Atlassian Atlassian CoSMo Privacy Enhanced RTP Conferenceing allows middle boxes (MDs) to overwrite a certain set of fields in RTP packets, as long as they preserve their original values in the Original Header Block (OHB). This draft discusses the option of extending the OHB so that it would also include the RTP timestamp and Synchornization Source identifier (SSRC) within the set of fields an SSRC can modify.