Logical object classes and their relationships

This section describes the object classes used in the Optical Transport Managerfor PDH to represent logical entities in optical networks. Several types of logical connection are represented in Optical Transport Manager:

• LowOrder_Circuit---Represents a connection across the entire network which connects two client entry points. A LowOrder_Circuitmay be carried over a number of HighOrder_Trailsand includes end points represented by CTPs(ConnectionTerminationPoints).

• HighOrder_Trail---Represents a circuit that carries a VC3 or higher capacity circuit. HighOrder_Trailsin Optical Transport Managerfor PDH do not include CTPs.

  In the simplest case, a LogicalConnectionis LayeredOvera single HighOrder_Trail. Logical object class relationships in PDHshows the main relationships between CTPs, PTPs, HighOrder_Trails, and LogicalConnectionsfor a simple linear connection.

  Figure 1. Logical object class relationships in PDH

  

  The end points of logical connections are represented by CTPs, which are LayeredOver PTPobjects. Each CTPobject contains the time slot information for the connection that uses it. Many CTPobjects can be LayeredOvereach PTPwhen many low-speed circuits are provisioned on the same higher speed port.

  A LowOrder_Circuit that is LayeredOver other entities as It passes through the network.shows how a circuit passing through the network is modeled.

  Figure 2. A LowOrder_Circuit that is LayeredOver other entities as It passes through the network.

  

  A circuit passing through different vendor equipment (shown as green and blue device symbols) and passing through various protection schemes is modeled by a set of objects that represent physical and logical connections. The LayeredOver relationship is used to define the dependencies between the objects. In A LowOrder_Circuit that is LayeredOver other entities as It passes through the network., when an object is shown vertically above another object, a LayeredOverrelationship is implied.