Each Entry represents a conceptual row in civplsBgpExtRTTable
and provides the information about the value of the RT being used by BGP.
Depending on the value of civplsBgpExtRTType, an RT might be exported or
imported or both. Every VPLS, which uses auto-discovery for finding peer
nodes, can import and export multiple RTs. This representation allows
support for hierarchical VPLS. A row is created by the operator or agent
prior to autodiscovery.