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EPON Introduction

EPON Introduction. Speaker : 尹培華 Pei- Hwa Yin 指導 教授：吳和庭老師. Outline. Introduction MPCP (Multi Point Control Protocol ) DBA introduction -IPACT ( Interleaved Polling with Adaptive Cycle Time ) -Priority Queuing Future work Reference.

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EPON Introduction

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  1. EPON Introduction Speaker :尹培華 Pei-Hwa Yin 指導教授：吳和庭老師

  2. Outline • Introduction • MPCP (Multi Point Control Protocol ) • DBA introduction -IPACT (Interleaved Polling with Adaptive Cycle Time ) -Priority Queuing • Future work • Reference

  3. Introduction Develop motivation : backbone bandwidth has experienced substantial growth , but little has changed in the access Network PON is one of solution to this problem due to -low cost -high bandwidth -easy to maintain

  4. Introduction PON : passive optical network - no active elements in the transmission path from source to destination Three basic components : a )OLT (optical line terminal) : - near service provider (control and modify bandwidth) - connect to the backbone network( ex : IP ) b )ONU (optical network unit) : - near end-users c )1:N passive star coupler(splitter or combiner) : - splitter(use in downstream direction) - combiner(use in upstream direction)

  5. Introduction Three common topology type a ) tree (use most) b ) bus c ) ring

  6. Introduction EPON : all data are encapsulated in Ethernet frames for transmission Feature : - long distance : 20 km - more cost effective - higher bandwidth : up to 10Gigabit/second Ethernet frame format

  7. Introduction Upstream direction : ONU->OLT : ONUs share the channel capacity /use TDMA mechanism that control by OLT Downstream direction : OLT->ONU : broadcasting

  8. MPCP(Multi Point Control protocol ) • a control mechanism between a Master and Slaves units connected to a Point-to-Multi-Point (P2MP) segment to allow efficient transmission of data - EPON use this protocol to transfer control message between OLT and ONU - It is a layer 2 protocol - Two mode a)normal mode – Bandwidth assignment / request b) Auto Discovery mode – Control Auto Discovery process

  9. MPCP(Multi Point Control protocol ) • Control message are as follows (defined by opcode field): -GATE -REPORT -REGISTER_REQ -REGISTER -REGISTER_ACK

  10. MPCP(Multi Point Control protocol ) Gate message format： Ps : flag=0/regular flag=1/discover

  11. MPCP(Multi Point Control protocol ) Gate message operation

  12. MPCP(Multi Point Control protocol ) Report messageformat：

  13. MPCP(Multi Point Control protocol ) Report message operation

  14. MPCP(Multi Point Control protocol ) Round Trip Time Measurement- Raging

  15. MPCP(Multi Point Control protocol ) Normal mode

  16. MPCP(Multi Point Control protocol ) Auto-discover mode Which are used to discover and register a newly connected ONU

  17. DBA framework DBA framework overview I

  18. DBA framework DBA framework overview II

  19. Inter-ONU Scheduling-IPACT Step 1 OLT throw Grant/request mechanism has already know the information that bandwidth allocation need and the information are store in a polling table , then OLT will send a message to notify the first ONU the time that can start to transmit data(include data size) Step 2 when ONU get message , it will start to transmit data in the end ,it will send another message to OLT ,to notify how many data that need to transmit next time Step 3 in a proper time OLT will send a grant message to the next ONU repeat 1~3 until end

  20. Inter-ONU Scheduling-IPACT EX:

  21. Inter-ONU Scheduling-IPACT If an ONU emptied its buffer completely, it will report 0 bytes back to the OLT. Correspondingly, in the next cycle the ONU will be granted 0 bytes, i.e., it will be allowed to send a new request, but no data. At the end of its transmission window, ONU will generate its own control message (Request) and send it Back to the OLT

  22. Inter-ONU Scheduling-IPACT Transmission window size -to notify how many data that OLT can send to a ONU Maximum transmission window : -to avoid ONUs with high traffic volumes monopolize the bandwidth Type -FIX -Limited -Gated -Constant Credited -Linear credit -Elastic

  23. Inter-ONU Scheduling-IPACT Max polling cycle time : If all ONU want to transmit data If only one ONU wants to transmit data

  24. Inter-ONU Scheduling-IPACT Fix : Limited : Gated : Constant credit

  25. Inter-ONU Scheduling-IPACT Linear Credit : Elastic :

  26. Intra-ONU scheduling- priority queuing Concept and feature : -Packets are classified by the system and then put in different priority queues - With in each of the priority queues , packet are scheduled as FIFO queue - Packet can scheduled if all higher priority queues are emptied limitation : Low priority queue may suffer starvation Benefits : Can provide simple QoS

  27. Intra-ONU scheduling- priority queuing

  28. Future work -Long reach PON -QoSbase of Dynamic Bandwidth Management in Integrated EPON and 802.16 Access Networks

  29. References [1] Glen Kramer , Davis BiswanathMukherjee, Gerry Pesavento ,Interleaved Polling with Adaptive Cycle Time (IPACT) A Dynamic Bandwidth Distribution Scheme in an. Optical Access Network,PhotonicNetwork Communications ,4 : 1 ,89-107, 2002 [2]N. Ghani, A. Shami, C. Assi, M. Y. A. Raja, Intra-ONU Bandwidth Scheduling in Ethernet Passive Optical Networks,IEEECOMMUNICATIONS LETTERS, VOL. 8, NO. 11, NOVEMBER 2004 [3] IEEE 802.3ah 2004 [4] RFC4837 – Managed Objects of Ethernet Passive Optical Networks ,July 2007

  30. Q&A

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