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