[BCP108]   Best Current Practice 108,
              <https://www.rfc-editor.org/info/bcp108>.
              At the time of writing, this BCP comprises the following:

              Stephan, E., "IP Performance Metrics (IPPM) Metrics
              Registry", BCP 108, RFC 4148, DOI 10.17487/RFC4148, August
              2005, <https://www.rfc-editor.org/info/rfc4148>.