指導教授 : 吳和庭 博士 研究生： 簡睿毅 日期 : 2005 / 7 / 15

乙太被動式光學網路上能支援多媒體服務之動態頻寬配置機制Dynamic Bandwidth Allocation Mechanisms for Multimedia Services on EPON

指導教授 : 吳和庭 博士研究生：簡睿毅日期 : 2005 / 7 / 15

Outline

Background Passive Optical Network (PON) Ethernet Passive Optical Network (EPON) Multi-Point Control Protocol (MPCP)

Motivation Dynamic Bandwidth Allocation Scheme

IPACT & DBAM DBA with QoS

Simulation Result Conclusion & Future Work

Background

The first mile still remains the bottleneck between high-capacity Local Area Networks (LANs) and the backbone network

A new technology is required to an end-user over a single network Inexpensive , Simple , Scalable Delivering bundled voice , data , video services

Passive Optical Network ( PON )

A point-to-multipoint optical network Two primary types of PON technologies

ATM PONEPON

PON Topology

Ethernet Passive Optical Network

EPON started to be standardized by IEEE

802.3ah EFM since 2001(2004 July done) Ethernet is a ubiquitous technology

Deployed widely in LAN, MAN and WAN

Ethernet is more attractive to PON than ATM High speed - up to 10 Gigabit/s Lower cost Easier interoperability

EPON Architecture

Features of EPON

All data packets carried in EPON are encap

sulated in Ethernet frames Broadcasting in the downstream direction fr

om the OLT to ONUs Sharing the upstream channel capacity amo

ng ONUs

That is the problem !

Multi-Point Control Protocol

The Multi-Point Control Protocol (MPCP) specifies a control mechanism between a Master unit and Slaves units connected to a Point-to-Multi-Point (P2MP) segment to allow efficient transmission of data

MPCP is implemented in MAC Control layer MPCP uses five MAC Control messages

GATE, REPORT, REGISTER_REQ, REGISTER, and REGISTER_ACK

Motivation

A dynamic bandwidth allocation scheme with a credit mechanism which can support QoS service and reduce packet delay

Dynamic Bandwidth Allocation Scheme

IPACT Interleaved Polling with Adaptive Cycle Time

DBAM Dynamic Bandwidth Allocation with Multiple Services

DBA with QoS Dynamic Bandwidth Allocation with QoS

IPACT Operation Step (1/4)

IPACT Operation Step (2/4)

IPACT Operation Step (3/4)

IPACT Operation Step (4/4)

Definition (1)

EF Expedited Forwarding ， High Priority

AF Assured Forwarding ， Medium Priority

BE Best Effort ， Low Priority

Definition (2)

The maximum bandwidth parameter of a specific class of traffic is determined by the SLA between the

end user and service provider

the amount of data queued up in the buffer

is the requested bandwidth for class c traffic

the estimation credit

EF AF BEi i i iS S S S

EF AF BEi i i iR R R R

(1 )* , { , , }c ci iC R c EF AF BE EF AF BE

i i i iC C C C

, ,/i in waiting n cycleT T

ciC

Waiting Time & Cycle Time

DBAM Operation

EF AF BEi i i iC C C C

(1 )* , { , , }c ci iC R c EF AF BE

iC m in{ , }i i iB C S

, 1 , 1min{ , }, { , }c c ci n i n iB C S c EF AF

, 1 , 1 , 1 , 1BE EF AFi n i n i n i nB B B B

DBAM Case

, 1 , 1min{ , }, { , }c c ci n i n iB C S c EF AF

SLA SiEF:20 AF:30 BE:50

Request RiEF:60 AF:20 BE:20

Credit CiEF:70 AF:25 BE:25

EF:20 AF:25

EF:20 AF:25 BE:55, 1 , 1 , 1 , 1

BE EF AFi n i n i n i nB B B B

Assign Bandwidth = 100

min{ , }i i iB C S

Definitions

Actual queue size when transmission start

Finally guarantee bandwidth

EF AF BEi i i iA A A A

iS iR iC

EF AF BEi i i iG G G G

Waiting Time & Cycle Time

DBA with QoS Operation(1/2)

EF AF BEi i i iR R R R

(1 )*c ci iC R min{ , }i iBi C S

Bi

DBA with QoS Operation(2/2)

min{ , }, { , , }c c ci i iG S R c EF AF BE

min{ , , }c c c c c c ci i i i i i iG C G A G S G

min{ , }c c c c ci i i i iG C G A G

max{ , }c c c c ci i i i iG C G A G

DBA with QoS CaseSLA Si

EF:20 AF:30 BE:50

Request RiEF:60 AF:20 BE:20

Credit CiEF:70 AF:25 BE:25

Assign Bandwidth = 100

min{ , }i i iB C SEF:20 AF:20 BE:20

min{ , }, { , , }c c ci i iG S R c EF AF BE

Actual Queue Request AiEF:65 AF:30 BE:25

min{ , ,max{ ,0}}c c c c c ci i i i i iC G A G S G

GiEF:20 AF:20 BE:20

GiEF:20 AF:25 BE:25

min{ , }c c c ci i i iC G A G

GiEF:50 AF:25 BE:25

Request RiEF:60 AF:20 BE:20

DBAM GiEF:20 AF:25 BE:55

Simulation ModelEPON的系統頻寬 1Gbps

ONU個數 16

封包大小 64~1518 Bytes

佇列大小 1 Mbytes

模擬時間 1秒

系統負載 (Normalized Offer Load)

0~2

SLA比例 EF-20% AF-30% BE-50%

封包產生方式 Poisson

Simulated Result (1)

Load: EF-80% AF-10% BE-10%

00.050.1

0.150.2

0.250.3

0 0.5 1 1.5 2

Traffic Load

Ave

rage

EF

Pack

et D

elay

(s)

DBAM

DBA With QoS

IPACT

IPACT with Credit

Simulated Result (2)

Load: EF-80% AF-10% BE-10%

0

0.05

0.1

0.15

0.2

0 0.5 1 1.5 2

Traffic Load

Ave

rage

AF

Pack

et D

elay

(s)

DBAM

DBA With QoS

IPACT

IPACT with Credit

Simulated Result (3)

Load: EF-80% AF-10% BE-10%

0

0.05

0.1

0.15

0.2

0 0.5 1 1.5 2

Traffic Load

Ave

rage

BE

Pack

et D

elay

(s)

DBAM

DBA With QoS

IPACT

IPACT with Credit

Simulated Result (4)

DBA with QoS

00.020.040.060.080.1

0.12

0 0.5 1 1.5 2

Traffic Load

Ave

rage

Pac

ket D

elay

(s)

Load: EF-20% AF-30% BE-50%

Load: EF-80% AF-10% BE-10%

Load: EF-10% AF-80% BE-10%

Load: EF-10% AF-10% BE-80%

Simulated Result (5)

DBAM

0

0.05

0.1

0.15

0.2

0.25

0 0.5 1 1.5 2

Traffic Load

Ave

rage

Pac

ket D

elay

(s)

Load: EF-20% AF-30% BE-50%

Load: EF-80% AF-10% BE-10%

Load: EF-10% AF-80% BE-10%

Load: EF-10% AF-10% BE-80%

Credit Consideration

1, * *( / ), { , , }c c i ci i n waiting i i iC R T dataRate S S c EF AF BE

Simulation Result (1)

Load: EF-80% AF-10% BE-10%

00.050.1

0.150.2

0.250.3

0 0.5 1 1.5 2

Traffic Load

Ave

rage

EF

Pack

et D

elay

(s)

DBAM

Credit_1

Credit_2

Simulation Result (2)

Load: EF-80% AF-10% BE-10%

00.020.040.060.080.1

0.12

0 0.5 1 1.5 2

Traffic Load

Ave

rage

AF

Pack

et D

elay

(s)

DBAM

Credit_1

Credit_2

Simulation Result (3)

Load: EF-80% AF-10% BE-10%

0

0.05

0.1

0.15

0 0.5 1 1.5 2

Traffic Load

Ave

rage

BE

Pack

etD

elay

(s) DBAM

Credit_1

Credit_2

Conclusion & Future Work

Proposed a dynamic bandwidth allocation scheme can support QoS and reduce the packet delay for Ethernet Passive Optical Network

Future Work : Credit consideration