14 Sep
2022
14 Sep
'22
2:14 p.m.
pespin has uploaded this change for review. (
https://gerrit.osmocom.org/c/osmo-gsm-manuals/+/29354 )
Change subject: Document osmux use in Abis interface
......................................................................
Document osmux use in Abis interface
Related: SYS#5987
Change-Id: Ic02d379f35f29f633d0fb14da3597481a0b8b8ba
---
A common/chapters/osmux/mo_call_osmux_abis.msc
A common/chapters/osmux/network_osmux_abis.dot
M common/chapters/osmux/osmux.adoc
3 files changed, 106 insertions(+), 0 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-gsm-manuals refs/changes/54/29354/1
diff --git a/common/chapters/osmux/mo_call_osmux_abis.msc
b/common/chapters/osmux/mo_call_osmux_abis.msc
new file mode 100644
index 0000000..f52d414
--- /dev/null
+++ b/common/chapters/osmux/mo_call_osmux_abis.msc
@@ -0,0 +1,54 @@
+# MO-call with Osmux enable on 3GPP AoIP
+msc {
+ hscale=2;
+ ms [label="MS"], bts [label="OsmoBTS"],
bsc[label="OsmoBSC"], mgw_bsc[label="OsmoMGW(bsc)"],
m_sc[label="MSC"], mgw_msc[label="OsmoMGW(msc)"];
+
+ bsc <- m_sc [label="BSSMAP RESET (with extension IE: Osmux Support)"];
+ bsc -> m_sc [label="BSSMAP RESET ACK (with extension IE: Osmux
Support)"];
+ ...;
+ ms box mgw_msc [label="We assume a SDCCH is already established"];
+ ...;
+
+ ms -> bsc [label="DTAP CM Service Request"];
+ bsc -> m_sc [label="Complete Layer 3 Information DTAP CM Service
Request"];
+
+ # Allocate MGW/MSC Osmux endpoint
+ m_sc -> mgw_msc [label="MGCP CRCX rtpbridge/*@mgw, X-Osmux: *"];
+ mgw_msc box mgw_msc [label="Bind to MGW-local RTP Port (5000)\nAllocate new
endpoint 1"];
+ mgw_msc -> m_sc [label="MGCP CRCX rtpbridge/1@mgw OK (MGW:5000)"];
+
+ bsc <- m_sc [label="BSSAP ASSGN REQ)"];
+ bts <- bsc [label="RSL CHAN ACT"];
+ bts -> bsc [label="RSL CHAN ACT ACK"];
+ ms <- bsc [label="Assignment Command"];
+ ms -> bsc [label="Assignment Complete"];
+ ...;
+
+ # connect BTS RTP with BSC-MGW RTP
+ bsc -> mgw_bsc [label="MGCP CRCX rtpbridge/*@mgw, X-Osmux: *"];
+ mgw_bsc box mgw_bsc [label="Bind to MGW-local Osmux Port (1984)\n\nAllocate new
endpoint 2, MGW's local CID 5"];
+ bsc <- mgw_bsc [label="MGCP CRCX rtpbridge/2@mgw OK (MGW:1984, X-Osmux:
5)"];
+ bts <- bsc [label="IPA CRCX (Extension IE Osmux-CID 5)"];
+ bts box bts [label="Bind to BTS-local Osmux Port (1985), Allocate new BTS's
local CID 7"];
+ bts -> bsc [label="IPA CRCX ACK (BTS:1985, Extension IE Osmux-CID 7)"];
+ bsc -> mgw_bsc [label="MGCP MDCX rtpbridge/2@mgw (BTS:1985, X-Osmux: 7)"];
+ mgw_bsc box mgw_bsc [label="\nConnect to BTS:1985 MGW's remote CID 7"];
+ bsc <- mgw_bsc [label="MGCP CRCX rtpbridge/2@mgw OK (MGW:1984, X-Osmux:
5)"];
+ ...;
+
+ mgw_bsc <- bsc [label="MGCP CRCX rtpbridge/2@mgw (MSC:5000)"];
+ mgw_bsc box mgw_bsc [label="Bind to MGW-local RTP Port (2000)\nConnect to
MSC:5000"];
+ mgw_bsc -> bsc [label="MGCP CRCX rtpbridge/2@mgw OK (MGW:2000)"];
+ ...;
+
+ bsc -> m_sc [label="BSSAP ASSGN CMPL (3GPP AoIP MGW:2000)"];
+ m_sc box m_sc [label="Connect remote RTP to MGW addr from ASSGN CMPL"];
+ m_sc -> mgw_msc [label="MGCP MDCX rtpbridge/1@mgw (MGW:2000)"];
+ m_sc <- mgw_msc [label="MGCP MDCX rtpbridge/1@mgw OK"];
+ ...;
+
+ mgw_bsc <=> mgw_msc [label="RTP Audio MGW:2000 MSC:5000"];
+ bts <=> mgw_bsc [label="Osmux Audio BTS:1985 MGW:1984, CID(uplink):5,
CID(downlink):7"];
+ ms <=> bts [label="Um Audio (bidirectional)"];
+ ms <-> m_sc [label="DTAP CC ALERTING"];
+}
diff --git a/common/chapters/osmux/network_osmux_abis.dot
b/common/chapters/osmux/network_osmux_abis.dot
new file mode 100644
index 0000000..578e0d1
--- /dev/null
+++ b/common/chapters/osmux/network_osmux_abis.dot
@@ -0,0 +1,32 @@
+digraph G {
+ rankdir = LR;
+ subgraph cluster_RAN {
+ OsmoBTS1 [label="OsmoBTS"];
+ OsmoBTS2 [label="OsmoBTS"];
+ OsmoBSC;
+ OsmoMGW [label="OsmoMGW\n(for BSC)"];
+
+ OsmoBTS1 -> OsmoBSC [label="Abis/IP", dir="both"];
+ OsmoBTS2 -> OsmoBSC [label="Abis/IP", dir="both"];
+ OsmoBSC -> OsmoMGW [label="MGCP", dir="both"];
+ { rank = same; OsmoBSC; OsmoMGW }
+
+ OsmoBTS1 -> OsmoMGW [label="Osmux", dir="both", color=red];
+ OsmoBTS2 -> OsmoMGW [label="RTP", dir="both"];
+
+ label = "RAN";
+ }
+ subgraph cluster_CN {
+ OsmoMGW1 [label="OsmoMGW\n(for MSC)"];
+ OsmoMSC [label="MSC\ne.g. OsmoMSC"];
+ Core [label="Other CN Elements"];
+ OsmoMSC -> Core [label="MAP/ISUP/SIP/GSUP", dir="both"];
+ OsmoMSC -> OsmoMGW1 [label="MGCP", dir="both"];
+ { rank = same; OsmoMSC; OsmoMGW1 }
+ OsmoMGW -> OsmoMGW1 [label="RTP", dir="both"];
+ OsmoMGW1 -> Core [label="RTP", dir="both"];
+ label = "CN";
+ }
+
+ OsmoBSC -> OsmoMSC [label="3GPP AoIP\nvia SIGTRAN/STP",
dir="both"];
+}
diff --git a/common/chapters/osmux/osmux.adoc b/common/chapters/osmux/osmux.adoc
index 68d628f..f1e6f87 100644
--- a/common/chapters/osmux/osmux.adoc
+++ b/common/chapters/osmux/osmux.adoc
@@ -18,6 +18,11 @@
OsmoBSCNAT). The MGW attached those components need of course also be aware of
`Osmux` existence in order to properly set up the audio data plane.
+Under some specific circumstances, the operator may decide to set up the network
+so that the satellite link lays in between the BTS and BSC. Hence, use of the
+`Osmux` protocol is also possible between an Osmux capable BTS (like OsmoBTS)
+and OsmoBSC (and its co-located MGW).
+
=== Osmux and NAT
It is quite usual for satellite based links to use NATs, which means any or both
@@ -139,3 +144,18 @@
----
include::mgcp_extension_osmux.adoc[]
+
+=== Abis setup with Osmux
+
+[[fig-network-osmux-aoip]]
+.Sample node diagram of Osmux enabled in the Abis interface
+[graphviz]
+----
+include::network_osmux_abis.dot[]
+----
+
+.MO-call with Osmux enabled on Abis
+[mscgen]
+----
+include::mo_call_osmux_abis.msc[]
+----
--
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Gerrit-Project: osmo-gsm-manuals
Gerrit-Branch: master
Gerrit-Change-Id: Ic02d379f35f29f633d0fb14da3597481a0b8b8ba
Gerrit-Change-Number: 29354
Gerrit-PatchSet: 1
Gerrit-Owner: pespin <pespin(a)sysmocom.de>
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