Hello! In my - slightly extended - simple_pjsua I added codec prioritisation the following way: codec_id = pj_str("GSM/8000"); status = pjsua_codec_set_priority(&codec_id, PJMEDIA_CODEC_PRIO_NORMAL+12); codec_id = pj_str("speex/8000"); status = pjsua_codec_set_priority(&codec_id, PJMEDIA_CODEC_PRIO_NORMAL+11); codec_id = pj_str("iLBC/8000"); status = pjsua_codec_set_priority(&codec_id, PJMEDIA_CODEC_PRIO_NORMAL+10); codec_id = pj_str("speex/16000"); status = pjsua_codec_set_priority(&codec_id, PJMEDIA_CODEC_PRIO_NORMAL+9); this way it should use GSM/8000 codec to speak with the server. Despite of the fact I could do traffic measurements speaking a measured amount of time this way, how is the canonical way to calculate the amount of traffic going through my network interface generally? Is this generally 8kbit/s doubled due tue incoming traffic (assumed incoming codec is the same) plus some overhead (how much is "some")? Kind Regards, Konsti -- Konstantin Kletschke track IT GmbH Hin?berstra?e 8 D-30175 Hannover fon +49 511 3809890 fax +49 511 3809899 Gesch?ftsf?hrer: Thilo von Usslar Amtsgericht Hannover HRB 60983 Steuer Nr.: 2325 02520523667 Ust-IdNr.: DE228892 503