RFC 1889 RTP January 1996 5.3 Profile-Specific Modifications to the RTP Header..... 14 5.3.1 RTP Header Extension ................................ 14 6. RTP Control Protocol -- RTCP ........................ 15 6.1 RTCP Packet Format .................................. 17 6.2 RTCP Transmission Interval .......................... 19 6.2.1 Maintaining the number of session members ........... 21 6.2.2 Allocation of source description bandwidth .......... 21 6.3 Sender and Receiver Reports ......................... 22 6.3.1 SR: Sender report RTCP packet ....................... 23 6.3.2 RR: Receiver report RTCP packet ..................... 28 6.3.3 Extending the sender and receiver reports ........... 29 6.3.4 Analyzing sender and receiver reports ............... 29 6.4 SDES: Source description RTCP packet ................ 31 6.4.1 CNAME: Canonical end-point identifier SDES item ..... 32 6.4.2 NAME: User name SDES item ........................... 34 6.4.3 EMAIL: Electronic mail address SDES item ............ 34 6.4.4 PHONE: Phone number SDES item ....................... 34 6.4.5 LOC: Geographic user location SDES item ............. 35 6.4.6 TOOL: Application or tool name SDES item ............ 35 6.4.7 NOTE: Notice/status SDES item ....................... 35 6.4.8 PRIV: Private extensions SDES item .................. 36 6.5 BYE: Goodbye RTCP packet ............................ 37 6.6 APP: Application-defined RTCP packet ................ 38 7. RTP Translators and Mixers .......................... 39 7.1 General Description ................................. 39 7.2 RTCP Processing in Translators ...................... 41 7.3 RTCP Processing in Mixers ........................... 43 7.4 Cascaded Mixers ..................................... 44 8. SSRC Identifier Allocation and Use .................. 44 8.1 Probability of Collision ............................ 44 8.2 Collision Resolution and Loop Detection ............. 45 9. Security ............................................ 49 9.1 Confidentiality ..................................... 49 9.2 Authentication and Message Integrity ................ 50 10. RTP over Network and Transport Protocols ............ 51 11. Summary of Protocol Constants ....................... 51 11.1 RTCP packet types ................................... 52 11.2 SDES types .......................................... 52 12. RTP Profiles and Payload Format Specifications ...... 53 A. Algorithms .......................................... 56 A.1 RTP Data Header Validity Checks ..................... 59 A.2 RTCP Header Validity Checks ......................... 63 A.3 Determining the Number of RTP Packets Expected and Lost ................................................ 63 A.4 Generating SDES RTCP Packets ........................ 64 A.5 Parsing RTCP SDES Packets ........................... 65 A.6 Generating a Random 32-bit Identifier ............... 66 A.7 Computing the RTCP Transmission Interval ............ 68 Schulzrinne, et al Standards Track