Passive Optical Network

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Passive Optical Network -Protocols-
Present Rony Levin Email levinbr_at_ee.bgu.ac.il Co
urse Optical Communications Networks
Number 361-2-5571 Lecturer Prof. Dan Sadot
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Agenda

• Historical Overview
• Terms Definition
• PON Overview
• PON Protocols Overview
• PON Protocols Comparison
• Summary

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Communication Problem
Converter

• If good network user connect to another user
  in the same network he can enjoy from high
  quality service, but if he will try to connect to
  user belong to bad network, the received
  service will be terrible.
• Of course, he will accuse good network
  vendoroperator

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Communication Problem

• In order to avoid such kind of problems
  vendorsoperators have been compelled to
  cooperate, although they were competitors.
• Communications protocol were developed to supply
  data streaming, using some kind of common used
  rules.
• Today, when optical communication industry is
  developed, nobody wants to repeat previous
  mistakes

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Who Is Who

• FSAN Full Service Access Networks (from 1995)
• ITU-T International Telecommunication Union
  Telecommunication Standardization Sector
• IEEE Institute of Electrical and Electronics
  Engineers
• Infonetics Research (www.infonetics.com) is an
  international market research and consulting
  firm specializing in telecom and data networking

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How Does It Work
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FTTx Fiber-To-The-x

• FTTH - Home
• FTTC - Curb
• FTTN - Node or Neighborhood
• FTTP - Premise
• FTTB - Building or Business
• FTTU - User
• FTTZ - Zone
• FTTO - Office
• FTTD - Desk

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Acronyms

• OAN Optical Access Network
• ODN Optical Distribution Network
• ONU Optical Network Unit
• OLT Optical Line Termination
• ONT Optical Network Terminal
• CO Central Office
• QoS Quality of Service
• SLA Service Level Agreement
• AGC Automatic Gain Control

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Vicious Cycle
Don't want to pay more for bandwidth or QoS
because there are no applications or services
that require them
Don't want to upgrade the networks because users
are not willing to pay for QoS or higher bandwidth
Don't want to develop new applications
or services because there is no
network infrastructure available to support them
User
Network Operator
Content Provider
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Virtuous Cycle
Demand more bandwidth and QoS to receive new
applications and services
New infrastructure is deployed to support new
applications
User
Emergence of and competition among new
applications
Network Operator
Content Provider
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Last/First Mile Problem
Metro-Area Network
Local Area and Home Network
Access Network Last/First mile
10 Gb/s Tb/s
1 Gb/s 40 Gb/s
1 Mb/s 1 Gb/s

• Cooper wire technology
• Dial-up 56Kb/s
• DSL/Coax 100Kb/s5Mb/s

Backbone
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PON - Last Mile Problem Solution
PON Passive Optical Network Point-to-multipoint,
consist of one OLT at the CO, OAN(20 km),
passive optical splitter and optical fibers, that
allow to serve one and more ONUs
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First Mile Evolution

• Point-to-point links
• N fibers
• 2N optical transceivers
• Concentration switch in the neighborhood
• 1 fiber
• 2N2 optical transceivers
• Electrical power in the field
• PON a distributed switch
• 1 fiber
• N1 optical transceivers
• No electrical power in field
• Downstream broadcast

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Fiber vs Cooper

• Fiber is less costly to maintain than copper
• based systems (though they are costly to
• install)
• PON transmission is conducted through a
• single strand and thereby conserves fiber
• PON conserves optical interfaces at the OLT
• because a single fiber is used to service as
• many as 32/64/128 end-user locations
• Aggregation and concentration in the OLT

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PON Architecture
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PON Topologies
Tree topology
Ring topology
Bus topology
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PON Standardization

• ITU-T G.983
• APON ATM Passive Optical Network
• BPON Broadband PON, is a standard based on APON
• ITU-T G.984
• GPON Gigabit PON, is an evolution of the BPON
  standard
• IEEE 802.3ah
• EPON or GEPON Ethernet PON, is an IEEE/EFM
  standard for using Ethernet for packet data
• IEEE 802.3av
• 10GEPON 10 Gigabit Ethernet PON, is an IEEE Task
  Force for 10Gbit/s backwards compatible with
  802.3ah EPON

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PON Standardization

• ATM PON (APON)
• First PON standard, primarily business
• Broadband PON (BPON)
• Expanded version of APON, supporting WDM,
  survivability, dynamic upstream, bandwidth
  allocation, higher upstream rates
• Giga PON (GPON)
• Evolution of BPON to higher rates, choice of L2
  support (Ethernet or ATM), enhanced security
• Ethernet PON (EPON)
• IEEE/EFM standard using Ethernet for packet data
• 1.25Gpbs up/downlink, DBA, OAM, etc.

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ATM
ATM has its roots in the telephone
business Connection-oriented protocol with
excellent QOS When a connection is made, it
exists for the entire communication session,
ensuring a reliable channel
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Ethernet
Ethernet has its roots in office data
systems Connectionless-oriented, with excellent
efficiency Packets are transmitted individually,
requiring resources only when they are being
transmitted
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TDM PON

• Each ONU transmits in its own window (time slot)
• All ONUs operate on the same wavelength with
  identical components
• Most of the traffic flows downstream, but not
  peer to peer (user to user)
• Two wavelengths are used 1310 nm (?1) for
  upstream transmission and 1550 nm (?2) for
  downstream transmission

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TDM PON
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EPON DOWNSTREAM TRAFFIC

• In the downstream direction, Ethernet frames
  transmitted by the OLT pass through a 1N passive
  splitter and reach ONUs
• Broadcast by nature
• Packets are broadcast by the OLT and extracted by
  their destination ONU based on the media-access
  control (MAC) address

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EPON DOWNSTREAM TRAFFIC
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EPON UPSTREAM TRAFFIC

• In the upstream direction, data frames from ONUs
  reach only the OLT, and not other ONUs
• Each ONU buffers the upstream LAN traffic and
  sends it to the OLT when its window is open
• Upstream B/W is controlled by the window size per
  ONU

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EPON UPSTREAM TRAFFIC
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WDM PON

• Each ONU has dedicated wavelength

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TDM-PON vs WDM-PON
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PON Market

• North American market GPON
• Asia (Japan and Korea) EPON
• Sales of Ethernet FTTH equipment surged 89 in
  2007 over 2006 . The number of worldwide PON and
  Ethernet FTTH subscribers topped 12.6 million in
  2007 and is forecast to grow to 80.5 million in
  2011

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EPON vs GPON Framing
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Protocol Comparison
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Any Question?
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Thank You for Attention