Re: [SR-Users] ACK to 486 is not being proxied - sr-users

20 May 2011


      Please do not write private emails, keep the mailing list cc-ed.
Can you get the output of:
ngrep -d any -qt -W byline port 5040
on kamailio server for such a call? Include all messages, since you may 
miss something in your filtering (like you did below), of course you can 
mask the ip addresses.
Also, be sure you do t_relay() to forward the invite from kamailio on.
Cheers,
Daniel
On 5/20/11 3:47 PM, Carl Wagner wrote:
...
Daniel,
With a non-2xx reply being hop-by-hop, shouldn't Kamailio receive the 
486, send the ACK to the sender, and then proxy the 486?
I am not seeing the 486 message in the Kamailio log so I assume that 
it automatically handles it without hitting the kamailio.cfg script?  
Or do I need to set up a failure_route to catch the 486 and send the 
ACK there?
Please see the log below.
Thanks,
Carl
# Asterisk to Kamailio
U 2011/05/19 14:13:01.467157 3.4.5.167:5060 -> 3.4.5.164:5060
INVITE sip:+13031112222@3.4.5.164 SIP/2.0.
Via: SIP/2.0/UDP 3.4.5.167:5060;branch=z9hG4bK3183c9de;rport.
From: "+13032223333" sip:+13032223333@3.4.5.167;tag=as1f559f5a.
To: sip:+13031112222@3.4.5.164.
Contact: sip:+13032223333@3.4.5.167.
Call-ID: 37ef92a26c31a7f85958ae996d49a872@3.4.5.167.
CSeq: 102 INVITE.
User-Agent: Asterisk.
Max-Forwards: 70.
Date: Thu, 19 May 2011 20:13:01 GMT.
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.
Supported: replaces.
Content-Type: application/sdp.
Content-Length: 238.
.
v=0.
o=root 27806 27806 IN IP4 3.4.5.167.
s=session.
c=IN IP4 3.4.5.167.
t=0 0.
m=audio 13424 RTP/AVP 0 101.
a=rtpmap:0 PCMU/8000.
a=rtpmap:101 telephone-event/8000.
a=fmtp:101 0-16.
a=silenceSupp:off - - - -.
a=ptime:20.
a=sendrecv.
# Kamailio to provider
U 2011/05/19 14:13:01.468627 3.4.5.164:5060 -> 2.3.4.40:5060
INVITE sip:+13031112222@2.3.4.40:5060 SIP/2.0.
Record-Route: sip:3.4.5.164;lr=on.
Via: SIP/2.0/UDP 3.4.5.164;branch=0.
Via: SIP/2.0/UDP 3.4.5.167:5060;branch=z9hG4bK3183c9de;rport=5060.
From: "+13032223333" sip:+13032223333@3.4.5.167;tag=as1f559f5a.
To: sip:+13031112222@2.3.4.40:5060.
Contact: sip:+13032223333@3.4.5.167.
Call-ID: 37ef92a26c31a7f85958ae996d49a872@3.4.5.167.
CSeq: 102 INVITE.
User-Agent: Asterisk.
Max-Forwards: 69.
Date: Thu, 19 May 2011 20:13:01 GMT.
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.
Supported: replaces.
Content-Type: application/sdp.
Content-Length: 238.
.
v=0.
o=root 27806 27806 IN IP4 3.4.5.167.
s=session.
c=IN IP4 3.4.5.167.
t=0 0.
m=audio 13424 RTP/AVP 0 101.
a=rtpmap:0 PCMU/8000.
a=rtpmap:101 telephone-event/8000.
a=fmtp:101 0-16.
a=silenceSupp:off - - - -.
a=ptime:20.
a=sendrecv.
U 2011/05/19 14:13:01.511775 2.3.4.40:37897 -> 3.4.5.164:5060
SIP/2.0 100 Trying.
Via: SIP/2.0/UDP 3.4.5.164;branch=0,SIP/2.0/UDP 
3.4.5.167:5060;branch=z9hG4bK3183c9de;rport=5060.
From: "+13032223333" sip:+13032223333@3.4.5.167;tag=as1f559f5a.
To: sip:+13031112222@2.3.4.40:5060.
Call-ID: 37ef92a26c31a7f85958ae996d49a872@3.4.5.167.
CSeq: 102 INVITE.
Content-Length: 0.
.
U 2011/05/19 14:13:01.513162 3.4.5.164:5060 -> 3.4.5.167:5060
SIP/2.0 100 Trying.
Via: SIP/2.0/UDP 3.4.5.167:5060;branch=z9hG4bK3183c9de;rport=5060.
From: "+13032223333" sip:+13032223333@3.4.5.167;tag=as1f559f5a.
To: sip:+13031112222@2.3.4.40:5060.
Call-ID: 37ef92a26c31a7f85958ae996d49a872@3.4.5.167.
CSeq: 102 INVITE.
Content-Length: 0.
.
# provider says they are busy
U 2011/05/19 14:13:03.239462 2.3.4.40:37897 -> 3.4.5.164:5060
SIP/2.0 486 Busy Here.
Via: SIP/2.0/UDP 3.4.5.164;branch=0,SIP/2.0/UDP 
3.4.5.167:5060;branch=z9hG4bK3183c9de;rport=5060.
Record-Route: sip:3.4.5.164;lr=on.
From: "+13032223333" sip:+13032223333@3.4.5.167;tag=as1f559f5a.
To: sip:+13031112222@2.3.4.40:5060;tag=VPST506071629352.
Call-ID: 37ef92a26c31a7f85958ae996d49a872@3.4.5.167.
CSeq: 102 INVITE.
Contact: sip:+13031112222@2.3.4.40:5060;transport=udp.
Content-Length: 0.
.
#
# should Kamailio send the ACK here?
#
# Kamailio proxies the 486 to Asterisk
U 2011/05/19 14:13:03.240820 3.4.5.164:5060 -> 3.4.5.167:5060
SIP/2.0 486 Busy Here.
Via: SIP/2.0/UDP 3.4.5.167:5060;branch=z9hG4bK3183c9de;rport=5060.
Record-Route: sip:3.4.5.164;lr=on.
From: "+13032223333" sip:+13032223333@3.4.5.167;tag=as1f559f5a.
To: sip:+13031112222@2.3.4.40:5060;tag=VPST506071629352.
Call-ID: 37ef92a26c31a7f85958ae996d49a872@3.4.5.167.
CSeq: 102 INVITE.
Contact: sip:+13031112222@2.3.4.40:5060;transport=udp.
Content-Length: 0.
.
# ACK from Asterisk - should be swallowed by Kamailio
U 2011/05/19 14:13:03.243870 3.4.5.167:5060 -> 3.4.5.164:5060
ACK sip:+13031112222@3.4.5.164 SIP/2.0.
Via: SIP/2.0/UDP 3.4.5.167:5060;branch=z9hG4bK3183c9de;rport.
From: "+13032223333" sip:+13032223333@3.4.5.167;tag=as1f559f5a.
To: sip:+13031112222@3.4.5.164;tag=VPST506071629352.
Contact: sip:+13032223333@3.4.5.167.
Call-ID: 37ef92a26c31a7f85958ae996d49a872@3.4.5.167.
CSeq: 102 ACK.
User-Agent: Asterisk.
Max-Forwards: 70.
Content-Length: 0.
.
==== a bunch of retransmitted 486's chopped =============
On 05/19/2011 02:30 AM, Daniel-Constantin Mierla wrote:
...
Hello,
the ACK for non-2xx replies is hop-by-hop, meaning that kamailio will 
generate one when the reply is received, will send back the reply and 
when the ack comes from upstream, it will absorb it.
In this case it seems that ack is not matching any invite transaction 
and thus is not known where to send it.
Can you send the invite, reply and the ack requests taken with ngrep 
for such case? Maybe is something broken in the content of the message.
Cheers,
Daniel
On 5/18/11 11:23 PM, Carl Wagner wrote:
...
Hi,
I have Kamailio set up to act as a proxy and load balancer.  Most 
things are working correctly but for some reason I can't get 
Kamailio to proxy an ACK to a 486 Busy.
I assume that it is something wrong that I have done in the 
kamailio.cfg file but I am not seeing it.
Does the t_check_trans() return false because the call state is Busy?
Please let me know if you need other logs or information.
Thanks in advance,
Carl
================== Call flow:  (from ngrep)  ======================
Asterisk     Kamailio     Provider
 INVITE--------->
                   INVITE--------->
<----------100 Trying
<---------100 Trying
<----------486 Busy
<---------486 Busy
ACK------------->
====== Kamailio does not proxy the ACK here =======
<----------486 Busy
<---------486 Busy
ACK------------->
<----------486 Busy
<---------486 Busy
=== kamailio.cfg snippet
...
route
{
   route(REQINIT);  # remove malformed messages
# handle requests within SIP dialogs
   route(WITHINDLG);
  ...
}
###################################################################
# Handle requests within SIP dialogs (request has a TO: Tag)
route[WITHINDLG]
{
   if (has_totag())
   {
xlog("L_INFO", "  WITHINDLG: SIP Request: [$rm] ruri=[$ru]  (from 
[$fu] to [$tu], Call-ID=[$ci], CSeq=[$cs])\n");
      if (loose_route())
      {
         ...
      }
      else  # not loose_route
      {
         if ( is_method("ACK") )
         {
            if ( t_check_trans() )  # see if a message is related to 
a transaction
            {
               ...
            }
            else
            {
               # ACK without matching transaction ... ignore and 
discard
xlog("L_INFO", "  WITHINDLG: has TO: tag AND loose_route is NOT true 
and is_method = ACK and t_check_trans=FALSE\n");
# not forwarded here!!!   Tried both t_relay and forward.
               # $var(a) = t_relay();
               $var(a) = forward();
               xlog ("L_INFO", "  WITHINDLG: (ReturnCode = [$var(a)] 
exiting)\n");
           exit;
        }
     }
     sl_send_reply("404","Not here");
  }
  exit;

}
}
============= End of kamailio.cfg ================
============= /var/log/messages - snippit of the message ==========
May 18 11:21:05 kam0 /usr/sbin/kamailio[21282]: INFO: <script>: 
======== processing new message
May 18 11:21:05 kam0 /usr/sbin/kamailio[21282]: INFO: <script>: 
MAIN: SIP Request: [ACK] ruri=[sip:+13031112222@2.3.4.5]  (from 
[sip:+13031112222@3.4.5.6] to [sip:+13031112222@2.3.4.5], 
Call-ID=[21a30b9168e0a8c963d47ca1361cef77@3.4.5.6]) CSeq=[102]
May 18 11:21:05 kam0 /usr/sbin/kamailio[21282]: INFO: <script>:   
WITHINDLG: SIP Request: [ACK] ruri=[sip:+13031112222@2.3.4.5]  (from 
[sip:+13031112222@3.4.5.6] to [sip:+13031112222@2.3.4.5], 
Call-ID=[21a30b9168e0a8c963d47ca1361cef77@3.4.5.6], CSeq=[102])
May 18 11:21:05 kam0 /usr/sbin/kamailio[21282]: INFO: <script>:   
WITHINDLG: has TO: tag
May 18 11:21:05 kam0 /usr/sbin/kamailio[21282]: INFO: <script>:   
WITHINDLG: has TO: tag AND loose_route is NOT true and is_method = 
ACK and t_check_trans=FALSE
May 18 11:21:05 kam0 /usr/sbin/kamailio[21282]: INFO: <script>:   
WITHINDLG:    the ACK to a 486 was not being processed so I am 
adding t_relay here
May 18 11:21:05 kam0 /usr/sbin/kamailio[21282]: INFO: <script>:   
WITHINDLG: (ReturnCode = [1] exiting)

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-- 
Daniel-Constantin Mierla
http://www.asipto.com
-- 
Daniel-Constantin Mierla -- http://www.asipto.com
http://linkedin.com/in/miconda -- http://twitter.com/miconda