4
PON’s origination
Bandwidth bottleneck between end users and
backbone networks
PON can provide more bandwidth to end users
in a cost-effective way
5
EPON’s advantages
low-cost Ethernet equipment and low cost passive
optical components
lower cost for equipment maintenance
larger bandwidth capacity
longer transmission distance(10~20km)
6
EPON Architecture
point-to-multipoint fiber optical network with no
active elements in the transmission path from
source to destination
7
Operation principle
In an EPON system all data are encapsulated in
Ethernet packets for transmission
ONU)(OLT- direction Downstream
9
Multi-Point Control Protocol(MPCP)
Being developed by the IEEE 802.3ah task force.
This protocol relies on two Ethernet messages : GATE and
REPORT to achieve dynamic bandwidth allocation process
GATE : assign time slot
REPORT : report ONU’s local queues condition
16
Transmission window
OLT use transmission window to notify ONU let ONU
knows that how many data it can upload in a cycle.
Max transmission window size
It’s a threshold that use to forbid ONU upload too
many data in a cycle
17
Transmission window The way to determine the Transmission window size
Limited service
If (request>Transmission window size)
Transmission window size=Max transmission window size
else
Transmission window size=request
Gated service
Transmission window size=request
Fixed service
Transmission window size=Max Transmission window size
18
Offline scheduling
Once OLT collect Report message from all ONUs, then start to send Gate messages to response ONU.
19
Offline scheduling
Partial ONU in two groups High load and light load
Let ONUs which belong the high load group can use excess bandwidth to transmit more data
20
Offline scheduling
Guarantee bandwidth computation
Excess bandwidth assignment
After DBA Bandwidth assignment
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MINiTOTALEXCESSH
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21
Offline scheduling with early allocation scheme
if (Request<=guarantee bandwidth)
Grant bandwidth right away
else
Grant bandwidth after collect all REPORT messages
23
Simulation description
Model1(M1) Offline scheduling mechanism
Model2(M2) Offline scheduling with early allocation scheme
Intra-ONU bandwidth assign methods[1]
Strict Priority Priority queuing(OLT)Central control
24
Simulation parametersONU number 16
Uplink transmission rate 1Gb/sSimulation time 30s
RTT time /transmission distance Uniform(100~200)us /10~20km
Offered network load(ONU’s maximum input traffic rate)
0.08~1.6(Gbps)(100Mb/s)
Maximum cycle time 2ms
Guard time 5us
Packet size P0 : fix at 70 bytesP1 , P2 : Uniform(64~1518) bytes
Traffic type_1 P0 fix at 4.48Mbit/s,P1,P2 : Remain loading*50%
Packet generate method P0 : Constant bit rateP1 , P2 : Poisson distribution
Measurement metrics Delay
Maximum transmission window size 15000 bytes
26
0.08 0.16 0.24 0.32 0.4 0.48 0.56 0.64 0.72 0.8 0.88 0.96 1 1.04 1.12 1.2 1.28 1.36 1.44 1.52 1.6
1.00E-04
1.00E-03
1.00E-02
1.00E-01
1.00E+00
1.00E+01
1.00E+02
M1-PriortyQ
M1-PriorityQ-P0 M1-Priority-P1 M1-PriorityQ-P2
Offered network load (Gbps)
Delay(Second)
27
0.08 0.16 0.24 0.32 0.4 0.48 0.56 0.64 0.72 0.8 0.88 0.96 1 1.04 1.12 1.2 1.28 1.36 1.44 1.52 1.6
1E-04
1E-03
1E-02
1E-01
1E+00
1E+01
1E+02
IPACT-limit-PriorityQ
IPACT-limit-PriorityQ-P0 IPACT-limit-PriorityQ-P1 IPACT-limit-PriorityQ-P2
Offered network load (Gbps)
Delay (Second)
28
0.08 0.16 0.24 0.32 0.4 0.48 0.56 0.64 0.72 0.8 0.88 0.96 1 1.04 1.12 1.2 1.28 1.36 1.44 1.52 1.60.0E+00
5.0E-04
1.0E-03
1.5E-03
2.0E-03
2.5E-03
3.0E-03
Compare Online to Offine-P0 data
M1-PriorityQ-P0 IPACT-limited-PriorityQ-P0
Offered network load (Gbps)
Delay(Second)
29
0.08 0.16 0.24 0.32 0.4 0.48 0.56 0.64 0.72 0.8 0.88 0.96 1 1.04 1.12 1.2 1.28 1.36 1.44 1.52 1.60.0E+00
5.0E-04
1.0E-03
1.5E-03
2.0E-03
2.5E-03
3.0E-03
3.5E-03
4.0E-03
Compare Online to Offine-P1 data
M1-PriorityQ-P1 IPACT-limited-PriorityQ-P1
Offered network load (Gbps)
Delay(Second)
30
0.08 0.16 0.24 0.32 0.4 0.48 0.56 0.64 0.72 0.8 0.88 0.96 1 1.04 1.12 1.2 1.28 1.36 1.44 1.52 1.6
1E-04
1E-03
1E-02
1E-01
1E+00
1E+01
1E+02
Compare Online to Offine-P2 data
M1-PriorityQ-P2 IPACT-limited-PriorityQ-P2
Offered network load (Gbps)
Delay(Second)
31
0.08 0.16 0.24 0.32 0.4 0.48 0.56 0.64 0.72 0.8 0.88 0.96 1 1.04 1.12 1.2 1.28 1.36 1.44 1.52 1.60.0E+00
5.0E-04
1.0E-03
1.5E-03
2.0E-03
2.5E-03
3.0E-03
3.5E-03
M1 with different Intra-ONU bandwidth assign methods-P0
Strict Priority-P0 PriorityQ-P0 Central control-P0
Offered network load (Gbps)
Delay(Second)
32
0.08 0.16 0.24 0.32 0.4 0.48 0.56 0.64 0.72 0.8 0.88 0.96 1 1.04 1.12 1.2 1.28 1.36 1.44 1.52 1.60.0E+00
5.0E-04
1.0E-03
1.5E-03
2.0E-03
2.5E-03
3.0E-03
3.5E-03
4.0E-03
4.5E-03
M1 with different Intra-ONU bandwidth assign methods-P1
Strict Priority-P1 PriorityQ-P1 Central control-P1
Offered network load (Gbps)
Delay(Second)
33
0.08 0.16 0.24 0.32 0.4 0.48 0.56 0.64 0.72 0.8 0.88 0.96 1 1.04 1.12 1.2 1.28 1.36 1.44 1.52 1.6
1E-04
1E-03
1E-02
1E-01
1E+00
1E+01
1E+02
M1 with different Intra-ONU bandwidth assign methods-P1
Strict Priorty-P2 PriorityQ-P2 Cental control-P2
Offered network ;oad (Gbps)
Delay(Second)
34
0.08 0.16 0.24 0.32 0.4 0.48 0.56 0.64 0.72 0.8 0.88 0.96 1 1.04 1.12 1.2 1.28 1.36 1.44 1.52 1.60.0E+00
5.0E-04
1.0E-03
1.5E-03
2.0E-03
2.5E-03
3.0E-03
3.5E-03
4.0E-03
Compare M1 M2-PriorityQ-P0,P1
M1-PriorityQ-P0 M2-PriorityQ-P0 M1-PriorityQ-P1 M2-PriorityQ-P0
Offered network load (Gbps)
Delay(Second)
35
0.08 0.16 0.24 0.32 0.4 0.48 0.56 0.64 0.72 0.8 0.88 0.96 1 1.04 1.12 1.2 1.28 1.36 1.44 1.52 1.6
1E-04
1E-03
1E-02
1E-01
1E+00
1E+01
1E+02Compare M1 M2-PriorityQ-P2
M1-PriorityQ-P2 M2-PriorityQ-P2
Offered network load (Gbps)
Delay(Second)
36
Remaining work
Define a DBA which base on offline scheduling that can well reduce idle time on EPON system.
37
Reference[1] C.M. Assi, Yinghua Ye, Sudhir Dixit, and M.A. Ali, “ Dynamic
bandwidth allocation for quality-of-service over Ethernet
PONs ,”IEEE Journal on Selected Areas in Communications,
vol.21, no.9, pp. 1467-1477, November 2003.
[2] G. Kramer, B. Mukherjee, and G. Pesavento, “Interleaved Polling
with Adaptive Cycle Time (IPACT): A Dynamic Bandwidth
Distribution Scheme in an Optical Access Network,”Photonic
Network Communications, vol. 4, no. 1 pp. 89-107, January 2002.
[3] J. Zheng and H.T. Mouftah, “Media access control for Ethernet
passive optical networks: an overview,”IEEE Communications
Maganize, vol.43, no2 pp.145-150 , February 2005.
[4] G. Kramer, Ethernet Passive Optical Networks, McGraw-Hill
Professional, ISBN: 0071445625, Publication date: March 2005.