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<p>Hello,</p>
<p>the keepalive is done via sort of a trick which needs to detect:</p>
<p> - if one side is no longer connected to the network --
keepalive results in retransmission timeout</p>
<p> - if one side is no longer knowing the dialog - so call-id,
to-tag and from-tag values do not match -- keepalive results in
481 Call Leg/Transaction Does Not Exist<br>
</p>
Any other case is not relevant for the keepalive purpose of
detecting if a side is still in the call.<br>
<br>
Therefore, CSeq is intentionally set to an lower value than expected
by each side, in order not to impact what is sent by each side.<br>
<br>
If you want to do nat keepalive for the duration of the dialog, that
can be achieved by using nat_traversal. Or if you use a location
service, usrloc+nathelper does it for the registration session.<br>
<br>
Cheers,<br>
Daniel<br>
<br>
<div class="moz-cite-prefix">On 17.04.18 08:25, Oded Arbel wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAFBa_-ortQ+VzODM6_LGopg5SyQ=NOutzYb1tOqv9OqjkBs8Ag@mail.gmail.com"><br>
<br>
<div class="gmail_quote">
<div dir="ltr">On Mon, Apr 16, 2018, 16:24 Dmitri Savolainen
<<a href="mailto:savolainen@erinaco.ru"
moz-do-not-send="true">savolainen@erinaco.ru</a>> wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex"><span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">Ideally
I think Kamailio should send correct (i.e increasing)
CSeq numbers.</span><br>
</blockquote>
</div>
<div dir="ltr">
<div>in my mind it can't be increased by kamailio because
of:</div>
<div>1. kamailio send OPTIONS with cseq+1</div>
<div>2. media server may send some indialog reinvite with
cseq+1 and then kamailio have to remember that OPTIONS
and translate reinvite to cseq+2.</div>
</div>
</blockquote>
</div>
<div><br>
</div>
<div>Fair point, statelessness is important.</div>
<div><br>
</div>
<div><br>
</div>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div>I don't know why for "<span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px;background-color:rgb(255,255,255)">ka-src"
CSeq is 0 and for "ka-dst" the one is equal: so may be
it is possible to be fixed </span></div>
</div>
</blockquote>
</div>
<div><br>
</div>
<div>I'll investigate, under the assumption everyone agrees it's a
bug.</div>
<div><br>
</div>
<div><br>
</div>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div><span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br>
</span></span></span></div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex"><span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><span> </span>(for
example BYE) to be dropped by the firewall.</span></blockquote>
</div>
<div dir="ltr">
<div>this may be achieved by</div>
<div>1. usrloc pinging</div>
</div>
</blockquote>
</div>
<div><br>
</div>
<div>I'm not sure that is usrloc pinging, but if you mean
nathelper's nat_ping, then that wouldn't work for me because
it's only for MUAs that use REGISTER, which on my system does
not always happen.</div>
<div><br>
</div>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div>2. short re-registration period for endpoint (60 sec
for ex)</div>
</div>
</blockquote>
</div>
<div><br>
</div>
<div>Aside from the fact that REGISTER is not guaranteed to ever
happen, this is also a UA setting that can't be enforced by the
server and has serious implications on battery life outside of a
call.</div>
<div><br>
</div>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div>3. let's media server send options by itself via
kamailio</div>
</div>
</blockquote>
</div>
<div><br>
</div>
<div>This may or may not be possible on my setup, I'll have to
investigate - thanks for the suggestion!</div>
<div><br>
</div>
-- <br>
<div dir="ltr" class="gmail_signature"
data-smartmail="gmail_signature">
<div dir="ltr">
<p dir="ltr"><span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px">Oded
Arbel</span></p>
<div
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px"><a
href="mailto:oded.arbel@greenfieldtech.net"
target="_blank" style="font-size:12.8px"
moz-do-not-send="true">oded.arbel@greenfieldtech.net</a><br>
</div>
<div
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px"><a
href="http://greenfieldtech.net/" target="_blank"
moz-do-not-send="true"><img alt="Greenfield Tech"
src="https://docs.google.com/uc?export=download&id=0B7YBJmVm7aC4QzZkNE1INkRUV1k&revid=0B7YBJmVm7aC4cjVKbHk4Qld3akpOWFJFd0dDQnRVVnROaEg0PQ"
moz-do-not-send="true"></a></div>
</div>
</div>
<br>
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<pre wrap="">_______________________________________________
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</pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Daniel-Constantin Mierla
<a class="moz-txt-link-abbreviated" href="http://www.twitter.com/miconda">www.twitter.com/miconda</a> -- <a class="moz-txt-link-abbreviated" href="http://www.linkedin.com/in/miconda">www.linkedin.com/in/miconda</a>
Kamailio Advanced Training - April 16-18, 2018, Berlin - <a class="moz-txt-link-abbreviated" href="http://www.asipto.com">www.asipto.com</a>
Kamailio World Conference - May 14-16, 2018 - <a class="moz-txt-link-abbreviated" href="http://www.kamailioworld.com">www.kamailioworld.com</a></pre>
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