http://www.rfc-editor.org/rfc/rfc8050.txt
RFC 8050: Multi-Threaded Routing Toolkit (MRT) Routing Information Export Format with BGP Additional Path Extensions, C. Petrie, T. King2017-05-01T23:00:00-00:00This document extends the Multi-threaded Routing Toolkit (MRT) export format for Border Gateway Protocol (BGP) routing information by supporting the advertisement of multiple paths in BGP extensions.