Filtering Adj-Rib-In and Adj-Rib-Out to BMP receivers

Filtering RIBs in BMP (BGP Monitoring Protocol) can be desirable for several use-cases like, for example, limiting the amount of data a collector station has to process or allow a sender to export only a certain afi/safi of interest. This document defines a light way to inform a collector station that a Adj-Rib-In / Adj-Rib-Out data feed is being filtered.