<p>daniel has uploaded this change for <strong>review</strong>.</p><p><a href="https://gerrit.osmocom.org/c/osmo-sgsn/+/20281">View Change</a></p><pre style="font-family: monospace,monospace; white-space: pre-wrap;">gbproxy-usermanual: Explain BSSGP/BVC handling<br><br>Related: SYS#5005<br>Change-Id: I383fcd3864a94177f13909c6b8c15648900d3201<br>---<br>A doc/manuals/chapters/gbproxy-details.adoc<br>M doc/manuals/chapters/gbproxy-overview.adoc<br>M doc/manuals/osmogbproxy-usermanual.adoc<br>3 files changed, 121 insertions(+), 5 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;">git pull ssh://gerrit.osmocom.org:29418/osmo-sgsn refs/changes/81/20281/1</pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/doc/manuals/chapters/gbproxy-details.adoc b/doc/manuals/chapters/gbproxy-details.adoc</span><br><span>new file mode 100644</span><br><span>index 0000000..f77d40c</span><br><span>--- /dev/null</span><br><span>+++ b/doc/manuals/chapters/gbproxy-details.adoc</span><br><span>@@ -0,0 +1,113 @@</span><br><span style="color: hsl(120, 100%, 40%);">+[[chapter_details]]</span><br><span style="color: hsl(120, 100%, 40%);">+== Proxy details</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+=== BVC handling</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+This section describes in more detail how BVCs are handled in OsmoGbProxy</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+If a BSS connects to OsmoGbProxy while the SGSN is not available it will</span><br><span style="color: hsl(120, 100%, 40%);">+acknowledge the BVC RESET on the signalling BVC, but ignore other messages</span><br><span style="color: hsl(120, 100%, 40%);">+(especially any PTP BVC RESET).</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+.BSS connects to OsmoGbProxy</span><br><span style="color: hsl(120, 100%, 40%);">+[mscgen]</span><br><span style="color: hsl(120, 100%, 40%);">+----</span><br><span style="color: hsl(120, 100%, 40%);">+msc {</span><br><span style="color: hsl(120, 100%, 40%);">+ hscale="1.8";</span><br><span style="color: hsl(120, 100%, 40%);">+ bss1 [label="BSS1"], bss2 [label="BSS2"], gbproxy [label="GbProxy"], sgsn [label="SGSN"];</span><br><span style="color: hsl(120, 100%, 40%);">+ bss1 <=> gbproxy [label="NS link available"];</span><br><span style="color: hsl(120, 100%, 40%);">+ bss1 => gbproxy [label="BVC RESET (BVCI=0)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy => bss1 [label="BVC RESET ACK"];</span><br><span style="color: hsl(120, 100%, 40%);">+ bss1 -x gbproxy [label="PTP BVC RESET (ignored)"];</span><br><span style="color: hsl(120, 100%, 40%);">+}</span><br><span style="color: hsl(120, 100%, 40%);">+----</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+As soon as the SGSN is reachable through NS OsmoGbProxy will send a BVC RESET</span><br><span style="color: hsl(120, 100%, 40%);">+to the signalling BVC towards the SGSN. After that completes it will reset the</span><br><span style="color: hsl(120, 100%, 40%);">+signalling BVC of all BSS connections. At this point the BSS will send a BVC</span><br><span style="color: hsl(120, 100%, 40%);">+RESET for its PTP BVCs which will be forwarded to the SGSN, similarly the PTP</span><br><span style="color: hsl(120, 100%, 40%);">+BVC RESET ACK from the SGSN will be sent back to the BSS.</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+.SGSN connection to OsmoGbProxy</span><br><span style="color: hsl(120, 100%, 40%);">+[mscgen]</span><br><span style="color: hsl(120, 100%, 40%);">+----</span><br><span style="color: hsl(120, 100%, 40%);">+msc {</span><br><span style="color: hsl(120, 100%, 40%);">+ hscale="1.8";</span><br><span style="color: hsl(120, 100%, 40%);">+ bss1 [label="BSS1"], bss2 [label="BSS2"], gbproxy [label="GbProxy"], sgsn [label="SGSN"];</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy <=> sgsn [label="NS link available"];</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy => sgsn [label="BVC RESET (BVCI=0)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ sgsn => gbproxy [label="BVC RESET ACK"];</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy => bss1 [label="BVC RESET (BVCI=0)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ bss1 => gbproxy [label="BVC RESET ACK"];</span><br><span style="color: hsl(120, 100%, 40%);">+ bss1 box bss1 [label="PTP BVCs need to be reset"];</span><br><span style="color: hsl(120, 100%, 40%);">+ bss1 => gbproxy [label="PTP BVC RESET (BVCI=x)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy => sgsn [label="PTP BVC RESET (BVCI=x)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ sgsn => gbproxy [label="PTP BVC RESET ACK (BVCI=x)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy => bss1 [label="PTP BVC RESET ACK (BVCI=x)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ bss2 <=> sgsn [label="BVCI x established"];</span><br><span style="color: hsl(120, 100%, 40%);">+}</span><br><span style="color: hsl(120, 100%, 40%);">+----</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+The communication on the PTP BVC will then be forwarded between the BSS and the</span><br><span style="color: hsl(120, 100%, 40%);">+SGSN.</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+If a BSS connects while the SGSN is up the PTP BVC RESET will directly be</span><br><span style="color: hsl(120, 100%, 40%);">+forwarded.</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+.BSS connects to OsmoGbProxy</span><br><span style="color: hsl(120, 100%, 40%);">+[mscgen]</span><br><span style="color: hsl(120, 100%, 40%);">+----</span><br><span style="color: hsl(120, 100%, 40%);">+msc {</span><br><span style="color: hsl(120, 100%, 40%);">+ hscale="1.8";</span><br><span style="color: hsl(120, 100%, 40%);">+ bss1 [label="BSS1"], bss2 [label="BSS2"], gbproxy [label="GbProxy"], sgsn [label="SGSN"];</span><br><span style="color: hsl(120, 100%, 40%);">+ bss2 <=> gbproxy [label="NS link available"];</span><br><span style="color: hsl(120, 100%, 40%);">+ bss2 => gbproxy [label="BVC RESET (BVCI=0)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy => bss2 [label="BVC RESET ACK"];</span><br><span style="color: hsl(120, 100%, 40%);">+ bss2 => gbproxy [label="PTP BVC RESET (BVCI=y)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy => sgsn [label="PTP BVC RESET (BVCI=y)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ sgsn => gbproxy [label="PTP BVC RESET ACK (BVCI=y)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy => bss2 [label="PTP BVC RESET ACK (BVCI=y)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ bss2 <=> sgsn [label="BVCI y established"];</span><br><span style="color: hsl(120, 100%, 40%);">+}</span><br><span style="color: hsl(120, 100%, 40%);">+----</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+If OsmoGbProxy looses the connection to the SGSN it will reset the signalling</span><br><span style="color: hsl(120, 100%, 40%);">+BVC of all BSS connections. This ensures that the BSS will not send traffic</span><br><span style="color: hsl(120, 100%, 40%);">+over a PTP BVC before its reset procedure has been completed.</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+.SGSN connection fails</span><br><span style="color: hsl(120, 100%, 40%);">+[mscgen]</span><br><span style="color: hsl(120, 100%, 40%);">+----</span><br><span style="color: hsl(120, 100%, 40%);">+msc {</span><br><span style="color: hsl(120, 100%, 40%);">+ hscale="1.8";</span><br><span style="color: hsl(120, 100%, 40%);">+ bss1 [label="BSS1"], bss2 [label="BSS2"], gbproxy [label="GbProxy"], sgsn [label="SGSN"];</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy <=> sgsn [label="NS link fails"];</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy => bss1 [label="BVC RESET (BVCI=0)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy => bss2 [label="BVC RESET (BVCI=0)"];</span><br><span style="color: hsl(120, 100%, 40%);">+}</span><br><span style="color: hsl(120, 100%, 40%);">+----</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+When the connection to the SGSN is eventually restored the signalling BVC</span><br><span style="color: hsl(120, 100%, 40%);">+between OsmoGbProxy and SGSN will be reset.</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+After that completes OsmoGbProxy will reset the signalling BVC on all BSS NS</span><br><span style="color: hsl(120, 100%, 40%);">+connections and forward the PTP BVC RESET messages.</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+.SGSN connection restored</span><br><span style="color: hsl(120, 100%, 40%);">+[mscgen]</span><br><span style="color: hsl(120, 100%, 40%);">+----</span><br><span style="color: hsl(120, 100%, 40%);">+msc {</span><br><span style="color: hsl(120, 100%, 40%);">+ hscale="1.8";</span><br><span style="color: hsl(120, 100%, 40%);">+ bss1 [label="BSS1"], bss2 [label="BSS2"], gbproxy [label="GbProxy"], sgsn [label="SGSN"];</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy <=> sgsn [label="NS link available"];</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy => sgsn [label="BVC RESET (BVCI=0)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ sgsn => gbproxy [label="BVC RESET ACK"];</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy => bss1 [label="BVC RESET (BVCI=0)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ bss1 => gbproxy [label="BVC RESET ACK"];</span><br><span style="color: hsl(120, 100%, 40%);">+ bss1 box bss1 [label="PTP BVCs need to be reset"];</span><br><span style="color: hsl(120, 100%, 40%);">+ gbproxy => bss2 [label="BVC RESET (BVCI=0)"];</span><br><span style="color: hsl(120, 100%, 40%);">+ bss2 => gbproxy [label="BVC RESET ACK"];</span><br><span style="color: hsl(120, 100%, 40%);">+ bss2 box bss2 [label="PTP BVCs need to be reset"];</span><br><span style="color: hsl(120, 100%, 40%);">+}</span><br><span style="color: hsl(120, 100%, 40%);">+----</span><br><span>diff --git a/doc/manuals/chapters/gbproxy-overview.adoc b/doc/manuals/chapters/gbproxy-overview.adoc</span><br><span>index 580afae..1564157 100644</span><br><span>--- a/doc/manuals/chapters/gbproxy-overview.adoc</span><br><span>+++ b/doc/manuals/chapters/gbproxy-overview.adoc</span><br><span>@@ -1,18 +1,18 @@</span><br><span> [[chapter_overview]]</span><br><span> == Overview</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">-=== About OsmoGbPROXY</span><br><span style="color: hsl(120, 100%, 40%);">+=== About OsmoGbProxy</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">-OsmoGbPROXY is the Osmocom proxy for the 3GPP Gb interface. The Gb</span><br><span style="color: hsl(120, 100%, 40%);">+OsmoGbProxy is the Osmocom proxy for the 3GPP Gb interface. The Gb</span><br><span> interface is defined by 3GPP as the protocol between the BSS and the</span><br><span> SGSN inside the 2G/2.5G/2.75G packet switched network domain.</span><br><span> </span><br><span> As Osmocom implements a BTS-colocated PCU, there are potentially many</span><br><span> Gb interface connections between all those many PCUs in the network</span><br><span> and the SGSN. This can be cumbersome to configure/maintain at the</span><br><span style="color: hsl(0, 100%, 40%);">-SGSN sine.</span><br><span style="color: hsl(120, 100%, 40%);">+SGSN side.</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">-OsmoGbPROXY aggregates many PCU-facing Gb connections into one Gb</span><br><span style="color: hsl(120, 100%, 40%);">+OsmoGbProxy aggregates many PCU-facing Gb connections into one Gb</span><br><span> connection to the SGSN. This is achieved by</span><br><span> </span><br><span> * maintaining sepaate NS-VCs on the PCU side and on the SGSN side</span><br><span>@@ -21,11 +21,12 @@</span><br><span> * having some special handling for the signaling BVC (BVCI=0) which is</span><br><span> shared among all the PCUs connected to the proxy</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> === Data Model</span><br><span> </span><br><span> ==== gbproxy_config</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">-This contains the parsed configuration of the OsmoGbPROXY.</span><br><span style="color: hsl(120, 100%, 40%);">+This contains the parsed configuration of the OsmoGbProxy.</span><br><span> </span><br><span> ==== gproxy_peer</span><br><span> </span><br><span>diff --git a/doc/manuals/osmogbproxy-usermanual.adoc b/doc/manuals/osmogbproxy-usermanual.adoc</span><br><span>index c4e0b9d..c93ebec 100644</span><br><span>--- a/doc/manuals/osmogbproxy-usermanual.adoc</span><br><span>+++ b/doc/manuals/osmogbproxy-usermanual.adoc</span><br><span>@@ -9,6 +9,8 @@</span><br><span> </span><br><span> include::{srcdir}/chapters/gbproxy-overview.adoc[]</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+include::{srcdir}/chapters/gbproxy-details.adoc[]</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> include::{srcdir}/chapters/gbproxy-running.adoc[]</span><br><span> </span><br><span> include::{srcdir}/chapters/gbproxy-control.adoc[]</span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/c/osmo-sgsn/+/20281">change 20281</a>. 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<div style="display:none"> Gerrit-Project: osmo-sgsn </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-Change-Id: I383fcd3864a94177f13909c6b8c15648900d3201 </div>
<div style="display:none"> Gerrit-Change-Number: 20281 </div>
<div style="display:none"> Gerrit-PatchSet: 1 </div>
<div style="display:none"> Gerrit-Owner: daniel <dwillmann@sysmocom.de> </div>
<div style="display:none"> Gerrit-MessageType: newchange </div>