neels has uploaded this change for review. (
https://gerrit.osmocom.org/c/osmo-bsc/+/31616
)
Change subject: doc: add codec_resolution.msc
......................................................................
doc: add codec_resolution.msc
Illustrate the various factors that influence picking a codec for a 2G
voice call in osmo-bsc.
Change-Id: I3d63a0d587a43fc18ea54b3982800b19b4d50a08
---
M doc/Makefile.am
A doc/codec_resolution.msc
2 files changed, 61 insertions(+), 0 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/16/31616/1
diff --git a/doc/Makefile.am b/doc/Makefile.am
index d68b3f6..32d06c1 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -14,6 +14,7 @@
$(builddir)/handover-inter-bsc-in.png \
$(builddir)/mgw-endpoint.png \
$(builddir)/location_services_ta.png \
+ $(builddir)/codec_resolution.png \
$(NULL)
dot: \
diff --git a/doc/codec_resolution.msc b/doc/codec_resolution.msc
new file mode 100644
index 0000000..4550448
--- /dev/null
+++ b/doc/codec_resolution.msc
@@ -0,0 +1,48 @@
+msc {
+ hscale="1.7";
+
ms[label="MS/BTS"],cfg[label="osmo-bsc.cfg"],bsc[label="osmo-bsc"],__msc[label="MSC"],sip[label="SIP"];
+
+ ms => bsc [label="EST IND / Compl L3"];
+ cfg => bsc [label="'msc 0'\n'codec-list fr3 hr3 fr2 fr1
hr1'"];
+ bsc rbox bsc [label="build Speech Codec
List\ngen_bss_supported_codec_list()"];
+ bsc => __msc [label="Compl L3"];
+ bsc note __msc [label="Speech Codec List (BSS Supported)\n{GSM0808_SCT_FR3 +
AMR-cfg,\nGSM0808_SCT_HR3 +
AMR-cfg,\nGSM0808_SCT_FR2,\nGSM0808_SCT_FR1,\nGSM0808_SCT_HR1}"];
+ --- [label="AMR-cfg:"];
+ bsc note __msc [label="S0-S15: 16bit flags\nS0 = 1: 4.75 ---- ---- ---- ---- ----
---- ----\nS1 = 1: 4.75 ---- 5.90 ---- 7.40 ---- ---- 12.2\nS2 = 1: ---- ---- 5.90 ----
---- ---- ---- ----\nS3 = 1: ---- ---- ---- 6.70 ---- ---- ---- ----\nS4 = 1: ---- ----
---- ---- 7.40 ---- ---- ----\nS5 = 1: ---- ---- ---- ---- ---- 7.95 ---- ----\nS6 = 1:
---- ---- ---- ---- ---- ---- 10.2 ----\nS7 = 1: ---- ---- ---- ---- ---- ---- ----
12.2\n\nS8 = 1: 4.75 ---- 5.90 ---- ---- ---- ---- ----\nS9 = 1: 4.75 ---- 5.90 6.70 ----
---- ---- ----\nS10= 1: 4.75 ---- 5.90 6.70 7.40 ---- ---- ----\nS11= 1: ---- ---- ----
---- ---- ---- ---- ----\nS12= 1: 4.75 ---- 5.90 6.70 ---- ---- 10.2 ----\nS13= 1: ----
---- ---- ---- ---- ---- ---- ----\nS14= 1: 4.75 ---- 5.90 ---- ---- 7.95 ---- 12.2\nS15=
1: ---- ---- ---- ---- ---- ---- ---- ----\n\n3GPP TS 28.062 Table 7.11.3.1.3-2:
\"Preferred Configurations\",\nsome removed as specified in 3GPP TS 48.008
3.2.2.103"];
+
+ cfg => bsc [label="'bts 0'\n'amr tch-x modes 0 2 4 7'"];
+ bsc rbox bsc [label="convert AMR modes to\nbts-S0-S15"];
+ cfg => bsc [label="'msc 0'\n'amr-config 4_75k allowed'"];
+ bsc rbox bsc [label="convert AMR modes to\nmsc-S0-S15"];
+ bsc => __msc [label="Compl L3 Speech Codec List:\nbitwise AND:\nbts-S0-S15
& msc-S0-S15"];
+ ---;
+
+ ms => __msc [label="Bearer Capabilities"];
+ __msc <= sip [label="SDP"];
+ __msc note sip [label="m=audio 12345 RTP/AVP 112 3 111 110\na=rtpmap:112
AMR/8000\na=fmtp:112 mode-set=0,2,4,7\na=rtpmap:3 GSM/8000\na=rtpmap:111
GSM-HR-08/8000\na=rtpmap:110 GSM-EFR/8000"];
+
+ __msc rbox __msc [label="combine:\nBSC: Speech Codec List\nMS: Bearer Cap\nSIP:
SDP"];
+
+ bsc <= __msc [label="BSSMAP Assignment Request\ncontains\nChannel Type\nSpeech
Codec List (MSC Preferred)"];
+ bsc note __msc [label="Channel Type\nChannel Rate And Type:\n- [prefer] full
rate\n- [prefer] half rate\n- indicated by Permitted Speech list\nPermitted Speech
[1..9]:\n{GSM0808_PERM_FR3,\nGSM0808_PERM_HR3,\nGSM0808_PERM_FR2,\nGSM0808_PERM_FR1,\nGSM0808_PERM_HR1}"];
+ bsc note __msc [label="Speech Codec List (MSC Preferred)\n{GSM0808_SCT_FR3 +
AMR-cfg,\nGSM0808_SCT_HR3 +
AMR-cfg,\nGSM0808_SCT_FR2,\nGSM0808_SCT_FR1,\nGSM0808_SCT_HR1}"];
+
+ cfg => bsc [label="'msc 0'\n'codec-list fr3 hr3 fr2 fr1
hr1'"];
+ cfg => bsc [label="'bts 0'\n'phys_chan_cfg TCH/F'"];
+ cfg => bsc [label="'bts 0'\n'codec-support amr efr fr
hr'"];
+
+ cfg rbox bsc [label="combine:\n'msc 0' 'codec-list fr3 hr3 fr2 fr1
hr1'\n'bts 0' 'phys_chan_cfg TCH/F'\n'bts 0'
'codec-support amr efr fr hr'\nMSC: Channel Type\nMSC: Speech Codec List (MSC
Preferred)\n=>\n{GSM48_CMODE_SPEECH_AMR, FR, S0-S15},\n{GSM48_CMODE_SPEECH_AMR, HR,
S0-S15}"];
+
+ cfg => bsc [label="'bts 0'\n'amr tch-x bts threshold'\n'amr
tch-x bts hysteresis'"];
+ ms <= bsc [label="RSL CHANnel ACTIVation"];
+ ms note bsc [label="Channel Rate and Type: Full/Half rate\nSpeech Coding Algorithm
Version: 3 (=AMR)\nMultiRate Configuration:\n- 4.75 | 5.90 | 7.40 | 12.2\n- Threshold /
Hysteresis x 3"];
+ cfg => bsc [label="'bts 0'\n'amr tch-x ms threshold'\n'amr
tch-x ms hysteresis'"];
+ ms <= bsc [label="RSL Assignment Command"];
+ ms note bsc [label="Channel Description: TCH/F\nSpeech Coding Algorithm Version: 3
(=AMR)\nMultiRate Configuration:\n- 4.75 | 5.90 | 7.40 | 12.2\n- Threshold / Hysteresis x
3"];
+
+ bsc => __msc [label="BSSMAP Assignment Complete"];
+ bsc note __msc [label="Chosen Channel: Speech, Full Rate\nSpeech Version (Chosen):
FR3\nSpeech Codec (Chosen): FR AMR, S0-S15"];
+
+ __msc => sip [label="SDP (optional)"];
+ __msc note sip [label="m=audio 12345 RTP/AVP 112\na=rtpmap:112
AMR/8000\na=fmtp:112 mode-set=0,2,4,7"];
+}
--
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Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: I3d63a0d587a43fc18ea54b3982800b19b4d50a08
Gerrit-Change-Number: 31616
Gerrit-PatchSet: 1
Gerrit-Owner: neels <nhofmeyr(a)sysmocom.de>
Gerrit-MessageType: newchange