What is the total data rate when Siren is encapsulated within RTP?
The bit rate will vary once encapsulated in RTP; the Siren payload is not treated differently than another codec or stream, and so consequently the tabulation will be specific to the network and the application. However, the RTP payload for G.722.1 and G.722.1C is specified in ITU-T Recommendation G.722.1 Annex A, and also specified in IETF RFC 3047 and draft-ietf-avt-rfc3047-bis-04 which updates RFC 3047 adding support for G.722.1C.