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-rw-r--r--doc/manuals/aoip-mgw-options-docinfo.xml10
-rw-r--r--doc/manuals/aoip-mgw-options.adoc30
-rw-r--r--doc/manuals/mgw/osmo-bsc-new-mgw-e1.msc4
-rw-r--r--doc/manuals/mgw/osmo-bsc-new-mgw.msc4
4 files changed, 33 insertions, 15 deletions
diff --git a/doc/manuals/aoip-mgw-options-docinfo.xml b/doc/manuals/aoip-mgw-options-docinfo.xml
index 080959443..4cec92fa7 100644
--- a/doc/manuals/aoip-mgw-options-docinfo.xml
+++ b/doc/manuals/aoip-mgw-options-docinfo.xml
@@ -7,6 +7,14 @@
Initial version of the proposal for internal discussion.
</revremark>
</revision>
+ <revision>
+ <revnumber>1.0</revnumber>
+ <date>November 2020</date>
+ <authorinitials>Harald Welte</authorinitials>
+ <revremark>
+ Update with changes on what was actually implemented in recent years; change from future to past tense.
+ </revremark>
+ </revision>
</revhistory>
<authorgroup>
@@ -24,7 +32,7 @@
</authorgroup>
<copyright>
- <year>2017</year>
+ <year>2017-2020</year>
<holder>sysmocom - s.f.m.c. GmbH</holder>
</copyright>
diff --git a/doc/manuals/aoip-mgw-options.adoc b/doc/manuals/aoip-mgw-options.adoc
index 124c03fda..62163ccc4 100644
--- a/doc/manuals/aoip-mgw-options.adoc
+++ b/doc/manuals/aoip-mgw-options.adoc
@@ -5,8 +5,8 @@
This document serves as a paper to illustrate the different
configurations of OsmoBSC in terms of integration with BTSs and MSCs.
-The document should accompany us in the 2017 development cycle which
-includes the _death of the NITB_, i.e. the move away from OsmoNITB to
+The document was created ahead of the 2017 development cycle which
+included the _death of the NITB_, i.e. the move away from OsmoNITB to
having OsmoBSC in all configurations, whether with a
proprietary/external MSC or with OsmoMSC.
@@ -24,8 +24,13 @@ such as
=== Classic GSM RAN with E1 based Abis and E1 A
-This configuration was actually never supported by OpenBSC, as E1 BTS
-support was so far for NITB only, but not for OsmoBSC.
+This is how GSM was originally specified when it was introduced: E1/T1
+circuits on all interfaces, no IP anywhere.
+
+This configuration was actually never supported by OpenBSC, as E1
+support was always only on the Abis side (OpenBSC, OsmoNITB and today OsmoBSC).
+
+We never supported A interface over E1. It could be done if there was a need.
[mscgen]
----
@@ -53,11 +58,11 @@ Release 7 of 3GPP included an official specification on how an
interoperable A-over-IP (AoIP) interface shall look like.
As more modern MSCs at operators tend to favor implementing 3GPP AoIP
-rather than the proprietary SCCPlite based A interface, it becomes
+rather than the proprietary SCCPlite based A interface, it became
necessary for OsmoBSC to support this.
At the same time, for compatibility reasons, the classic SCCPlite
-support shall be kept, if possible with reasonable effort.
+support is kept in OsmoBSC as a configuration option.
[mscgen]
----
@@ -65,11 +70,16 @@ include::{srcdir}/mgw/osmo-bsc-new-mgw.msc[]
----
-=== OsmoBSC 2017+: 3GPP AoIP + Abis/E1
+=== OsmoBSC 2020+: 3GPP AoIP + Abis/E1
+
+Since OsmoNITB was deprecated in 2017, and OsmoBSC only supported Abis/IP,
+we temporarily lost the ability to use classic E1 based BTSs. In 2020,
+we re-introduced and re-tested the support of Abis/E1.
-Since OsmoNITB will soon be deprecated, we will use OsmoBSC in all
-Osmocom GSM ntework setups, requiring the support for classic E1/T1
-based BTSs from OsmoBSC.
+Fro the control plane of Abis (RSL, OML) the E1 support via libosmo-abis
+never really ceased to exist. But for the user plane, E1 support had to be
+introduced to osmo-mgw, and osmo-bsc needed to be taught how to configure
+E1 endpoints at the MGW. The related call flow for such setups looks like this:
[mscgen]
----
diff --git a/doc/manuals/mgw/osmo-bsc-new-mgw-e1.msc b/doc/manuals/mgw/osmo-bsc-new-mgw-e1.msc
index 04b114fff..676948cdd 100644
--- a/doc/manuals/mgw/osmo-bsc-new-mgw-e1.msc
+++ b/doc/manuals/mgw/osmo-bsc-new-mgw-e1.msc
@@ -1,8 +1,8 @@
# MO-Call with E1 BTS + OsmoBSC with true 3GPP AoIP (planned
-# osmo-bsc_mgcp has to be extended to true MGW functionality!
+# osmo-mgw has to be extended to true MGW functionality!
msc {
hscale=2;
- ms [label="MS"], bts [label="E1 BTS"], bsc[label="OsmoBSC"], mgcp[label="osmo-bsc_mgcp"], m_sc[label="MSC"];
+ ms [label="MS"], bts [label="E1 BTS"], bsc[label="OsmoBSC"], mgcp[label="osmo-mgw"], m_sc[label="MSC"];
ms box m_sc [label="We assume a SDCCH is already established"];
...;
diff --git a/doc/manuals/mgw/osmo-bsc-new-mgw.msc b/doc/manuals/mgw/osmo-bsc-new-mgw.msc
index e618bb721..d6450bd22 100644
--- a/doc/manuals/mgw/osmo-bsc-new-mgw.msc
+++ b/doc/manuals/mgw/osmo-bsc-new-mgw.msc
@@ -1,7 +1,7 @@
-# MO-Call with OsmoBTS + OsmoBSC with true 3GPP AoIP (planned)
+# MO-Call with OsmoBTS + OsmoBSC with true 3GPP AoIP
msc {
hscale=2;
- ms [label="MS"], bts [label="OsmoBTS"], bsc[label="OsmoBSC"], mgcp[label="osmo-bsc_mgcp"], m_sc[label="MSC"];
+ ms [label="MS"], bts [label="OsmoBTS"], bsc[label="OsmoBSC"], mgcp[label="OsmoMGW"], m_sc[label="MSC"];
ms box m_sc [label="We assume a SDCCH is already established"];
...;