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Passive Optical Network Testing and Consulting

Passive Optical Networks (PONs) are an emerging broadband, multi-services, access technology allowing the benefits of fiber optic transmission to be pushed closer to the customer, including directly to the customer location. Installed first costs are reduced by allowing optical transceiver at the network end of the access system to be shared with many customers and minimizing the number of trunk/feeder fibers (i.e., fibers leaving the network's OLT function). Operations cost are reduced by the passive nature of the optical distribution network.

High-level PON Example
High-level PON Example

Four general categories of PON testing include:

Passive Component Testing

Passive component testing focuses on the optical performance of the connectors, splitters and network interface devices that comprise the passive optical distribution network.

Telcordia Technologies provides a wide array of consulting, testing, and analysis capabilities supporting Optical Infrastructure components. Service provider RFPs typically specify conformance testing to Telcordia documents including, but not limited to:

Telcordia Technologies provides complete testing and analysis programs to independently verify product conformance to the above documents, as well as many other Telcordia optical infrastructure documents and numerous IEC, EIA/TIA and other standards bodies developed documents covering fiber optic cable, connectors and related devices.

Telcordia's expertise in fiber optic technologies also encompasses fiber optic infrastructure performance / failure analysis including optical fiber / cable / connector fractography, analysis of contaminants on fiber-based components, and measurement of chromatic / polarization mode dispersion in fiber optic communications systems / networks. In addition, Telcordia services offered to service providers and other owners of fiber optic networks have included the following:

  • Custom specifications development and testing requirements for optical fiber and connector functionality, performance, reliability, and interoperability.
  • Supporting decision-makers in product procurement, evaluation, and supply chain management.
  • Recommending and preparing upgrade plans, test specifications, methods and procedures, and training.
  • Detailed analyses, field measurements, and upgrade feasibility assessments of candidate products and routes under consideration.
  • Field-testing and characterization of existing fiber plant infrastructure.
  • Custom methods to install and maintain the fiber optic network for minimum cost and maximum performance.

Please contact Rudi Schubert (+1 732-699-3460) or Osman Gebizlioglu (+1 732-699-3378) for additional information on optical infrastructure component testing and consulting services.

System Testing

System testing focuses on testing the Optical Line Termination (OLT), Optical Distribution Network (ODN), and Optical Network Unit/Termination (ONU/ONT) as a complete system. A number of different ODN configurations are applied to stress the operation of the PON system, while performance is examined at the customer service and network interfaces.

System testing is a current test capability available at Telcordia. The monitoring points associated with PON system testing are illustrated in the figure below.

PON System Test Points
PON System Test Points

For telephony service, performance would be assessed between reference points 3B/C and 3A. Video service performance would be examined between 1B and 1A. Internet access service would be examined between reference points 2B and 2A. Testing would be performed under various PON traffic loads and with various PON ODN configurations.

Specific system performance areas that would be examined include:

  • System Data Transmission Performance Measurements (e.g., throughput, latency, lost frames under various optical layer impairment and topological conditions)
  • ONU Discovery and Ranging Operation
  • Bandwidth Sharing Operation (possibly with various PON dynamic bandwidth allocation (dba) schemes - if supported)
  • Quality of Service Support (traffic conditioning operation, operation with various class of service and traffic contracts, DBA/QOS interaction, etc.)
  • PON Protection Scheme Operation (if provided)
  • Service Operation (e.g., DS1 CES, LAN Emulation, voice over AAL1/AAL2, voice quality, video quality, etc.)
  • Conformance at External Interfaces (customer and network)
  • PON OAM&P (configuration, fault, and security management operation)

Interoperability Testing

Interoperability testing builds upon system testing by inserting a PON monitoring device between the OLT and ONU/ONT, allowing optical, control, and management plane information to be analyzed. Looking inside the PON is a critical tool to helping to isolate the cause of interoperability problems between the OLT and ONU/ONT devices.

This is a future Telcordia testing service offer. It builds on the PON system testing by adding the ability to monitor and decode PON optical, control, and management plane information.

Conformance Testing

Conformance testing examines the optical, control, and management plane conformance to the criteria specific in an appropriate standards document (e.g., ITU-T FSAN/G.983/G.984 or IEEE 802.3ah). In addition, error handling test cases are run to determine the OLT or ONU's response to unexpected protocol behaviors. Conformance testing requires the use of an OLT and ONU/ONT emulator/analyzer to serve as part of the conformance testbed.

This is a future Telcordia testing service offer. Conformance testing provides a more detailed look at a supplier's PON implementation relative to a reference specification. Protocol exception handling behaviors are examined as part of unit conformance testing.

PON System Consulting

Telcordia provides consulting services related to PON System interfaces, optical component reliability and performance, and PON deployment issues. Please contact Scott Yeomans (+1 732-699-3443) for additional information on PON related testing and consulting services.