Logical connection classes and their relationships

This section describes the object classes used in the Optical Transport Manager to represent logical entities in optical networks.

End points of logical connections are represented by CTPs (ConnectionTerminationPoints). Several types of logical connection are represented in Optical Transport Manager:

• LogicalConnection---Represents a connection across part of a subnetwork, such as a protection group.

• SubnetworkConnection---Represents a connection that crosses a subnetwork.

• MeshSubnetworkConnection---Represents a subnetwork connection across a group of devices that implement mesh connectivity and rerouting within the mesh when problems are detected. For instance, Ciena devices can be configured in this manner.

• HighOrder_Trail---Represents a trail, with a VC-4 or higher capacity, that carries low-order and high-order circuits.

• Circuit---Represents a connection across the entire network which connects two client entry points. A circuit may be carried over a number of SubnetworkConnections and/or MeshSubnetworkConnections.

  • HighOrder_Circuit---Represents a circuit that carries a VC-3 or higher capacity circuit.

  • LowOrder_Circuit---Represents a circuit that carries a VC-2 or lower capacity circuit.

    In the simplest case, a LogicalConnection is LayeredOver a single TopologicalLink. Logical connection class relationships in SONET/SDH shows the main relationships between CTPs, PTPs, TopologicalLinks, and LogicalConnections for a simple linear connection.

    Figure 1. Logical connection class relationships in SONET/SDH

    

    The end points of logical connections are represented by CTPs, which are LayeredOver PTP objects. Each CTP object contains the timeslot information for the connection that uses it. Many CTP objects can be LayeredOver each PTP when many low-speed circuits are provisioned on the same higher speed port.