1 / 31

An Overview of PON Technologies

An Overview of PON Technologies. Pu -Chen Mao 3/21/2011. Outline. Background G-PON EPON NG-PON Future Studies References. Background (1/3). Access technologies Wireless 802.11, 802.16, etc. Low cost deployment

foxm
Download Presentation

An Overview of PON Technologies

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. An Overview of PON Technologies Pu-Chen Mao 3/21/2011

  2. Outline • Background • G-PON • EPON • NG-PON • Future Studies • References

  3. Background (1/3) • Access technologies • Wireless • 802.11, 802.16, etc. • Low cost deployment • Insufficient capacity for high bandwidth (revenue) applications such as IPTV • Copper • DSL • Point-to-point architecture allows unshared bandwidth • Limited distance due to noise • Cost of deployment only slightly less than an all-fiber approach

  4. Background (2/3) • Fiber • Low noise • Long reach • Topology • Tree • More cost effective • Point-to-point • Dedicated fiber plant from CO to subscriber • Ring • Fault tolerant

  5. Background (3/3) • Shared fiber architectures • Active Ethernet • Signals split by electronic equipment • PON • Signals replicated passively by splitter • Higher reliability due to no electronic equipment in outside plant • Signal format transparency • Can be more flexibly upgraded • Requires no electric power source

  6. G-PON • Specified by ITU-T G.984 series • Began in FSAN consortium in 2001

  7. G-PON Layers

  8. G-PON Transmission Convergence (GTC) Layer • Performs adaptation to the physical-medium-dependent (PMD) layer • Adaption methods • ATM • G-PON encapsulation method (GEM) • Preferred method • Ethernet adaptation • TDM adaptation • MAC function • Coordinates interleaving upstream traffic from individual ONUs

  9. GTC Layer • Control functions • Defines protocols & procedures for registering & performance monitoring of ONUs • Configuration of transport features • FEC • Encryption • Bandwidth allocation

  10. GTC Layer • GTC framing sub-layer • Downstream frame format • 125 us • 8 KHz signal for ONU reference clock • Physical Control Block (PCBd) • Framing, PHY operations, PLOAM fields • Message-based protocol for PMD & GTC mgmt. • Bandwidth map field for upstream transmission allocation • Payload follows PCBd

  11. GTC Layer • GTC framing sub-layer • Upstream frame format • Same as downstream 125 us • Physical layer overhead (PLOu) field • Preamble & delimiter configurable by OLT • Dynamic bandwidth report (DBRu) field for DBA traffic queuing reports from ONUs • PLOAM identical to downstream frame • DBRu & PLOAM are optional, requested by OLT

  12. GTC Layer • GTC TC adaption sub-layer • GEM • Protocol independent connection-oriented encapsulation for variable-sized packets • Virtual connection unit: GEM port • 5 byte header • Port ID & frame size • Frames may be fragmented • G.984 specifies transport of Ethernet & TDM over GEM

  13. GTC Layer • T-cont • Each T-cont aggregates one type of traffic out of 5 classes • Composed of multiple virtual port connections

  14. Upstream Bandwidth Allocation • Static method • Dynamic Method (DBA) • Status reporting DBA • ONU reports via DBRu field • Non-status reporting DBA • T-cont utilization monitored by OLT

  15. GTC Control Plane • Operated via PLOAM message protocol and embedded OAM • Management functions • PMD layer management • Upstream config, PHY monitoring, generate stats • GTC layer management • Framing, requesting PLOAM / DBRu, etc. • ONU activation • Activate ONU, ranging protocol, optical power tuning • Encryption management • AES, key exchange procedure

  16. G-PON Management • G.984.4 specifies the ONT management and control interface (OMCI) • OMCI • ONU management information base • ONT mgmt. control channel protocol (OMCC) • Conveys MIB info between ONU & OLT • Models equipment configuration, port types, and service types • QoS

  17. EPON • Ethernet sub-layers

  18. EPON • 1 Gb/s bidirectional links • 1490 nm downstream • 1310 nm upstream • 1550 nm reserved for extensions • 802.3ah EPON • Minimum 1:16 split ratio • Up to 1:64 commercially available • 802.3 similarities • Standard inter frame gap (IPG) • Uses same MAC • Multi-Point Control Protocol (MPCP) for P2MP connectivity • Uses standard Ethernet packets in MAC sub-layer • Modified preamble

  19. EPON Downstream

  20. EPON Upstream

  21. EPON ONU Registration • MPCP handshake • OLT broadcasts GATE message • Unregistered ONUs respond with REPORT and REGISTER_REQ • OLT approves and replies with REGISTER • ONU responds with REGISTER_ACK

  22. EPON Operation • OLT controls ONU transmission windows with GATE messages • ONU responds queue status with REPORT • OLT calculates transmission window length using DBA • Synchronized to PON clock with 16 ns resolution counter in MPCP messages • OLT and ONU exchange timestamps to measure RTT for upstream scheduling

  23. EPON Frame • Downstream preamble • Logical link ID field specifies the destination ONU • ONU filters frames by LLID • ONU receives unique LLID assigned by OLT • Special value of LLID reserved for broadcast • Upstream preamble • LLID marks the source ONU • Ensure preamble field integrity by CRC • One ONU may have multiple LLIDs (virtual ONU) • FEC • Based on RS(255,239) • Frames encoded separately, parity bytes appended to end • Encryption • AES-based

  24. EPON Management • Link layer management • OLT remotely manages attached ONUs • Remote link monitoring • OAM • Established after discovery process • Maintained by periodic messages • Remote failures conveyed in flags of OAM msgs. • OAM using SNMP

  25. NG-PON • Next-generation PON technologies to extend current bandwidth to 10 Gb/s • XG-PON by ITU-T • 10GE-PON by IEEE 802.3av

  26. NG-PON Direction

  27. 10 Gb/s PON

  28. 10 Gb/sPONs • Similarities of XG-PON & 10GE-PON • L-band downstream 1575 – 1580 nm • O-minus band upstream 1260 – 1280 • Mandatory FEC • RS(255, 223) • Video overlay 1550 – 1560 nm

  29. 10 Gb/sPONs • Uniqueness • 10GE-PON • Conflict in EPON 1260 – 1360 nm and 1260 – 1280 nm band used • Share overlapping spectrum using TDMA • XG-PON • 32-bit word aligned framing • XGEM extension • PLOAM, DBRu, bandwidth allocation, ranging functions as clients to XGEM system, with XGEM becoming the main protocol

  30. Future Studies • System architecture, specifications of XG-PON and 10GE-PON • Long-reach PON • DBA comparison for EPON, GPON, and next-generation PON

  31. References [1] Effenberger, F., et al., “An introduction to PON technologies,” IEEE Communications Magazine, Vol. 45, Issue: 3, 2007 [2] Effenberger, F., et al., “Standardization trends and prospective views on the next generation of broadband optical access systems,” IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 28, NO. 6, AUGUST 2010 [3] Paul E. Green Jr., “Fiber to The Home: The New Empowerment”, Wiley, 2006

More Related