/**
* PortGroup is a simple data-structure to represent any arbitrary group of
* ports on a Switch (that is represented using its switch-ID).
/**
* PortGroup is a simple data-structure to represent any arbitrary group of
* ports on a Switch (that is represented using its switch-ID).
* PortGroup is used by PortGroupProvider application to signal a set of ports
* that represent a configured PortGroupConfig.
* PortGroup is used by PortGroupProvider application to signal a set of ports
* that represent a configured PortGroupConfig.