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乙太被動式光纖網路之三模式節能機制設計 (The design of three mode based power saving mechanisms in EPON)

Speaker: Shieh-Chieh ChienAdvisor: Dr. Ho-Ting Wu2014/05/26

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Outline PON EPON

TDM & TDMA MPCP IPACT IPACT with downstream IPACT downstream collision

Power saving design Active to doze Active to sleep Two service level Early wake up Mode transition Our proposal Parameter Sleep time setting

How long can ONU keep in power saving mode? Reference

PON

Passive Optical Network (PON)：▪ A PON is composed of one OLT and multiple ONUs or

ONTs. Optical Line Terminal (OLT)：▪ The OLT resides in the local exchange (central

office; CO) Optical Network Unit (ONU)：▪ The ONU is located at user premises (FTTC,

FTTH,FTTB..) Data Link： SONET、 ATM、 Ethernet Media-access：WDM、 TDM、 CDM

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Access network topologies

[1]

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Passive Optical Network(PON)

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EPON Ethernet Passive Optical Network (EPON)

A PON that carries Ethernet traffic OLT downstream direction (OLT -> ONUs)：▪ TDM▪ Point-to-multipoint▪ Ethernet is broadcasting by nature ▪ ONU extract downstream packets based on MAC

address ONUs upstream direction (ONUs -> OLT)：▪ TDMA▪ Multipoint-to-point▪ Use separate TDM channel

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TDM & TDMA

[7]

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Multipoint control protocol(MPCP) The MPCP is only a message-

exchange protocol Five MAC Control messages：

REGISTER_REQ、 REGISTER、 REGISTER_ACK▪ Used for ONU auto-discovery, registration and

ranging GATE、 REPORT ▪ Used for assigning and requesting bandwidth

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GATE & REPORT format

[7]

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Interleaved Polling with Adaptive CycleTime (IPACT[2])

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IPACT(Cont.)

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IPACT(Cont.)

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IPACT(Cont.)

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IPACT with downstream

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IPACT downstream collision(Cont.)

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IPACT downstream collision(Cont.)

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IPACT downstream collision(Cont.)

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Power saving mode

Active mode (TRx-on) SIEPON (IEEE P1904.1) [2]

Tx sleep mode TRx sleep mode

ITU-T G-series Recommendations – Supplement 45 [3] Doze ( Tx-off, Rx-on) Sleep(TRx-off)

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20[4]

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Active to doze

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Active to sleep

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Two service level

The priority value is using 3-bit field stored in Ethernet frame header defined by IEEE P802.1p High priority for delay sensitive and

bandwidth guarantee traffic▪ Ex: network control , video traffic

Low priority is typically best-effort traffic

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Early wake up

While in power saving mode ONU can do early wake up to transmit high priority data. Sleep to Active aggressive 2ms

(0.125~5.125 ms)[5] Doze to Active (0.125 ms)[5]

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Mode transition

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Our proposal

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Our proposal(Cont.)

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Our proposal(Cont.)

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Parameters 16 ONUs Cycle time 2 ms Guard time = 5 μs MTW = 15000 Bytes

(2ms - 16* Guard time )/16 ONUs/8bit *109

IPACT limited service Optical distribution network(ODN) = 10 Km Packet size = 64~1518 Bytes Timer Y=20ms Tolerate = low priority delay bound ONU, OLT Queue size = 8 Mbytes

1 Gbps/ 16 = 62.5Mbps 62.5Mb/8 = 7.8125 Mbytes ( low priority won’t drop )

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Sleep time setting (Y timer)

[6]

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How long can ONU keep in power saving mode? To keep a watchdog timer in the OLT from

expiring and deregistering the ONU, ONUs should sent MPCP REPORT message to the OLT periodically. (IEEE 802.3ah and IEEE 802.3av)

The maximum duration of the sleep period shall be selected to be less than one second to be avoid automatic deregistration for the ONU under the operation of MPCP timeout mechanism. (IEEE Std 1904.1 )

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Reference [1] G. Kramer, B. Mukherjee, and G. Pesavento, “ Ethernet

PON(Epon): Design and Analysis of an Optical Access Network, ” pp. 1-25, Aug 2000.

[2]G. Kramer, B. Mukherjee, and G. Pesavento, “ IPACT: A Dynamic Protocol for an Ethernet PON (EPON), ”IEEE Commun. Mag., vol. 40, no. 2, pp. 66-73, Feb. 2002.

[3] IEEE Std 1904.1 : “ IEEE Standard for Service Interoperability in Ethernet Passive Optical Networks (SIEPON), ”2013.

[4] ITU-T, “G.Sup 45 : GPON power conservation,”2009. [5] Ahmad R. Dhaini,“Toward Green Next-Generation Passive

Optical Networks,”IEEE Commun. Mag., pp.94-101, Nov. 2011. [6] J. Mandin, “ EPON Powersaving via Sleep Mode,” IEEE

802.3av Meeting, 2008. [7] G. Kramer, “ On Configuring Logical Links in EPON,”

Teknovus, Inc. pp. 1-12.

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Q&A

Thanks for your attention.