Circuits

Utilities and telecom organizations manage large networks using smaller logical segments. For example, gas and water utilities use pressure and isolation zones, while electric utilities use feeders and sections modeled using subnetworks. In the telecom industry, circuits are employed.

In the context of the utility network, the term circuit is used to define a collection of components that represent a dedicated path between specified start and stop locations (for example, ports) in a telecom domain network. A circuit is composed of disconnected collections of connected elements, which are called sections in a sectioned circuit. Sections represent a logical collection of elements which can be identified using a trace operation and are defined by one starting point and one stopping point. A circuit can be composed of one or more sections that are partially ordered (arranged in parallel or sequentially), and can also be divided into subcircuits to define another circuit and share capacity or bandwidth. A circuit may also be created without sections to simplify storage or support FTTH circuits and is known as a nonsectioned circuit.

Circuits are created using the Create Circuit pane or the Import Circuit Definitions tool. Circuits are uniquely named by the user and may contain additional user-defined attributes to track information such as circuit bandwidth, ownership, and so on. Devices, junctions, and junction objects are assigned the Circuit Location network category to serve as the start and stop locations for a circuit in the network. A line or edge object can serve as a start or stop location in a circuit when it does not have connectivity on both the From and To sides. In this case, the Circuit Location network category is not required.

Both sectioned and nonsectioned circuits can be modeled as physical circuits, using the physical network infrastructure, or defined logically using the network infrastructure as a virtual circuit. Virtual circuits are commonly defined between start and stop locations where the underlying physical network is unknown.

Circuit management

Circuits are marked as dirty by the following operations:

When the network topology is enabled.
When a circuit is created.
When changes are made to the circuit definition using the Modify Circuit pane.
When edits made to the features and objects which participate in the circuit are validated.
When edits are made to user-defined attribute fields configured to mark circuits dirty.

To ensure correctness, a dirty circuit must be verified. See Verify circuits to learn more about the checks performed when a circuit is verified.

Note:

The Import circuits as clean parameter on the Set Circuit Properties tool allows you to optionally import circuits as clean when using the Import Circuit Definitions tool.

Information about a circuit is stored in the circuit management tables. When the first telecom domain network is created, three additional tables are created to support circuit management in the network.

The Circuit table stores information about the circuits and the sections (when present) that define each.
The CircuitSection table stores information about the sections which define the circuits. A circuit can have multiple records in the table where each row represents a section (starting point, stopping point, or subcircuit) used in the section.
The Subcircuit table stores information about circuit subdivisions (subcircuits) which share the capacity or bandwidth of a circuit.

Information about the features and their connectivity that comprise a circuit in a telecom domain network can be exported to .json files using the Export Circuits tool. This exported data can be used for archiving or in other tools using ModelBuilder, custom tools, or through integration with external third-party systems.

The Set export acknowledged parameter can be used to specify whether external systems will be notified about the circuit. If a circuit has been logically deleted from the network (Status = Deleted), the Export Circuits tool allows you to physically delete the row from the Circuit table when the Set export acknowledged parameter is checked.

Tracing a circuit

Features participating in a circuit are not stored in the circuit definition, except those associated with the start and stop locations. Trace operations are used instead to identify circuit participation. To account for the deep containment hierarchies common in telecom organizations, two trace types are available for circuit analysis: path trace and circuit trace.

Path trace

A path is a sequence of junctions and edges with a defined starting point and an optional stopping point. When stopping points are not explicitly provided, stop locations for a path trace are defined when barriers are encountered, when the maximum number of hops (Max Hops) defined for the trace has been reached, and when the trace encounters junctions at the endpoint of the path with a valence of 1. While a circuit only contains a single path between the start and stop locations which define it, the path trace helps to identify valid paths that exist between one or more start and stop locations when defining a section and creating a circuit. Grouping is supported, and the Num Paths and Max Hops parameters are provided to help constrain the valid paths that are returned. For cases in which circuits are modeled without all connectivity explicitly specified, the Infer Connectivity parameter can be used on traversal to find a path using a feature's containment hierarchy.

Circuit trace

A circuit trace uses the Circuit Name or a starting point to return the features which define a circuit. This can be used to trace and return information for virtual circuits and circuit sections which are not represented in the network topology. The circuit trace can return a selection, aggregated geometry, or circuits result. When the Circuits result type is used, the circuit definition is returned along with information about the features which comprise the path in an output .json file.

Circuit properties

Circuits are assigned an initial property set when the telecom domain network they reside in is created; however, you can set or modify the properties for circuits using the Set Circuit Properties tool.

The telecom domain network controls the various properties for all circuits it contains. These properties are referenced when creating, modifying, and tracing a circuit.

The following table describes the components of a telecom domain network's circuit properties:


Component	Description
Share circuit locations	Specifies whether the start and stop locations used to define a circuit can be shared between circuits. Checked—A start or stop location can be used to define one or more circuits. Unchecked—A start or stop location can only be used to define a single circuit. This is the default. Note: This applies to all start and stop locations which define a circuit. A junction or junction object must be assigned the Circuit Location network category to serve as the start or stop location for a circuit or circuit section; however, a line or edge object does not require the Circuit Location network category and can serve as the start or stop location when it does not have connectivity on both the From and To sides.
Import circuits as clean	Specifies whether circuit definitions imported using the Import Circuit Definitions tool are imported to the Circuit table as Clean or Dirty. Checked—The `Status` attribute for imported circuits is Clean and the `Last verified` field is null. When the network topology is disabled, the `Status` field is not updated. Unchecked—The `Status` attribute for imported circuits is Dirty. When the network topology is disabled, the `Status` field for all circuits is updated to Dirty. This is the default.
Circuit Trace Configuration	The circuit trace configuration is optional and can be set during the configuration stage of a utility network using the Set Circuit Properties tool. This is used when creating, modifying, verifying, and tracing circuits in the network. The configuration options are as follows: Max Hops—Specifies the maximum number of hops between edges that will be allowed in the path, excluding the starting point. All edges and junction-junction connectivity associations are evaluated as having a fixed unit length of 1 on traversal. The default is 100. Include containers—Specifies whether containers of traversed features will be included. Include content—Specifies whether content of traversed features will be included. Include structures—Specifies whether structures with attachments to traversed features will be included. Include barrier features—Specifies whether barriers will be included. Validate locatability—Specifies whether an error will be returned if unlocatable junction or edge objects are encountered. Summaries—This parameter is not currently implemented and is reserved for future work. Condition Barriers—Defines a feature or object that will stop a trace operation based on network attributes and categories. Function Barriers—Defines a feature or object that will stop a trace operation based on a function. Apply Traversability To—Defines the traversability scope to enforce. Apply traversability to only junctions, only edges, or both junctions and edges. Propagators—Specifies the network attributes to propagate as well as how that propagation will occur during a trace.
User Attributes Marking Circuits Dirty	User-defined attribute fields on circuit management tables can optionally be configured to mark a circuit as dirty when modified. Use the User Attributes parameter to specify the circuit management table and attribute name for each field. The configuration options are as follows: Circuit Table—Specify the circuit management table containing the user-defined attributes. Attribute Name—Select the fields from the specified table that should mark a circuit as dirty when modified.

Learn more about how to set or modify the circuit properties