Next Generation SONET Protection Schemes

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Next Generation SONET Protection Schemes

• Bobby Scharmann
• Shilpa Choudhary
• July 27 2005

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Overview

• Background Information
• SONET Details
• Protection/Restoration Schemes
• OPNET
• DARPANET/NSFNET
• Results
• Summary/Conclusions

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Network

• A network is simply a group of devices connected
  to share resources.
• Centralized vs. Distributed

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Network Topologies

• Mesh Topology
• Star Topolgy
• Ring Topology

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Mesh Topology

• Advantages
• Few Traffic Problems
• Robust to Failures
• Privacy and Security
• Disadvantages
• Cabling is Expensive
• Figure from http//www.webopedia.com/TERM/t/topol
  ogy.html

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Star Topology

• Advantages
• Less Expensive (Cabling)
• Robust to Link Failures
• Disadvantages
• Less Secure
• Central Point of Failure (Hub)
• Figure from http//www.webopedia.com/TERM/t/topol
  ogy.html

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Ring Topology

• Advantages
• Simplicity
• Disadvantages
• Lack of topological node degree
• Figure from http//www.webopedia.com/TERM/t/topol
  ogy.html

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Flow Control

• Flow Control Procedure to ensure the transmitter
  does not overload the receiver
• Stop and Wait
• Sliding Window

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Routing Data Across a Network

• Circuit Switching
• Packet Switching
• ATM/Frame Relay

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Circuit Switching

• Dedicated communications path is created through
  the nodes of a network
• Advantages
• Network Resources are Static (Dedicated)
• Disadvantages
• Network Resources Wasted
• Initial Overhead

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Packet Switching

• Data traverses nodes in the network from the
  source node to the destination node.
• Advantages
• Network resources can be shared
• Simpler and no call setup
• Disadvantages
• Greater delay in getting from source to
  destination
• Overhead for error-checking

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Asynchronous Transfer Mode (ATM)/Frame Relay

• ATM Similar to packet switching without the
  overhead, but data is broken up into fixed length
  packets (called cells) (53 bytes 48 bytes for
  data 5 bytes header)
• Frame Relay Similar to packet switching without
  the overhead, but data is broken up into variable
  length packets called frames

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Multiplexing Techniques

• Time Division Multiplexing (TDM)
• Statistical Time Division Multiplexing (STDM)
• Frequency Division Multiplexing (FDM)

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Time Division Multiplexing (TDM)
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Statistical Time Division Multiplexing

• Essentially a special case of TDM where if one
  input isnt sending data another input can send
  data

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Frequency Division Multiplexing (FDM)
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Overview

• Background Information
• SONET Details
• Protection/Restoration Schemes
• OPNET
• DARPANET/NSFNET
• Results
• Summary/Conclusions

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SONET/SDH

• Synchronous Optical Network /Synchronous Digital
  Hierarchy
• SONET /SDH, a high speed transmission technology
  designed to send traffic over fiber optical cable
  
• Standard for optical telecommunications transport
  of TDM data
• Network Styles
• Expected standard for next two decades

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SONET Specification

• STS-1 Synchronous Transport Signal-1 -
  Electrical rate used within specific hardware
• OC-1 Optical Carrier
• - Optical equivalent for transmission across
• fiber

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The SONET/SDH Digital Hierarchy
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SONET FRAME

• SONET frame is a block of 810 bytes put out every
  125 microsec.
• Described as a rectangle of bytes which consist
  of 90 columns and 9 rows.
• There are 3 basic parts to each frame The
  section overhead, the line overhead and the
  synchronous payload itself.

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Limitation of SONET

• SONET traffic is carried in fixed bandwidth
• groups
• SONET has no built-in capability of
• dynamically shifting bandwidth usage

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DWDM

• Dense wavelength division multiplexing
• A form of frequency division multiplexing.
  Divides bandwidth of an optical fiber into many
  non-overlapping ?s
• Cost Effective
• Scalability

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Next Generation SONET

• New development of SONET/SDH Next generation
  SONET/SDH (NGS)
• Next-generation SONET is the evolution and
  enhancement of existing SONET networks that sets
  a new economic level for network efficiency while
  increasing broadband service potential.

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Enhancements in SONET

• Enhancements include
• Virtual concatenation (VCAT)
• An inverse multiplexing technique
• Link capacity adjustment scheme (LCAS)
• Dynamically add/remove VCG members

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VCAT

• Virtual Concatenation allows number of small
  containers (e.g. STS-1) can be concatenated and
  assembled to form a larger sized container.

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Virtual Concatenation
No Concatenation
VCAT
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Inverse Multiplexing

• A single "pipe" or data stream is split apart
  into multiple T-1 or E-1 data streams and then
  recombined to form the original stream.

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Overview

• Background Information
• SONET Details
• Protection/Restoration Schemes
• OPNET
• DARPANET/NSFNET
• Results
• Summary/Conclusions

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Protection/Restoration Schemes

• Protection (Pre-provisioned) to resolve a
  conflict due to a failure prior to the failure
  occurring
• Restoration (Post-provisioned) to resolve a
  failure only once the failure has occurred
• Types of Protection
• 11 (Full)
• MN (N number of working lines, M number of
  protection lines)
• Tiered (Partial)

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Protection Illustration
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Restoration Illustration
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11 Protection (Full)

• Protection Essentially providing a dedicated
  line as backup in case the primary line fails

Primary
Backup
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MN Protection

• Protection Essentially providing M lines of
  backup for every N primary lines

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Tiered Protection

• Protection Essentially a partial protection
  scheme whereby only a certain ratio (?
  protection factor) of the lines are protected.
  Primarily for NGS VCAT inversed-multiplexed
  networks
• Network protection as opposed to link protection

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Tiered Protection
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Overview

• Background Information
• SONET Details
• Protection/Restoration Schemes
• OPNET
• DARPANET/NSFNET
• Results
• Summary/Conclusions

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OPNET ModelerTM Tool

• Convenient graphical editors
• Easy to use point n click functions
• Complete C/C interface for detailed coding

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Workflow for Modeler

• In this workspace, you can create a network
  model, collect statistics directly from each
  network object or from the network as a whole,
  execute a simulation, and view results.

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Network Model

• The project editor develops the network model,
  which comprised of a subnet and its nodes

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Node Model

• Define the behavior of each network Object
• A single network object is typically made up of
  multiple modules defining its behavior

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Process Model

• The process model allows one to define the
  different protocol states used in the discrete
  event simulation.
• The process model allows one to use C/C to
  program the functionality of the node modules

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Simulation Sequence Editor

• Control the simulations run-time characteristics

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Overview

• Background Information
• SONET Details
• Protection/Restoration Schemes
• OPNET
• DARPANET/NSFNET
• Results
• Conclusions

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NSFNET DARPANET
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Overview

• Background Information
• SONET Details
• Protection/Restoration Schemes
• DARPANET/NSFNET
• OPNET
• Results
• Summary/Conclusions

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Results
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Results
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Results
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Results
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Results
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Overview

• Background Information
• SONET Details
• Protection/Restoration Schemes
• DARPANET/NSFNET
• OPNET
• Results
• Summary/Conclusions

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Summary

• Literature Review
• OPNET Tutorials
• Simulations

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Conclusions

• The less protection offered the greater the
  carried load
• The lower the node degree the greater the
  blocking probability
• The higher the node degree the greater the
  availability

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Acknowledgements

• Dr. Ghani and Dr. He
• National Science Foundation and Electrical
  Engineering Department
• Murali Hari
• Joseph Ayeleso
• Gary and Karthik

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THANK YOU!