30dB
Class B+: 13 – 28dB
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NTT Access Network Service Systems Laboratories
Service accommodation method (G. 984.3)
Other services
ATM Service
5th
layer
And
more
ATM
T1/E1
TDM
POTS
Data
Video
VoIP
4th
layer
3rd
layer
TCP+UDP etc.
IP
Ethernet
2nd
layer
ATM frame
GEM frame
G.7041 / T1X1.5 based
G.983 base
GTC frame
1st
layer
PON-PHY
GEM : Gigabit Encapsulation Method.
Based on Generic frame defined in G. 7041.
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NTT Access Network Service Systems Laboratories
Enhancement band (G. 984.5)
- 3 enhancement bands are proposed for a next optical access systems. But
Option1 is TBD, and Option3 has been used for RF video distribution services.
- Upstream band could be narrower using DFB-LD.
G-PON upstream signal for DFB-LD
1290-1330nm
Enhancement
Band Option1
Upstream
Band
1260
Basic
Band
Enhancement
Band Option2
Wavelength: TBD
1300
1360
1480
1400
1500
1620
1600
1530
Enhancement
Band Option3
G-PON upstream signal for FP-LD
1260-1360nm
1480-1500nm
G-PON downstream signal
25
1550-1560nm
RF video signal
(C)2007 NTT
NTT Access Network Service Systems Laboratories
1. International standardization bodies
2. Standardized PON systems
3. B-PON: ITU-T G.983 series
4. G-PON: ITU-T G.984 series
5. E-PON: IEEE802.3EFM
6. Other optical access systems
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
Scope of IEEE E-PON standard
E-PON is one of Ethernet interface series.
E-PON System consists of both std. and out of scope specifications.
Standardized specifications
Basic functionalities for
transmission
IEEE802.1AE
Need more time for
specifying technical issues
E-PON
System
Out of scope specifications
System functionalities for carrier
service provisioning
Ops IF
DBA/QoS
Link Security
IEEE802.3ah(EFM)
Technical specifications are
matured.
Standard will complete June
2004.
OAM (Optional)
MAC/MPCP
PHY
27
Sys.
Cntrl.
• Operation system interface
OAM&P, Test, DB-IF….
• DBA (Dynamic Bandwidth Allocation)
Bandwidth control
• Authentication
User/ONU registration/Deregistration
• System OS
Private MIB, Alarm process……
• System configurations
Fault recovery, powering, cooling….
And more ….
(C)2007 NTT
NTT Access Network Service Systems Laboratories
PHY layer specifications in E-PON
- PHY layer consists of three sub-layers, PMD, PMA and PCS
- PMD is newly defined for GE-PON, but PMA and PCS are expanded
from the other Giga-bit Ethernet specifications
PCS
Reconciliation
GMII
(Gigabit Media Independent Interface)
PCS (Physical Coding Sublayer)
PMA
PMA (Physical Media Attachment)
Reconciliation
To MAC layer
GMII
PMD
MDI
ONU
Optical fiber
PMD (Physical Medium Dependent)
MDI
(Medium Dependent Interface)
Optical splitter
OLT
PCS: 8B10B codec (Mandatory), Forward Error Correction (FEC; Optional)
PMA: Bit synchronization of burst signals, Group synchronization with 10bit
PMD: Power, wavelength and eye pattern of optical signals, ON/OFF time of LD
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
MAC layer specifications in E-PON
MAC layer includes MAC sub-layer which is common in all Ethernet
interface, and Multi-Point MAC Control sub-layer which is specified for
GE-PON.
“Instance” means Multi-Point MAC Control Instance.
OAM
Multi-Point
Transmission
Control
Multi-Point MAC
Control Instance
MAC
Reconciliation
PHY layer
ONU
OAM
OAM
Instance
MAC
OAM
Instance Instance
MAC
MAC
Reconciliation
Optical fiber
Optical splitter
PHY layer
OLT
-Multi-point MAC control sub-layer consists of Multi-Point Transmission Control and
Multi-Point MAC Control Instance.
-The instance and MAC manage the GE-PON system as a point-to-point system.
-The control selects an active instance for each Ethernet frame.
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
OAM specifications in E-PON
- OAM premises a logical point-to-point configuration which is
common in all Ethernet specifications.
- OAM does not provide any functions that are specified only for GEPON.
- OAM is optional in Ethernet specifications.
MAC clients
OAM clients
８02.3 OAM client
Service Interface
８02.3 MAC data
Service Interface
OAM layer
８02.3 MAC data
Service Interface
Multi-Point MAC Control
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
1. International standardization bodies
2. Standardized PON systems
3. B-PON: ITU-T G.983 series
4. G-PON: ITU-T G.984 series
5. E-PON: IEEE802.3EFM
6. Other optical access systems
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
Differences in MC specifications
Media Converter (MC) is another cost effective solution when the
user density is low enough.
ITU-T and IEEE make different standards for MC.
[Layer structure] Differences in MCs
Higher Layer
IEEE OAM
MAC CONTROL
MAC
RS
MII
ITU-T OAM
PCS
PMA
PMD
The
The termination
termination of
of
the
the MAC
MAC frame
frame is
is
required.
required.
from layer structure view point
◆ Bridge type MC
(100BASE-BX)
BRIDGE
MAC
MAC
PHY
PHY
◆ Repeater type MC
(G. 985)
Optical fiber
The
The termination
termination of
of
the
MAC
frame
is
the MAC frame is
unnecessary.
unnecessary.
Repeater
PHY
Medium
32
PHY
Optical fiber
(C)2007 NTT
NTT Access Network Service Systems Laboratories
Standardization trend of WDM systems
1 Economization of CWDM system (G.695)
For supplying various services in metro / access system,
economical CWDM system is examined.
- 20nm interval (1271-1611nm) wavelength grid- approved G.694.2.
- For application services SDH and GbE are planned.
-Subdivision of interface specified points, and multiplex numbers 4-16 are
under discussion.
2 DWDM system application to the metro / access system (G.698.1)
DWDM system is mainly used in core system, and applying it to
metro / access system is examined by specializing for short
distance with low cost
-Wavelength grid is 100GHz, 50 GHz, 25 GHz, 12.5 GHz-G.694.
-Focus functions by abbreviating 3R and such (clarify services applied)
-Subdivide interface specified point aiming at multi vendors
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
Conclusions
PON is the cost effective solution for broadband optical access
network.
International standards of PON have been established in ITU-T
(B-PON and G-PON) and IEEE (E-PON).
The 3 PONs have different PON frames, but their physical layer
specifications are nearly same.
Inter-operability and common specifications are the next issue
for deploying broadband optical access systems
WDM access systems are discussed in ITU-T and FSAN
towards the future standards.
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(C)2007 NTT
NTT Access Network Service Systems Laboratories
Thank you
The beckoning cat, Maneki Neko,
brings Luck.
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(C)2007 NTT
NTT Access Network Service Systems Laboratories