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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Hello Max,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Please find below chart that indicate time skew is happening in the setup.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">I have also attached the excel sheet used for this analysis here for reference.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">TS4 in downlink is considered for drawing the plot. Please note that block duration value of 18 and 23 milliseconds are acceptable as transmission FNs increment
by pattern of 4,4,5,4,4,5,..and so on.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">4FN duration is 18.4ms and 5 FN is 23 ms approx.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">But the spikes in the system as high as 26.8ms may result in incorrect air interface behavior from L1.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><img width="975" height="274" id="Chart_x0020_1" src="cid:image002.png@01D17101.8DA5BBD0"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Regards<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Saurabh<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"> Max [mailto:msuraev@sysmocom.de]
<br>
<b>Sent:</b> Friday, February 26, 2016 10:37 PM<br>
<b>To:</b> Saurabh Sharan <Saurabh.Sharan@radisys.com>; osmocom-net-gprs@lists.osmocom.org<br>
<b>Subject:</b> Re: PCU scheduling and PACCH timeout question<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">I'm not sure what to make of this timing difference. I'm using sysmoBTS hw to test different osmoPCU versions (including ssharan/egprs) and I can see pacch timeouts on all of those I've tried. For some phones
it really breaks connectivity, others seems to be able to ignore it somehow. I do not see a pattern yet.<br>
<br>
Do you have some test setup where you try it and see if it's the same for you?<o:p></o:p></p>
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<p class="MsoNormal">On 02/26/2016 04:13 PM, Saurabh Sharan wrote:<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Hello Max,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Though I have not analyzed the missing UL poll response, few of my observations from the pcap file attached is mentioned below<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:0in;text-indent:-.25in;mso-list:l0 level1 lfo1">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">There seems to be difference in FN UL versus DL being processed at any given time by the order of approx. 10 FNs, example given below<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:0in;text-indent:-.25in;mso-list:l3 level1 lfo2">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><span style="mso-list:Ignore">a.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Packet 7174 , FN 1137361 in DL @ 15:33:22.511809393<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:0in;text-indent:-.25in;mso-list:l3 level1 lfo2">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><span style="mso-list:Ignore">b.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Packet 7190, FN 1137361 in UL @ 15:33:22.559427972<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:0in;text-indent:-.25in;mso-list:l3 level1 lfo2">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><span style="mso-list:Ignore">c.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From above example difference in time is 48milliseconds or approx.. 10FN duration<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:0in;text-indent:-.25in;mso-list:l2 level1 lfo3">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">For processing DL timeslots 2 to 6 at any given DL FN time taken seems to be approx. 3milliseconds, example given below<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:0in;text-indent:-.25in;mso-list:l1 level1 lfo4">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><span style="mso-list:Ignore">d.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Packet 7174 , FN 1137361 in DL @ 15:33:22.511809393 for TS 2<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:0in;text-indent:-.25in;mso-list:l1 level1 lfo4">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><span style="mso-list:Ignore">e.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Packet 7178, FN 1137361 in DL @ 15:33:22.514310379 for TS 6<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Please let me know if these are known behavior in your integration environment ?
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">These time variations may have an impact on the poll response behavior from MS as well.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Regards<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Saurabh<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">-----Original Message-----<br>
From: Max [<a href="mailto:msuraev@sysmocom.de">mailto:msuraev@sysmocom.de</a>] <br>
Sent: Thursday, February 25, 2016 3:58 PM<br>
To: <a href="mailto:osmocom-net-gprs@lists.osmocom.org">osmocom-net-gprs@lists.osmocom.org</a>; Saurabh Sharan
<a href="mailto:Saurabh.Sharan@radisys.com"><Saurabh.Sharan@radisys.com></a><br>
Subject: PCU scheduling and PACCH timeout question<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Hello.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">I'm trying to debug issue with current OsmoPCU master when some basebands ignore polling requests.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">The debug output from RLCMAC layer and corresponding .pcap files are attached.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">The issue appears somewhere after line 112 in debug.log The corresponding packet in pcu.pcapng is 6866<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">After receiving PACKET_CONTROL_ACK from phone we're trying to schedule polling at FN 1137123 (see packet 6869 in pcap) and than at FN 1137127 (packet 6874) which subsequently
fails.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">This seems suspiciously close but I have not found in the spec yet if this is legitimate thing to do.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">There are several other occurrences like that in both log and pcap.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Have you experienced something like this? Do you have an idea why only some basebands are affected while others work fine?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">--<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Max Suraev <<a href="mailto:msuraev@sysmocom.de">msuraev@sysmocom.de</a>>
<a href="http://www.sysmocom.de/">http://www.sysmocom.de/</a> =======================================================================<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">* sysmocom - systems for mobile communications GmbH<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">* Alt-Moabit 93<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">* 10559 Berlin, Germany<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">* Sitz / Registered office: Berlin, HRB 134158 B<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">* Geschaeftsfuehrer / Managing Directors: Holger Freyther, Harald Welte<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><br>
<br>
<o:p></o:p></p>
<pre>-- <o:p></o:p></pre>
<pre>Max Suraev <a href="mailto:msuraev@sysmocom.de"><msuraev@sysmocom.de></a> <a href="http://www.sysmocom.de/">http://www.sysmocom.de/</a><o:p></o:p></pre>
<pre>======================================================================= <o:p></o:p></pre>
<pre>* sysmocom - systems for mobile communications GmbH<o:p></o:p></pre>
<pre>* Alt-Moabit 93 <o:p></o:p></pre>
<pre>* 10559 Berlin, Germany<o:p></o:p></pre>
<pre>* Sitz / Registered office: Berlin, HRB 134158 B <o:p></o:p></pre>
<pre>* Geschaeftsfuehrer / Managing Directors: Holger Freyther, Harald Welte <o:p></o:p></pre>
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