Explains how simulated capacity represents the effective capacity of network objects, reflecting both configured and operational conditions to guide utilization calculations and planning.
A simulated capacity is a network capacity metric that
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reflects the effective capacity of an object
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takes into account network state, including any failures that may reduce capacity, and
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is represented by the Capacity sim column in the Network Summary tables.
All utilization figures in the Interfaces, Circuits, and Interface Queues tables are calculated based on this value.
The Capacity column shows 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 Edit window. 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.
Simulated capacity calculation rules
There are a few rules to note regarding Capacity sim calculation.
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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. Specify circuit capacities instead of interface capacities to easily modify existing capacities. This is useful for build-out planning.
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If the circuit has no Capacity, then its Capacity sim is the minimum of its constituent interface Capacity values. The Capacity of an interface 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.
The field in the interface's Edit window is Configured capacity, while the column name in the Interfaces table is Capacity.
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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.
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In a LAG interface, if any of the constituent LAG members are operationally down, the interface Capacity sim column shows 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.
If a pair of ports is considered in Capacity sim calculations, both must be operational to be considered.