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GPON 光學網路上動態頻寬配 置機制的設計 指導教授:吳和庭老師 Speaker...
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Transcript of GPON 光學網路上動態頻寬配 置機制的設計 指導教授:吳和庭老師 Speaker...
GPON 光學網路上動態頻寬配置機制的設計
指導教授:吳和庭老師
Speaker :蘇泳蒼
1
OutlineIntroductionGPON DBASimulationFuture workReferences
2
Introduction
3
ONU 1
ONU 2
ONU N
OLT......
Introduction在 GPON ,上傳頻寬分配是用 T-CONT
(transmission container) 來做分配的, T-CONT是一群連接,且每一個 T-CONT 都會對到一個Alloc-ID 。
OLT 會利用 BWmap (upstream bandwidth map) 來指示 ONU 何時可以傳送資料。
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ITU-T dynamic bandwidth assignment每個 Alloc-ID 都會有 traffic descriptor 來描述頻
寬分配的參數
RF : Fixed bandwidth
RA : Assured bandwidth
RM : Maximum bandwidth
χAB : Ternary eligibility indicator for additional bandwidth assignment {None, NA, BE}
iAB
iM
iA
iF
i RRRD ,,,
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ITU-T dynamic bandwidth assignment分配給 Alloc-ID 的頻寬可以分成兩個部分,分別是
guaranteed 和 additionalχAB = NA
χAB = BE
RG : Guaranteed bandwidth
RNA : Non-assured bandwidth
RBE : Best-effort bandwidth
)()()( tRtRtR iNA
iG
i
)()()( tRtRtR iBE
iG
i
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ITU-T dynamic bandwidth assignment Guaranteed bandwidth 的分配方式是
RL : Offered traffic load
分配完 guaranteed bandwidth 之後剩下的頻寬,就分配給 non-assured bandwidth
對於任兩個要求沒被滿足的 Alloc-ID ,分配方式如下
)(;max;min)( tRRRRtR iL
iF
iA
iF
iG
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jA
jF
jNA
iA
iF
iNA
RR
tR
RR
tR
)()(
ITU-T dynamic bandwidth assignment 分配完 non-assured bandwidth 之後剩下的頻寬,接
著分配給 Best-effort bandwidth 對於任兩個要求沒被滿足的 Alloc-ID ,分配方式如下
)(
)(
)(
)(jA
jF
jM
jBE
iA
iF
iM
iBE
RRR
tR
RRR
tR
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ITU-T dynamic bandwidth assignment T-CONT type 1 is suitable for carrying fixed-rate
traffic which is sensitive to delay and jitter. T-CONT type 2 is suitable for carrying on-off type
traffic with well-defined rate bound which does not have strict delay and jitter requirements.
T-CONT type 3 is suitable for carrying variable-rate bursty traffic which requires average rate guarantee.
T-CONT type 4 is suitable for carrying variable-rate bursty traffic which does not exhibit delay sensitivity.
T-CONT type 5 is a consolidation of other T-CONT types which can be applied to most general traffic flows.
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ITU-T dynamic bandwidth assignment
Traffic descriptorcomponen
t
Type 1 Type 2 Type 3 Type 4 Type 5
Fixed BW RF RF
Assured BW RA RA RA
Maximum BW
RM = RF RM = RA RM > RA RM
RM ≥ RF + RA
Additional BW
eligibilityNone None NA BE Any
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Immediate allocation with colorless grant algorithm
T-CONT type Bandwidth Service parameters
1 Fixed SImax , ABmin
2 Assured SImax , ABmin
3Assured SImax , ABmin
Surplus SImin , ABsur
4For polling SImax , ABmin
Surplus SImin , ABsur
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Immediate allocation with colorless grant algorithm
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配置頻寬Va(j) > 0
SImax_timer(j) = 1
SImax_timer(j)=SImax(j)
Va(j) = ABmin(j)
SImax_timer(j)--
是
否
是
否
Immediate allocation with colorless grant algorithm
配置頻寬Vs(j) > 0
SImin_timer(j) = 1
SImin_timer(j)=SImin(j)
Vs(j) = ABsur(j)
SImin_timer(j)--
是
否
是
否
Immediate allocation with colorless grant algorithm從 Alloc-ID 的頻寬需求、 Va 、剩下的頻寬中取最
小值,然後將此值作為分配給 Alloc-ID 的頻寬
將 Va 減掉分配給 Alloc-ID 的頻寬大小
Immediate allocation with colorless grant algorithm若還有多餘的頻寬,則將多餘的頻寬平均分配給各
各 ONU 的 T-CONT type 5ONU 將會依 T-CONT type2 、 type3 、 type4 的
順序,來傳送 queue 裡的資料,直到頻寬被用盡或是 queue 裡都沒資料
Simulation模擬工具: OMNeT++T-CONT type 1 traffic 類型:每 125 us 來 50
bytes packetT-CONT type 2 、 3 、 4 traffic 類型: PoissonT-CONT type 2 、 3 、 4 traffic 比例:為扣除 T-
CONT type 1 之後,平均分配Packet size : 64 ~ 1518 bytes模擬時間: 10 sec
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Simulation
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0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.0001
0.0002
0.0003
0.0004
0.0005
0.0006
0.0007
0.0008
0.0009
IACG type1IACG type2IACG type3IACG type4ITU-T type1ITU-T type2ITU-T type3ITU-T type4
Traffic load
Dela
y (
s)
Simulation
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0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.2
0.4
0.6
0.8
1
1.2
IACGITU-T
Traffic load
Uti
lizati
on
Future work研究在其他 traffic 的狀況下, DBA 的運作情形探討在 long reach 的情況下, DBA 是否能運作良
好設計更有效率的 DBA
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References ITU-T Rec. G.984.1, “Gigabit-capable Passive Optical
Networks (G-PON): General characteristics,” 2008. ITU-T Rec. G.984.3, “Gigabit-capable Passive Optical
Networks (G-PON): Transmission convergence layer specification,” 2008.
M.S. Han, H.Y., B.Y. Yoon, B. Kim and J.S. Koh, “Efficient dynamic bandwidth allocation for FSAN-compliant GPON,” Journal of Optical Networking, Vol. 7, Issue 8, 2008, pp. 783-795.
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Q&A
Thanks for you attention
21