Post on 17-Sep-2015
GPON Technology
ZTE University
Contents
GPON Basics
GPON Working Principle
GPON Key Technologies
GPON Technology Standard-G.984 Series
ITU-T G.984.3
Transmission Convergence layer
specification
GTC multiplex structure and protocol
GTC frame structure definition
Specification of the ONU registration
method and various clarifications
DBA specification
Alarms and performance
ITU-T G-984.1/2/3/4
ITU-T G.984.1
GPON general characteristics
Protection switchover requirements
ITU-T G.984.4
ONT management and control
interface(OMCI) specification
OMCI equipment management
architecture
OMCI principle introduction
ITU-T G.984.2
Physical Media Dependent(PMD) layer
specification
Optical interfaces specification for
2.488Gbit/s downstream/1.244 Gbit/s
upstream
Physical layer overhead definition
Service Network
OLT
ONT
ONT
ONT
G.652
Splitter
20km
SNI
Logical reach: 60km
Logical split ratio: 1:128
Line Rate:
155 Mb/s up, 1.25 Gbit/s down
622 Mb/s up, 1.25 Gbit/s down
1.25 Gb/s up, 1.25 Gbit/s down
155Mb/s up, 2.5Gbit/s down
622 Mb/s up, 2.5 Gbit/s down
1.25 Gb/s up, 2.5 Gbit/s down
2.5 Gb/s up, 2.5 Gbit/s down
Downlink wavelength: 1490nm
Uplink wavelength:1310nm,
Third party wavelength:1550nm
NMS
CPN
GPON System Architecture
OLT
Splitter
ONT
CO
OLT(Optical Line Terminal)
Generically placed in the Central Office
ONU(Optical Network Unit)
Generically placed indoor or outdoor, such as on the desk,
dwelling, in the cabinet, etc. kinds of ONUs for different users
ODN(Optical Distribution Network)
Passive network with kinds of components
Distribution Cabinet
Components of GPON System
Full Services Access
Office/Enterprise
splitter
Equipment Room
OLT C300
CO
WDM
IPTV
Phone
ONUHGW
PC
LaptopWIFI
ONU
PCCATV
PhoneFTTH
IPTVCATV
Internet
SS
CBU
FE/GE/E1
NodeB/BTSHandset
Laptop
Mobile Backhaul
Cross-connectionCabinet of Fiber
ONU
DSLAM
PC
Phone
Modem
PC
Phone
PSTN
IPTV
PCPhone
HGW
FTTB
MDU
MDUPhone
PC
PBX
LAN SwitchFTTO
BSC/RNC
FE/GEE1/STM-1
FE/GE/10GE
E1/T1
splitter
Contents
GPON Basics
GPON Working Principle
GPON Key Technologies
GPON Downstream/Upstream Dataflow
GPON Technology Architecture
Protocol Stack for C/M Plane
Protocol Stack for U Plane
The Multiple Service Features for GPON System
GPON Frame Structure
125 s
125 s
Downstream Frame Structure
Upstream Frame Structure
PLOuAllocation
intervalsPLOu Allocation intervals PLOu
Allocation
intervals
ONU Burst ONU Burst ONU Burst
Upstream GTC frame, 125us
GEM Frame Structure
GPON Multiplexing Architecture
ONU
Optical Network Unit
T-CONT
Transmission Container
GEM Port
GEMGPON Encapsulation Method
Ethernet over GEM
Contents
GPON Basics
GPON Working Principle
GPON Key Technologies
GPON DBA
GPON QoS
GPON Protection
GPON Security
How does DBA function?
T-CONT will report the status of its buffers so as to ask for upstream bandwidth
assignment.
OLT will give corresponding bandwidth to each T-CONT based on their buffer status,
and the assignment will be sent to each T-CONT in the downstream GTC stream.
After receiving the bandwidth assignment, ONU will be responsible to give bandwidth
to each queue of each T-CONT.
GPON Bandwidth Types
Fixed bandwidth
After the T-CONT is activated, OLT will give it corresponding time slot regardless
whether or not T-CONT has upstream traffic requirement.
Assured bandwidth
The only difference with fixed bandwidth is that assured bandwidth can be shared .
Non-Assured bandwidth
Only after the assignment of fixed and assured bandwidth can non-assured
bandwidth get its share.
Best-Effort bandwidth
Bandwidth with lowest priority. Only after the assignment of fixed, assured and non-
assured can Best-Effort get its share.
Maximum bandwidth
Regardless what the actual upstream demand is, the assignment bandwidth can
not exceed maximum bandwidth.
Equal to the total of fixed, assured, non-assured and Best Efforts bandwidth.
The priority is: fixed> assured >non-assured>best effort.
T-CONT
T-CONT manages GPON upstream bandwidth assignment
T-CONT contains GEM PORT and report buffer status to related OLT.
T-CONT dynamically receives bandwidth authorization identified by
ALLOC-ID from OLT.
Single T-CONT contains different service level GEM streams.
Single T-CONT provides multiple physical queue and converge to one
logical buffer.
T-CONT is transparent transmission entity, not changing any signal.
OLT grants bandwidth authorization to one T-CONT.
DBA-T-CONT status report describes one T-CONT logical buffer status.
GPON T-CONT Types
Type 1 only consists of fixed bandwidth with defined time slot, suitable for service
such as E1/T1
Type 2 only consists of assured bandwidth (defined bandwidth without defined time-
slot), suitable for services such as VOD.
Type 3 consists of both assured and non-assured bandwidth, suitable for business
customers.
Type 4 only consists Best Efforts Bandwidth, suitable for for Internet Service.
Type 5 is a mixture of Fixed, Assured and Best Efforts bandwidth, which is suitable
for most services.
Contents
GPON Basics
GPON Working Principle
GPON Key Technologies
GPON DBA
GPON QoS
GPON Protection
GPON Security
GPON End-End QoS Upstream
GEM portEthernet port T-CONT
802.1p mapping to GEM port
SP/WRR
Schedule
ONT
GPON MAC Ethernet MAC
SP/WRR
Schedule
Ethernet PORT
Queue 1
Queue 8GPON
PORT
DBA
OLT
Ethernet PORT
Queue 1
Queue 8
For upstream, traffic, with different priority, comes from ONT UNI will be classified by
802.1p and mapped to different GEM port,
GEM port will be connected with specific T-CONT, which is given specific type with
different bandwidth to guarantee the service QoS.
On the OLT, the DBA will adjust the bandwidth of T-CONT dynamically. When traffic is
out of GPON Mac, which will be put into different queue of SNI port according the
mapping of 802.1p to queue. High priority will be put in high queue which will be sent
first out of the port.
GPON End-End QoS Downstream
For downstream, traffic with different priority, comes from SNI, will be classified by 802.1p and mapped into the queue of traffic unit, which is given specific type with different bandwidth to guarantee the service QoS
On the ONT, traffic out of GPON Mac will be mapped to specific queue according to the 802.1p.High priority traffic will be sent out first.
OLTONT
GPON MACEthernet MAC
GPON
PORT
Ethernet PORT
Queue 1
Queue 8
Ethernet PORT
Queue 1
Queue 8
GPON MAC Ethernet MAC
GPON
PORT
Traffic
Unit
Traffic
Unit
Contents
GPON Basics
GPON Working Principle
GPON Key Technologies
GPON DBA
GPON QoS
GPON Protection
GPON Security
Protection of PON-based network
PON LT
OLT
PON LT
ONU/ONT #1
PON LT
Spare fibre
N:1 optical
splitter
ONU/ONT #N
OLT
PON LT
PON LT
N:2 optical
splitter
PON LT (1)
PON LT (0)
ONU/ONT #1
ONU/ONT #N
G.984.1 Duplex GPON system:
Fibre duplex system
G.984.1 Duplex GPON system:
OLT-only duplex system
Protection Mechanism of GPON
Protection of PON-based network
OLT
Double
N:1 optical
splitter
PON LT (1)
PON LT (0)
PON LT (1)
PON LT (0)
PON LT (1)
PON LT (0)
ONU/ONT #1
ONU/ONT #N
G.984.1 Duplex GPON system:
Full duplex system
G.984.1 Duplex GPON system:
Partial duplex system
The Protection of GPON
Contents
GPON Basics
GPON Working Principle
GPON Key Technologies
GPON DBA
GPON QoS
GPON Protection
GPON Security
Encryption of GPON System
Encryption Method:AES-128
Encryption Unit: PORT-ID
Encryption Direction: Downstream
Encryption Key Resource: ONU
Encryption Key Update Request: OLT