OSS Sandpit – GPON Network Inventory Prototype

This article provides a tutorial for building GPON (Gigabit Passive Optical Network) components into the inventory module of our Personal OSS Sandpit Project. It’s also a model for FTTH / FTTP (Fibre to the Home, Fibre to the Premises) as well.

This prototype build includes components such as:

  • Passive Optical Network (cables, patch panels, splices, splitters, containment, multiports, other splice joints)
  • Active GPON equipment (OLT, ONT)

This GPON prototype can be summarised as follows (this invented network section has been visualised using Google Earth). Note that you should start from the Central Office / OLT site and trace outwards towards the ONT:

This represents the physical representation of a typical GPON model such as the following:

Device Instances

The diagram below shows the new devices we’ve built to support this GPON network model:

This includes:

  • An OLT at the Central Office, (Nokia ISAM FD 7302)with:
    • 18 Available card slots
      • Containing GPON cards (Nokia FGLT-8 cards)
        • 8 GPON ports
  • An FDH (Fibre Distribution Hub) that contains patch arrays and splitters
  • Manholes / Handholes containing:
    • Splice Joints (eg AJL, LJL types)
    • Fibre Loops
    • Multiports (MPT)
  • Cables (mains, distribution and lead-ins)
  • ONTs (Optical Network Terminal devices) on the customer premises

Physical Connections

There is quite a lot of patching and port mirroring required to create the physical connectivity between the customer sites and central office.

This includes a small section of local fibre network (LFN) drawn in Google Earth:

You’ll notice the 4 x Lead-in cables emanating from handhole HH-D-005. The green squares indicate handholes. The blue diamond represent multiports and the blue arrowheads represent AJL / LJL splice joints.

These are shown as follows in the Kuwaiba OSP view:

The diagram below shows the conceptual view of the GPON network in the upper section, with corresponding physical path trace shown in the lower section (Points given for anyone who can spot the error in the text I’ve overlaid on the trace).

Click on the image above to show the more detailed trace from the OLT through the splitter at the FDH to the four homes. Note that the next version of Kuwaiba is expected to show a more fanned-out visual presentation of the trace data.

The same data can be shown in the physical tree view below. You’ll notice that four separate branches emanate from the Splitter inside the FDH, indicating a 1:4 split (although only 3 branches are visible below).

You’ll notice that in this instance, we have to perform a TraceDown (ie from OLT to premises) using the trace Physical Tree functionality. TraceUp (ie from premises to OLT) provides slightly spurious data.

We’ve excluded details about creating fibre joints (eg AJLs, LJLs, etc) and splicing to simplify the scenario, but more details and screen-caps of cable management can be found in this earlier inventory article)

Service Modelling

The diagram below shows that we’ve modelled two service types for each customer here:

  • One for GPON line rental
  • The other is for a retail service – connection to the Internet via Carrier / ISP

Note that the right-hand pane shows customer details for this service.

The diagram below shows more Service Impact details (ie the resources that the GPON service is utilising):

Note that it displays these associations in alphabetical order, not in a traceUp or traceDown sequence.

Summary

I hope you enjoyed this introduction into how we’ve modelled a sample GPON network into the Inventory module of our Personal OSS Sandpit Project. Click on the link to step back to the parent page and see what other modules and/or use-cases are available for review.

If you think there are better ways of modelling this network, if I’ve missed some of the nuances or practicalities, I’d love to hear your feedback. Leave us a note in the contact form below.

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