[BCP229]   Best Current Practice 229,
              <https://www.rfc-editor.org/info/bcp229>.
              At the time of writing, this BCP comprises the following:

              Abrahamsson, M., Chown, T., Giuliano, L., and T. Eckert,
              "Deprecating Any-Source Multicast (ASM) for Interdomain
              Multicast", BCP 229, RFC 8815, DOI 10.17487/RFC8815,
              August 2020, <https://www.rfc-editor.org/info/rfc8815>.