WAE Design uses demands to simulate traffic between source and destination endpoints within a network. Each demand has a specified amount of traffic.

By default, an up-to-date simulation of an open plan is always available. Any change in the plan that affects or invalidates the current simulation automatically triggers a resimulation. Types of changes that result in resimulations are those that would typically affect routing in a network.

• Changes in topology, such as adding and deleting objects or changing explicit paths.

• Changes to an object’s state, such as failing an object or making it inactive.

• Changes in numerous properties, such as metrics, capacities, and delay.

To toggle automatic resimulation on and off, do one of the following:

• Click the drop-down arrow next to the Simulation On/Off icon (white arrow in green circle) in the Visualization toolbar. Check or uncheck Auto resimulate to toggle it on or off.

  

• Choose Tools > Simulator > Switch On/Switch Off.

The state of an object affects simulation and determines whether an object is operational.

• Failed State—Identifies whether the object is failed.

• Active State—Identifies whether the object is available for use in the simulated network. For example, an object might be unavailable because it has been set administratively down.

• Operational State—Identifies whether an object is operational. For example, an object might be non-operational because it is failed, is inactive, or because other objects on which it depends are not operational.

The Failed and Active columns in the tables show a visual representation of their status. Likewise, you can show the Operational column to show the calculated operational state. In each column, T means the object is in that state and F means it is not. Note that the T or F for Active state in the Interfaces table is reflective of the associated circuit. The plot shows graphical representations of these states with crosses of various colors and fills.

The Capacity column displays the configured physical capacity of interfaces, circuits, ports, and port circuits. Each circuit, port, and port circuit has a physical capacity that you can set in the Capacity field of the Properties dialog box. The interfaces have a configurable capacity that you can set in the Configured Capacity field. From these properties, a simulated capacity (Capacity Sim) is derived for each object.

The Capacity Sim column is the calculated capacity of the object given the state of the network, which could include failures that reduce capacity. All utilization figures in the Interfaces, Circuits, and Interface Queues tables are calculated based on this Capacity Sim value. When referencing the Capacity Sim value, there are a few rules to note regarding its calculation.

• If a circuit’s Capacity is specified, this becomes the Capacity Sim of the circuit, and all other capacities (interface and constituent port capacities) are ignored. Specifying circuit capacities (rather than interface capacities) is the simplest way to modify existing capacities, which is useful, for example, for build-out planning.

• If the circuit has no Capacity, then its Capacity Sim is the minimum of its constituent interface Capacity values. The interface Capacity is the sum of the Capacity values of the associated ports. If the interface has no ports or if the ports have no Capacity, it is the same as the interface's Configured Capacity property. (Note the field in the interface Property dialog box is “Configured Capacity,” while the column name in the Interfaces table is “Capacity.”)

• If two ports are connected explicitly by a port circuit, the Capacity Sim of the port circuit is set to the minimum capacity of the three, which effectively negotiates down the capacity of each side of the connection.

• If two ports are connected implicitly by an L1 circuit, the Capacity Sim of the two ports is set to the minimum Capacity of the two, which again, effectively negotiates down the capacity of each side of the connection.

• In a LAG interface, if any of the constituent LAG members are operationally down, the interface Capacity Sim column displays a value that is reduced by the aggregate capacity of all the LAG members that are down. For example, if a 1000-Mbps port of a four-port 4000-Mbps LAG is operationally down, the simulated capacity for that LAG interface becomes 3000 Mbps.

  Note	If a pair of ports is considered in Capacity Sim calculations, both must be operational to be considered.

Both Delay and Distance are properties that can be set in the circuit Properties dialog box. To automate the process of setting these, use the Latency and Distance Initializer.

All WAE Design delay calculations that use the L3 circuit delay, such as Metric Optimization, use the Delay Sim value.