QoS

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QoS
Bandwidth Allocation
for
EPON
Midterm Presentation
Project Advisor Nir Naaman Nadav Aharony
Eyal Nave
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Presentation Overview

• Background - 802.3ah EPON
• Project Description
• Project status and advancement plan

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Project Background
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IEEE 802.3ah
IEEE 802.3 Ethernet 802.3ah
Ethernet in the First Mile (EFM) Task Force
Current stage nearing task force draft Expected
Standard Approval 3rd quarter 2003
Scope Ethernet Over Copper (P2P) Ethernet Over
Fiber - (P2P P2MP)
Current initiative defines the fiber access rate
at 1Gbps Future expansions to 10Gbps
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PON Access Network
PON Passive Optical Network
EPON Ethernet over PON
Central Office (CO) OLT Optical Line
Terminal Customer Premise (CP) ONU Optical
Network Unit
Preliminary Approximation for a 1Gb Link 32
64 ONUs
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Downstream Model
Data in true Ethernet frames
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Upstream Model

• TDMA
• No collisions
• No fragmentation

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The Project
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Project Goal
Design and test bandwidth allocation
algorithms for the EPON upstream

• Design and analyze several bandwidth allocation
  algorithms
• Create EPON simulation in OPNET

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Project Stages
Scheduling Algorithms
OPNET Simulation
Project Definition
Proposals and Fine-tuning
Prototype
Basic Scenario (Phase 1)
Analysis
Comparison
Algorithm Simulation
Conclusion
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Test Scenario
Grant Allocation Messages
Downstream Bus
Upstream Bus
TDMA ONU Traffic Status Reports
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OPNET Prototype
Goal Construct a basic OPNET model of EPON

• Main Features
• Add 802.3ah packet formats (new MAC messages)
• TDMA bandwidth allocation scheme
• ONU
• Filter GATE messages and act upon them
• Generate REPORT messages based on queue status
• OLT
• Collect reports from all ONUs
• Ability to generate GATE messages
• Basic statistics gathering

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ONU Data Path
To PON
REPORT Msgs
From PON
MAC Control Msgs
1 Gbps
ONU Traffic
ONU Data
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ONU Scheduler
Future control msgs
Schedule Grant Interrupts
End Transmition Actions
Start Transmition Actions
Generate Status Report
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OLT Data Path
To PON
GATE Msgs
From PON
MAC Control Msgs
1 Gbps
Upstream Data
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OLT Scheduler
Collect and handle reports
Future control msgs
Compose GATE messages based on Grant Table and
send to Network
Insert Algorithm Here!
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New MAC Messages
REPORT
GATE

• GATE
• Start Time
• Length
• Generate Report?

REPORT Status of 8 Priority Queues
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Project Status
Scheduling Algorithms
OPNET Simulation
Project Definition
Proposals and Fine-tuning
Prototype
Semester 1
Basic Scenario (Phase 1)
Semester 2
Analysis
Comparison
Algorithm Simulation
Conclusion
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• The Presentation Ends
• The Work Continues

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From here on the slides are to be hidden
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Why EPON?

• The combination of Ethernet and PON many
  benefits
• Future-Proof Can adapt to all foreseeable
  access applications
• Ethernet is widely spread and implemented
• Will enable a single end-to-end protocol
• Scaleable and even dynamic bandwidth for each
  subscriber
• Single approach for different architectures
• Passive fibers offers lower maintenance and
  expences, and easy line-rate upgrades

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Traffic

• EPON is ultimately intended to converge all of
  the subscribers communication traffic
• Plain old telephony system (POTS)
• Voice and video digital telephony
• Data IP traffic
• Legacy TDM traffic (E1,T1 etc.)
• Television broadcasts/Video on demand
• Any other foreseeable service type

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Scheduling Principles

• Global clock in OLT
• PHY-ID entities enable grant flexibility
• GATE message defines start-stop times for each
  transmission
• Laser power-on/off delay
• ONU\OLT scheduler not defined by standard.

The Standard allows great freedom in
implementation
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MPCP
MPCP Multi Point Control Protocol

• Adds new MAC Control messages.
• Functions performed
• Controlled network boot process
• (REGISTER_REQ,REGISTER, REGISTER_ACK)
• Bandwidth assignment to end-stations
• (GATE)
• Bandwidth polling from end-stations
• (REPORT)

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The Problem
The project concentrates on the bandwidth
allocation problem of the upstream link from the
OLTs point of view in a scenario with multiple
ONUs, a single subscriber per ONU, each employing
multiple traffic types (CBR and BE at the least),
each with its own QoS parameters .
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Our Mission

• Propose and analyze several bandwidth allocation
  algorithms.
• Construct an EPON simulation in OPNET, matching
  802.3ah, and enabling insertion of different
  scheduling algorithms.
• Build an appropriate OPNET scenario.
• Simulate proposed algorithms.