diff options
Diffstat (limited to 'src/libmsc/msc_a.c')
| -rw-r--r-- | src/libmsc/msc_a.c | 43 |
1 files changed, 21 insertions, 22 deletions
diff --git a/src/libmsc/msc_a.c b/src/libmsc/msc_a.c index c022ee2d4..e8dc58b8a 100644 --- a/src/libmsc/msc_a.c +++ b/src/libmsc/msc_a.c @@ -1389,7 +1389,6 @@ static void msc_a_up_call_assignment_complete(struct msc_a *msc_a, const struct struct rtp_stream *rtps_to_ran = msc_a->cc.call_leg ? msc_a->cc.call_leg->rtp[RTP_TO_RAN] : NULL; const struct gsm0808_speech_codec *codec_if_known = ac->assignment_complete.codec_present ? &ac->assignment_complete.codec : NULL; - const struct codec_mapping *codec_cn; if (!rtps_to_ran) { LOG_MSC_A(msc_a, LOGL_ERROR, "Rx Assignment Complete, but no RTP stream is set up\n"); @@ -1408,27 +1407,27 @@ static void msc_a_up_call_assignment_complete(struct msc_a *msc_a, const struct } if (codec_if_known) { - if (ac->assignment_complete.codec_with_iuup) { - /* FUTURE: soon, we want to tell the MGW to decapsulate IuUP to plain AMR-FR/RTP. So far, - * continue to forward IuUP to the CN. - * - * ran_msg_iu now returns AMR-FR as the assigned codec. If we use that directly, that will - * instruct the MGW to decapsulate IuUP into plain RTP. Let's keep this change to an explicit - * patch, while various codecs patches are still being applied. - * - * So instruct MGW to forward IuUP to CN: - */ - codec_cn = codec_mapping_by_subtype_name("VND.3GPP.IUFP"); - OSMO_ASSERT(codec_cn); - } else { - codec_cn = codec_mapping_by_gsm0808_speech_codec_type(codec_if_known->type); - /* TODO: use codec_mapping_by_gsm0808_speech_codec() to also match on codec_if_known->cfg */ - if (!codec_cn) { - LOG_TRANS(cc_trans, LOGL_ERROR, "Unknown codec in Assignment Complete: %s\n", - gsm0808_speech_codec_type_name(codec_if_known->type)); - call_leg_release(msc_a->cc.call_leg); - return; - } + const struct codec_mapping *codec_cn; + /* For 2G: + * - The Assignment Complete has returned a specific codec (e.g. FR3 for AMR FR). + * - Set this codec at the MGW endpoint facing the RAN. + * - Also set this codec at the MGW endpoint facing the CN -- we require an exact match on both call + * legs. + * - TODO: be aware of transcoding that the MGW is capable of, e.g. AMR octet-aligned to AMR + * bandwidth-efficient... + * + * For 3G: + * - ran_infra->force_mgw_codecs_to_ran sets VND.3GPP.IUFP as single codec at the MGW towards RAN. + * - ran_msg_iu.c always returns FR3 (AMR FR) for the assigned codec. Set that at the MGW towards CN. + * - So the MGW decapsulates IuUP <-> AMR + */ + codec_cn = codec_mapping_by_gsm0808_speech_codec_type(codec_if_known->type); + /* TODO: use codec_mapping_by_gsm0808_speech_codec() to also match on codec_if_known->cfg */ + if (!codec_cn) { + LOG_TRANS(cc_trans, LOGL_ERROR, "Unknown codec in Assignment Complete: %s\n", + gsm0808_speech_codec_type_name(codec_if_known->type)); + call_leg_release(msc_a->cc.call_leg); + return; } /* Update RAN-side endpoint CI from Assignment result -- unless it is forced by the ran_infra, in which |