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8. IANA Considerations

Following the guidelines in [8], the IANA has registered one new SDP attribute:

  • Contact name/email: authors of RFC 5761
  • Attribute name: rtcp-mux
  • Long-form attribute name: RTP and RTCP multiplexed on one port
  • Type of attribute: media level
  • Subject to charset: no

This attribute is used to signal that RTP and RTCP traffic should be multiplexed on a single port (see Section 5 of this memo). It is a property attribute, which does not take a value.

The rules for assignment of RTP RTCP Control Packet Types in the RTP Parameters registry are updated as follows. When assigning RTP RTCP Control Packet types, IANA is requested to assign unused values from the range 200-223 where possible. If that range is fully occupied, values from the range 194-199 may be used, and then values from the ranges 1-191 and 224-254. This improves header validity checking of RTCP packets compared to RTP packets or other unrelated packets. The values 0 and 255 are avoided for improved validity checking relative to random packets since all-zeros and all-ones are common values.

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