If the network includes virtual routers, the count must include their interfaces in addition to the physical ports and interfaces. A virtual router is a software emulation of a router implemented within a physical router or switch.

Calculate the estimated number of managed ports and interfaces using the ratios of 90 percent managed for interfaces and 5 percent managed for ports:

Estimated number of managed ports and interfaces

=

90 percent interfaces

+

5 percent ports

For example, if the network has 2,300 interfaces and 18,000 ports, then calculate the managed ports and interfaces as follows:

Estimated number of managed ports and interfaces

=

90 percent interfaces

+

5 percent ports

=

((90/100) * 2,300)

+

((5/100) * 18,000)

=

2,070

+

900

=

2,970

All values that were less than one were rounded up in these calculations.