BGP is a path vector protocol so traditionally it only receives information from its direct peers. Community strings are for sending targeted info to a distant

BGP is a path vector protocol so traditionally it only receives information from its direct peers. Community strings are for sending targeted info to a distant (or close) autonomous system, enabling you to effect mutually agreed upon changes in that AS. With a larger number if bytes available in a community strings it enables us to use community strings to convey a more complex set of instructions.