Two Worlds Collide, Rival Junctions

June 23, 2014 — Brian Higgins

The Esri Geometric Network has a few simple “rules”.  One of the most basic is that two point features (i.e., junctions) of the same network cannot occupy the same coordinates/position.  Schneider Electric’s standard Fiber Manager™ model typically has six (6) point feature classes in the network as follows:

  • Patch location
  • Splice Location
  • Slack Loop
  • Splitter
  • Transition Point (i.e., Riser)
  • Device Point

So….what happens when two features do occupy the same location?  In a previous blog post, I discussed incorporating a length field to the Splice.  In essence, this modification combines the “world” of the Slack Loop or Riser with the “world” of the Splice.  And in last month’s blog post, I discussed how to model an inside plant cable within a Patch Location.  Again, historically to Fiber Manager™, two different “worlds”.

The vast majority of the Fiber Manager™ implementations that I have conducted have the Splice and the Splitter as separate feature classes: a splice being a 1:1 relationship (one light going in and one light going out) and a splitter being a 1:M relationship (one light going in and is broken up into multiple strands and/or possible paths).

So….What happens when a Splitter is contained within a splice case?  If this situation occurs for that type of deployment, two points must be digitized with a Fiber Optic Cable(s) (Network Edge) drawn in between (Figure 1).

Splice and Splitter As Seperate Feature Classes

A potentially better solution is to make a splitter a related object of splice case and make the Splitter Input Port and Output Ports related child objects of the Splitter.  This option offers the advantage of having to digitize only one point.  If you are an existing Fiber Manager™ user and if you have the presence of a Splitter Object (probably named F_Splitter), all an administrator has to do is add a relationship between the splice and the splitter object (note that it is assumed that if the F_Splitter object is present, the F_SplitterInputPort and F_SplitterOutputPort are present).  Below are the parameters for the relationship:

  • Type:  Simple
  • Cardinality:  1:M
  • Original Feature Class/Primary Key:  SplicePoint/GlobalID
  • Destination Table/Foreign Key:  F_Splitter/FiberParent
  • ArcFM™ On Relationship Created AU:  ArcFM™ Update Fiber Parent Field

Lastly, given this first scenario, assign the SplicePoint Feature Class field FiberChildClassModelName the Default Value of SPLITTER.

As a second scenario, if the F_Splitter, F_SplitterInputPort, and/or F_SplitterOutputPort objects are not present in your model, they must be generated and modeled as follows (at a minimum):

F_Splitter Object Table

F_SplitterInputPort Object Table

F_SplitterOutputPort Object Table

Following the addition of some or all of the above three tables, the administrator must verify/add the following Esri relationships between the parent (listed first) and child (listed second): 

  • SplicePoint (or name of Feature Class) / F_Splitter (Relationship discussed earlier)
  • F_Splitter / F_SplitterInputPort
  • F_Splitter / F_SplitterOutputPort
  • F_SplitterInputPort / F_SplitterOutputPort

With the exception of the last relationship (F_SplitterInputPort / F_SplitterOutputPort), all relationships are Composite and 1:M.  The Primary Key is the GlobalID field, and the Foreign Key is the FiberParent field.  The F_SplitterInputPort / F_SplitterOutputPort relationship is Simple and also 1:M.  This last relationship’s Primary Key is the GlobalID field and the Foreign Key is the ImpliedConnectionSourceGUID field.

With the exception of the last relationship, assign the ArcFM™ AutoUpdater (On Relationship Create) to ArcFM™ Update Fiber Manager™ Field.  There is no AutoUpdater assignment to the F_SplitterInputPort / F_SplitterOutputPort relationship.

To conclude, once the discussed configuration has been implemented and tested, users will be able to utilize the ArcFM™ Location Editor to “drag” splitters to an existing splice case.  It should also stated that these instructions could also easily be applied to a Splitter contained within a Patch Location Rack. 

By the way, the title should be credited to the classical 80’s rock group Survivor in the song “Burning Heart”.  The song was featured in the movie Rocky IV.

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Brian Higgins

Solution Architect

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