https://osmocom.org/https://osmocom.org/favicon.ico?16647414092018-06-18T17:50:27ZOpen Source Mobile CommunicationsOsmoBTS - Bug #3353: osmo-bts: TTCN3 BTS_Tests.TC_rll_est_ind fail behavior not clearhttps://osmocom.org/issues/3353?journal_id=99542018-06-18T17:50:27Zpespin
<ul><li><strong>Related to</strong> <i><a class="issue tracker-2 status-7 priority-3 priority-high3" href="/issues/3155">Feature #3155</a>: execute BTS_Tests.ttcn with real (C123) phone hardware in LTHW setup</i> added</li></ul> OsmoBTS - Bug #3353: osmo-bts: TTCN3 BTS_Tests.TC_rll_est_ind fail behavior not clearhttps://osmocom.org/issues/3353?journal_id=100102018-06-23T18:37:14Zlaforge
<ul><li><strong>Assignee</strong> set to <i>pespin</i></li></ul> OsmoBTS - Bug #3353: osmo-bts: TTCN3 BTS_Tests.TC_rll_est_ind fail behavior not clearhttps://osmocom.org/issues/3353?journal_id=100112018-06-23T18:41:07Zlaforge
<ul></ul><p>pespin wrote:</p>
<blockquote>
<p>When running the test with osmo-bts-trx (same when checking the pcap file from the virtphy one), I saw that the BTS is sending ERROR INDICATION to the BSC, but those messages don't seem to be expected at all by reading the test code. The test only expected either a normal Establish Indiciation (with or without L3 payload) to be received, or otherwise doesn't care what's received.</p>
</blockquote>
<blockquote>
<p>It should be clarified whether it is a good behavior to receive an Error indication or not. In case it's not expected, I added this code in TTCN3 but I don't know why, it never triggers (despite seeing Error Indications in pcap file):</p>
</blockquote>
<p>I think the test is correct. We expect a RLL EST IND, and no RLL ERR IND.</p>
<blockquote>
<p>After looking around for a while, though, I think the Error indication messages are expected and they should be checked in the test code.</p>
</blockquote>
<p>The important question is <em>why</em> you come to that conclusion. Without any argument, I beg to differ :)</p>
<blockquote>
Error 14 is "RLL_CAUSE_SABM_INFO_NOTALL", and it's triggered in lapdm_rx_not_permitted() on code paths with following comments:
<ul>
<li>/* no contention resolution on SACCH */</li>
<li>/* SAPI3 doesn't support contention resolution */</li>
</ul>
<p>So, according to those comments or code paths, the ttcn3 test expectations are afaiu, because these two lines expect an Establish indication for SAPI3 (and SACCH on one of them):</p>
</blockquote>
<p>So what Error 14 seems to be about is that the L3 INFO payload immediately inside the SABM message is not allowed in some cases. This is correct. L3 payload in the SABM is only allowed for contention resolution, and that in turn is only used on SAPI0 of the main DCCH.</p>
<p>The following two lines you quoted from the test are doing a <strong>normal</strong> establishment, and not a <strong>contention resolution</strong> establishment.<br /><pre>
/* normal SAPI3 establishment on main DCCH */
valueof(t_EITC(3, valueof(ts_RslLinkID_DCCH(3)), ''O, true)),
/* normal SAPI3 establishment on SACCH */
valueof(t_EITC(3, valueof(ts_RslLinkID_SACCH(3)), ''O, true))
</pre></p>
<p>The <code>''O</code> part is passing a zero-length L3 PDU, and hence no L3 INFO is expected.</p> OsmoBTS - Bug #3353: osmo-bts: TTCN3 BTS_Tests.TC_rll_est_ind fail behavior not clearhttps://osmocom.org/issues/3353?journal_id=139922019-04-15T13:55:05Zpespin
<ul><li><strong>Status</strong> changed from <i>New</i> to <i>Closed</i></li></ul><p>Clarified quite long time ago.</p>