http://www.rfc-editor.org/rfc/rfc7761.txt
RFC 7761: Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised), B. Fenner, M. Handley, H. Holbrook, I. Kouvelas, R. Parekh, Z. Zhang, L. Zheng2016-03-01T23:00:00-00:00This document obsoletes RFC 4601 by replacing it, addresses the errata filed against it, removes the optional (*,*,RP), PIM Multicast Border Router features and authentication using IPsec that lack sufficient deployment experience (see Appendix A), and moves the PIM specification to Internet Standard.